# LinearLayoutManager
Artifact: [androidx.recyclerview:recyclerview](https://developer.android.com/jetpack/androidx/releases/recyclerview) [View Source](https://cs.android.com/search?q=file:androidx/recyclerview/widget/LinearLayoutManager.java+class:androidx.recyclerview.widget.LinearLayoutManager) Added in [1.0.0](https://developer.android.com/jetpack/androidx/releases/recyclerview#1.0.0)
*** ** * ** ***
```
public class LinearLayoutManager extends RecyclerView.LayoutManager implements ItemTouchHelper.ViewDropHandler, RecyclerView.SmoothScroller.ScrollVectorProvider
```
|---|---|---|
| [java.lang.Object](https://developer.android.com/reference/java/lang/Object.html) |||
| ↳ | [androidx.recyclerview.widget.RecyclerView.LayoutManager](https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager) ||
| | ↳ | [androidx.recyclerview.widget.LinearLayoutManager](https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager) |
Known direct subclasses [GridLayoutManager](https://developer.android.com/reference/androidx/recyclerview/widget/GridLayoutManager), [WearableLinearLayoutManager](https://developer.android.com/reference/androidx/wear/widget/WearableLinearLayoutManager)
|---|---|
| `https://developer.android.com/reference/androidx/recyclerview/widget/GridLayoutManager` | A `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager` implementations that lays out items in a grid. |
| `https://developer.android.com/reference/androidx/wear/widget/WearableLinearLayoutManager` | This wear-specific implementation of `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager` provides basic offsetting logic for updating child layout. |
*** ** * ** ***
A `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager` implementation which provides similar functionality to `https://developer.android.com/reference/android/widget/ListView.html`.
## Summary
| ### Nested types |
|---|
| `protected class https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager.LayoutChunkResult` |
| ### Constants |
|---|---|
| `static final int` | `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#HORIZONTAL() = 0` |
| `static final int` | `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#INVALID_OFFSET() = -2147483648` |
| `static final int` | `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#VERTICAL() = 1` |
| ### Public constructors |
|---|
| `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#LinearLayoutManager(android.content.Context)(https://developer.android.com/reference/android/content/Context.html context)` Creates a vertical LinearLayoutManager |
| `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#LinearLayoutManager(android.content.Context,int,boolean)( https://developer.android.com/reference/android/content/Context.html context, int orientation, boolean reverseLayout )` |
| `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#LinearLayoutManager(android.content.Context,android.util.AttributeSet,int,int)( https://developer.android.com/reference/android/content/Context.html context, https://developer.android.com/reference/android/util/AttributeSet.html attrs, int defStyleAttr, int defStyleRes )` Constructor used when layout manager is set in XML by RecyclerView attribute "layoutManager". |
| ### Public methods |
|---|---|
| `void` | `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#assertNotInLayoutOrScroll(java.lang.String)(https://developer.android.com/reference/java/lang/String.html message)` Checks if RecyclerView is in the middle of a layout or scroll and throws an `https://developer.android.com/reference/java/lang/IllegalStateException.html` if it **is**. |
| `boolean` | `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#canScrollHorizontally()()` |
| `boolean` | `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#canScrollVertically()()` |
| `void` | `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#collectAdjacentPrefetchPositions(int,int,androidx.recyclerview.widget.RecyclerView.State,androidx.recyclerview.widget.RecyclerView.LayoutManager.LayoutPrefetchRegistry)( int dx, int dy, https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.State state, https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager.LayoutPrefetchRegistry layoutPrefetchRegistry )` Gather all positions from the LayoutManager to be prefetched, given specified momentum. |
| `void` | `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#collectInitialPrefetchPositions(int,androidx.recyclerview.widget.RecyclerView.LayoutManager.LayoutPrefetchRegistry)( int adapterItemCount, https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager.LayoutPrefetchRegistry layoutPrefetchRegistry )` Gather all positions from the LayoutManager to be prefetched in preperation for its RecyclerView to come on screen, due to the movement of another, containing RecyclerView. |
| `int` | `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#computeHorizontalScrollExtent(androidx.recyclerview.widget.RecyclerView.State)(https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.State state)` Override this method if you want to support scroll bars. |
| `int` | `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#computeHorizontalScrollOffset(androidx.recyclerview.widget.RecyclerView.State)(https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.State state)` Override this method if you want to support scroll bars. |
| `int` | `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#computeHorizontalScrollRange(androidx.recyclerview.widget.RecyclerView.State)(https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.State state)` Override this method if you want to support scroll bars. |
| `https://developer.android.com/reference/android/graphics/PointF.html` | `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#computeScrollVectorForPosition(int)(int targetPosition)` Should calculate the vector that points to the direction where the target position can be found. |
| `int` | `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#computeVerticalScrollExtent(androidx.recyclerview.widget.RecyclerView.State)(https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.State state)` Override this method if you want to support scroll bars. |
| `int` | `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#computeVerticalScrollOffset(androidx.recyclerview.widget.RecyclerView.State)(https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.State state)` Override this method if you want to support scroll bars. |
| `int` | `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#computeVerticalScrollRange(androidx.recyclerview.widget.RecyclerView.State)(https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.State state)` Override this method if you want to support scroll bars. |
| `int` | `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#findFirstCompletelyVisibleItemPosition()()` Returns the adapter position of the first fully visible view. |
| `int` | `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#findFirstVisibleItemPosition()()` Returns the adapter position of the first visible view. |
| `int` | `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#findLastCompletelyVisibleItemPosition()()` Returns the adapter position of the last fully visible view. |
| `int` | `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#findLastVisibleItemPosition()()` Returns the adapter position of the last visible view. |
| `https://developer.android.com/reference/android/view/View.html` | `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#findViewByPosition(int)(int position)` Finds the view which represents the given adapter position. |
| `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutParams` | `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#generateDefaultLayoutParams()()` Create a default `LayoutParams` object for a child of the RecyclerView. |
| `int` | `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#getInitialPrefetchItemCount()()` Gets the number of items to prefetch in `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#collectInitialPrefetchPositions(int,androidx.recyclerview.widget.RecyclerView.LayoutManager.LayoutPrefetchRegistry)`, which defines how many inner items should be prefetched when this LayoutManager's RecyclerView is nested inside another RecyclerView. |
| `int` | `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#getOrientation()()` Returns the current orientation of the layout. |
| `boolean` | `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#getRecycleChildrenOnDetach()()` Returns whether LayoutManager will recycle its children when it is detached from RecyclerView. |
| `boolean` | `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#getReverseLayout()()` Returns if views are laid out from the opposite direction of the layout. |
| `boolean` | `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#getStackFromEnd()()` |
| `boolean` | `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#isAutoMeasureEnabled()()` Returns whether the measuring pass of layout should use the AutoMeasure mechanism of `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView` or if it should be done by the LayoutManager's implementation of `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#onMeasure(androidx.recyclerview.widget.RecyclerView.Recycler,androidx.recyclerview.widget.RecyclerView.State,int,int)`. |
| `boolean` | `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#isLayoutReversed()()` Query if the layout is in reverse order. |
| `boolean` | `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#isSmoothScrollbarEnabled()()` Returns the current state of the smooth scrollbar feature. |
| `void` | `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#onDetachedFromWindow(androidx.recyclerview.widget.RecyclerView,androidx.recyclerview.widget.RecyclerView.Recycler)(https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView view, https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.Recycler recycler)` Called when this LayoutManager is detached from its parent RecyclerView or when its parent RecyclerView is detached from its window. |
| `https://developer.android.com/reference/android/view/View.html` | `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#onFocusSearchFailed(android.view.View,int,androidx.recyclerview.widget.RecyclerView.Recycler,androidx.recyclerview.widget.RecyclerView.State)( https://developer.android.com/reference/android/view/View.html focused, int direction, https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.Recycler recycler, https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.State state )` Called when searching for a focusable view in the given direction has failed for the current content of the RecyclerView. |
| `void` | `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#onInitializeAccessibilityEvent(android.view.accessibility.AccessibilityEvent)(https://developer.android.com/reference/android/view/accessibility/AccessibilityEvent.html event)` |
| `void` | `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#onInitializeAccessibilityNodeInfo(androidx.recyclerview.widget.RecyclerView.Recycler,androidx.recyclerview.widget.RecyclerView.State,androidx.core.view.accessibility.AccessibilityNodeInfoCompat)( @https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.Recycler recycler, @https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.State state, @https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/androidx/core/view/accessibility/AccessibilityNodeInfoCompat info )` Called by the AccessibilityDelegate when the information about the current layout should be populated. |
| `void` | `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#onLayoutChildren(androidx.recyclerview.widget.RecyclerView.Recycler,androidx.recyclerview.widget.RecyclerView.State)( https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.Recycler recycler, https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.State state )` Lay out all relevant child views from the given adapter. |
| `void` | `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#onLayoutCompleted(androidx.recyclerview.widget.RecyclerView.State)(https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.State state)` Called after a full layout calculation is finished. |
| `void` | `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#onRestoreInstanceState(android.os.Parcelable)(https://developer.android.com/reference/android/os/Parcelable.html state)` Called when the RecyclerView is ready to restore the state based on a previous RecyclerView. |
| `https://developer.android.com/reference/android/os/Parcelable.html` | `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#onSaveInstanceState()()` Called when the LayoutManager should save its state. |
| `void` | `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#prepareForDrop(android.view.View,android.view.View,int,int)(@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/android/view/View.html view, @https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/android/view/View.html target, int x, int y)` Called by the after a View is dropped over another View. |
| `int` | `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#scrollHorizontallyBy(int,androidx.recyclerview.widget.RecyclerView.Recycler,androidx.recyclerview.widget.RecyclerView.State)( int dx, https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.Recycler recycler, https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.State state )` Scroll horizontally by dx pixels in screen coordinates and return the distance traveled. |
| `void` | `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#scrollToPosition(int)(int position)` Scroll the RecyclerView to make the position visible. |
| `void` | `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#scrollToPositionWithOffset(int,int)(int position, int offset)` Scroll to the specified adapter position with the given offset from resolved layout start. |
| `int` | `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#scrollVerticallyBy(int,androidx.recyclerview.widget.RecyclerView.Recycler,androidx.recyclerview.widget.RecyclerView.State)( int dy, https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.Recycler recycler, https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.State state )` Scroll vertically by dy pixels in screen coordinates and return the distance traveled. |
| `void` | `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#setInitialPrefetchItemCount(int)(int itemCount)` Sets the number of items to prefetch in `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#collectInitialPrefetchPositions(int,androidx.recyclerview.widget.RecyclerView.LayoutManager.LayoutPrefetchRegistry)`, which defines how many inner items should be prefetched when this LayoutManager's RecyclerView is nested inside another RecyclerView. |
| `void` | `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#setOrientation(int)(int orientation)` Sets the orientation of the layout. |
| `void` | `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#setRecycleChildrenOnDetach(boolean)(boolean recycleChildrenOnDetach)` Set whether LayoutManager will recycle its children when it is detached from RecyclerView. |
| `void` | `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#setReverseLayout(boolean)(boolean reverseLayout)` Used to reverse item traversal and layout order. |
| `void` | `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#setSmoothScrollbarEnabled(boolean)(boolean enabled)` When smooth scrollbar is enabled, the position and size of the scrollbar thumb is computed based on the number of visible pixels in the visible items. |
| `void` | `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#setStackFromEnd(boolean)(boolean stackFromEnd)` Compatibility support for `https://developer.android.com/reference/android/widget/AbsListView.html#setStackFromBottom(boolean)` |
| `void` | `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#smoothScrollToPosition(androidx.recyclerview.widget.RecyclerView,androidx.recyclerview.widget.RecyclerView.State,int)( https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView recyclerView, https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.State state, int position )` Smooth scroll to the specified adapter position. |
| `boolean` | `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#supportsPredictiveItemAnimations()()` Returns whether this LayoutManager supports "predictive item animations". |
| ### Protected methods |
|---|---|
| `void` | `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#calculateExtraLayoutSpace(androidx.recyclerview.widget.RecyclerView.State,int[])( @https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.State state, @https://developer.android.com/reference/androidx/annotation/NonNull int[] extraLayoutSpace )` Calculates the amount of extra space (in pixels) that should be laid out by `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager` and stores the result in `extraLayoutSpace`. |
| `int` | `[getExtraLayoutSpace](https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#getExtraLayoutSpace(androidx.recyclerview.widget.RecyclerView.State))(https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.State state)` **This method is deprecated.** Use `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#calculateExtraLayoutSpace(androidx.recyclerview.widget.RecyclerView.State,int[])` instead.
|
| `boolean` | `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#isLayoutRTL()()` |
### Inherited methods
From [androidx.recyclerview.widget.RecyclerView.LayoutManager](https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager) `void` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#addDisappearingView(android.view.View)(https://developer.android.com/reference/android/view/View.html child)`
To be called only during `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#onLayoutChildren(androidx.recyclerview.widget.RecyclerView.Recycler,androidx.recyclerview.widget.RecyclerView.State)` to add a view to the layout that is known to be going away, either because it has been `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.Adapter#notifyItemRemoved(int)` or because it is actually not in the visible portion of the container but is being laid out in order to inform RecyclerView in how to animate the item out of view.
`void` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#addDisappearingView(android.view.View,int)(https://developer.android.com/reference/android/view/View.html child, int index)`
To be called only during `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#onLayoutChildren(androidx.recyclerview.widget.RecyclerView.Recycler,androidx.recyclerview.widget.RecyclerView.State)` to add a view to the layout that is known to be going away, either because it has been `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.Adapter#notifyItemRemoved(int)` or because it is actually not in the visible portion of the container but is being laid out in order to inform RecyclerView in how to animate the item out of view.
`void` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#addView(android.view.View)(https://developer.android.com/reference/android/view/View.html child)`
Add a view to the currently attached RecyclerView if needed.
`void` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#addView(android.view.View,int)(https://developer.android.com/reference/android/view/View.html child, int index)`
Add a view to the currently attached RecyclerView if needed.
`void` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#assertInLayoutOrScroll(java.lang.String)(https://developer.android.com/reference/java/lang/String.html message)`
Checks if RecyclerView is in the middle of a layout or scroll and throws an `https://developer.android.com/reference/java/lang/IllegalStateException.html` if it **is not**.
`void` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#attachView(android.view.View)(@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/android/view/View.html child)`
Reattach a previously `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#detachView(android.view.View)` view.
`void` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#attachView(android.view.View,int)(@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/android/view/View.html child, int index)`
Reattach a previously `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#detachView(android.view.View)` view.
`void` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#attachView(android.view.View,int,androidx.recyclerview.widget.RecyclerView.LayoutParams)(@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/android/view/View.html child, int index, https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutParams lp)`
Reattach a previously `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#detachView(android.view.View)` view.
`void` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#calculateItemDecorationsForChild(android.view.View,android.graphics.Rect)(
@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/android/view/View.html child,
@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/android/graphics/Rect.html outRect
)`
Calculates the item decor insets applied to the given child and updates the provided Rect instance with the inset values.
`boolean` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#checkLayoutParams(androidx.recyclerview.widget.RecyclerView.LayoutParams)(https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutParams lp)`
Determines the validity of the supplied LayoutParams object.
`static int` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#chooseSize(int,int,int)(int spec, int desired, int min)`
Chooses a size from the given specs and parameters that is closest to the desired size and also complies with the spec.
`void` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#detachAndScrapAttachedViews(androidx.recyclerview.widget.RecyclerView.Recycler)(@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.Recycler recycler)`
Temporarily detach and scrap all currently attached child views.
`void` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#detachAndScrapView(android.view.View,androidx.recyclerview.widget.RecyclerView.Recycler)(
@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/android/view/View.html child,
@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.Recycler recycler
)`
Detach a child view and add it to a `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.Recycler` scrap heap.
`void` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#detachAndScrapViewAt(int,androidx.recyclerview.widget.RecyclerView.Recycler)(int index, @https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.Recycler recycler)`
Detach a child view and add it to a `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.Recycler` scrap heap.
`void` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#detachView(android.view.View)(@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/android/view/View.html child)`
Temporarily detach a child view.
`void` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#detachViewAt(int)(int index)`
Temporarily detach a child view.
`void` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#endAnimation(android.view.View)(https://developer.android.com/reference/android/view/View.html view)`
Ends all animations on the view created by the `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.ItemAnimator`.
`@https://developer.android.com/reference/androidx/annotation/Nullable https://developer.android.com/reference/android/view/View.html` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#findContainingItemView(android.view.View)(@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/android/view/View.html view)`
Traverses the ancestors of the given view and returns the item view that contains it and also a direct child of the LayoutManager.
`https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutParams` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#generateLayoutParams(android.view.ViewGroup.LayoutParams)(https://developer.android.com/reference/android/view/ViewGroup.LayoutParams.html lp)`
Create a LayoutParams object suitable for this LayoutManager, copying relevant values from the supplied LayoutParams object if possible.
`https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutParams` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#generateLayoutParams(android.content.Context,android.util.AttributeSet)(https://developer.android.com/reference/android/content/Context.html c, https://developer.android.com/reference/android/util/AttributeSet.html attrs)`
Create a LayoutParams object suitable for this LayoutManager from an inflated layout resource.
`int` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#getBaseline()()`
Returns offset of the RecyclerView's text baseline from the its top boundary.
`int` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#getBottomDecorationHeight(android.view.View)(@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/android/view/View.html child)`
Returns the total height of item decorations applied to child's bottom.
`@https://developer.android.com/reference/androidx/annotation/Nullable https://developer.android.com/reference/android/view/View.html` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#getChildAt(int)(int index)`
Return the child view at the given index
`int` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#getChildCount()()`
Return the current number of child views attached to the parent RecyclerView.
`static int` `[getChildMeasureSpec](https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#getChildMeasureSpec(int,int,int,boolean))(
int parentSize,
int padding,
int childDimension,
boolean canScroll
)`
**This method is deprecated.**
use `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#getChildMeasureSpec(int,int,int,int,boolean)`
`static int` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#getChildMeasureSpec(int,int,int,int,boolean)(
int parentSize,
int parentMode,
int padding,
int childDimension,
boolean canScroll
)`
Calculate a MeasureSpec value for measuring a child view in one dimension.
`boolean` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#getClipToPadding()()`
Check if the RecyclerView is configured to clip child views to its padding.
`int` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#getColumnCountForAccessibility(androidx.recyclerview.widget.RecyclerView.Recycler,androidx.recyclerview.widget.RecyclerView.State)(
@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.Recycler recycler,
@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.State state
)`
Returns the number of columns for accessibility.
`int` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#getDecoratedBottom(android.view.View)(@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/android/view/View.html child)`
Returns the bottom edge of the given child view within its parent, offset by any applied `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.ItemDecoration`.
`void` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#getDecoratedBoundsWithMargins(android.view.View,android.graphics.Rect)(@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/android/view/View.html view, @https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/android/graphics/Rect.html outBounds)`
Returns the bounds of the view including its decoration and margins.
`int` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#getDecoratedLeft(android.view.View)(@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/android/view/View.html child)`
Returns the left edge of the given child view within its parent, offset by any applied `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.ItemDecoration`.
`int` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#getDecoratedMeasuredHeight(android.view.View)(@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/android/view/View.html child)`
Returns the measured height of the given child, plus the additional size of any insets applied by `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.ItemDecoration`.
`int` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#getDecoratedMeasuredWidth(android.view.View)(@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/android/view/View.html child)`
Returns the measured width of the given child, plus the additional size of any insets applied by `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.ItemDecoration`.
`int` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#getDecoratedRight(android.view.View)(@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/android/view/View.html child)`
Returns the right edge of the given child view within its parent, offset by any applied `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.ItemDecoration`.
`int` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#getDecoratedTop(android.view.View)(@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/android/view/View.html child)`
Returns the top edge of the given child view within its parent, offset by any applied `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.ItemDecoration`.
`@https://developer.android.com/reference/androidx/annotation/Nullable https://developer.android.com/reference/android/view/View.html` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#getFocusedChild()()`
Returns the item View which has or contains focus.
`@https://developer.android.com/reference/androidx/annotation/Px int` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#getHeight()()`
Returns the height that is currently relevant to the LayoutManager.
`int` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#getHeightMode()()`
Return the height measurement spec mode that is currently relevant to the LayoutManager.
`int` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#getItemCount()()`
Returns the number of items in the adapter bound to the parent RecyclerView.
`int` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#getItemViewType(android.view.View)(@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/android/view/View.html view)`
Returns the View type defined by the adapter.
`int` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#getLayoutDirection()()`
Returns the resolved layout direction for this RecyclerView.
`int` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#getLeftDecorationWidth(android.view.View)(@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/android/view/View.html child)`
Returns the total width of item decorations applied to child's left.
`@https://developer.android.com/reference/androidx/annotation/Px int` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#getMinimumHeight()()` `@https://developer.android.com/reference/androidx/annotation/Px int` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#getMinimumWidth()()` `@https://developer.android.com/reference/androidx/annotation/Px int` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#getPaddingBottom()()`
Return the bottom padding of the parent RecyclerView
`@https://developer.android.com/reference/androidx/annotation/Px int` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#getPaddingEnd()()`
Return the end padding of the parent RecyclerView
`@https://developer.android.com/reference/androidx/annotation/Px int` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#getPaddingLeft()()`
Return the left padding of the parent RecyclerView
`@https://developer.android.com/reference/androidx/annotation/Px int` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#getPaddingRight()()`
Return the right padding of the parent RecyclerView
`@https://developer.android.com/reference/androidx/annotation/Px int` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#getPaddingStart()()`
Return the start padding of the parent RecyclerView
`@https://developer.android.com/reference/androidx/annotation/Px int` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#getPaddingTop()()`
Return the top padding of the parent RecyclerView
`int` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#getPosition(android.view.View)(@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/android/view/View.html view)`
Returns the adapter position of the item represented by the given View.
`static https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager.Properties` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#getProperties(android.content.Context,android.util.AttributeSet,int,int)(
@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/android/content/Context.html context,
@https://developer.android.com/reference/androidx/annotation/Nullable https://developer.android.com/reference/android/util/AttributeSet.html attrs,
int defStyleAttr,
int defStyleRes
)`
Parse the xml attributes to get the most common properties used by layout managers.
`int` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#getRightDecorationWidth(android.view.View)(@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/android/view/View.html child)`
Returns the total width of item decorations applied to child's right.
`int` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#getRowCountForAccessibility(androidx.recyclerview.widget.RecyclerView.Recycler,androidx.recyclerview.widget.RecyclerView.State)(
@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.Recycler recycler,
@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.State state
)`
Returns the number of rows for accessibility.
`int` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#getSelectionModeForAccessibility(androidx.recyclerview.widget.RecyclerView.Recycler,androidx.recyclerview.widget.RecyclerView.State)(
@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.Recycler recycler,
@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.State state
)`
Returns the selection mode for accessibility.
`int` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#getTopDecorationHeight(android.view.View)(@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/android/view/View.html child)`
Returns the total height of item decorations applied to child's top.
`void` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#getTransformedBoundingBox(android.view.View,boolean,android.graphics.Rect)(
@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/android/view/View.html child,
boolean includeDecorInsets,
@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/android/graphics/Rect.html out
)`
Calculates the bounding box of the View while taking into account its matrix changes (translation, scale etc) with respect to the RecyclerView.
`@https://developer.android.com/reference/androidx/annotation/Px int` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#getWidth()()`
Returns the width that is currently relevant to the LayoutManager.
`int` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#getWidthMode()()`
Return the width measurement spec mode that is currently relevant to the LayoutManager.
`boolean` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#hasFocus()()`
Returns true if the RecyclerView this LayoutManager is bound to has or contains focus.
`void` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#ignoreView(android.view.View)(@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/android/view/View.html view)`
Flags a view so that it will not be scrapped or recycled.
`boolean` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#isAttachedToWindow()()`
Returns whether LayoutManager is currently attached to a RecyclerView which is attached to a window.
`boolean` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#isFocused()()`
Returns true if the RecyclerView this LayoutManager is bound to has focus.
`final boolean` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#isItemPrefetchEnabled()()`
Sets whether the LayoutManager should be queried for views outside of its viewport while the UI thread is idle between frames.
`boolean` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#isLayoutHierarchical(androidx.recyclerview.widget.RecyclerView.Recycler,androidx.recyclerview.widget.RecyclerView.State)(
@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.Recycler recycler,
@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.State state
)`
Returns whether layout is hierarchical or not to be used for accessibility.
`boolean` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#isMeasurementCacheEnabled()()`
In addition to the View Framework's measurement cache, RecyclerView uses its own additional measurement cache for its children to avoid re-measuring them when not necessary.
`boolean` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#isSmoothScrolling()()` `boolean` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#isViewPartiallyVisible(android.view.View,boolean,boolean)(
@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/android/view/View.html child,
boolean completelyVisible,
boolean acceptEndPointInclusion
)`
Returns whether the given child view is partially or fully visible within the padded bounded area of RecyclerView, depending on the input parameters.
`void` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#layoutDecorated(android.view.View,int,int,int,int)(
@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/android/view/View.html child,
int left,
int top,
int right,
int bottom
)`
Lay out the given child view within the RecyclerView using coordinates that include any current `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.ItemDecoration`.
`void` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#layoutDecoratedWithMargins(android.view.View,int,int,int,int)(
@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/android/view/View.html child,
int left,
int top,
int right,
int bottom
)`
Lay out the given child view within the RecyclerView using coordinates that include any current `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.ItemDecoration` and margins.
`void` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#measureChild(android.view.View,int,int)(@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/android/view/View.html child, int widthUsed, int heightUsed)`
Measure a child view using standard measurement policy, taking the padding of the parent RecyclerView and any added item decorations into account.
`void` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#measureChildWithMargins(android.view.View,int,int)(
@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/android/view/View.html child,
int widthUsed,
int heightUsed
)`
Measure a child view using standard measurement policy, taking the padding of the parent RecyclerView, any added item decorations and the child margins into account.
`void` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#moveView(int,int)(int fromIndex, int toIndex)`
Moves a View from one position to another.
`void` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#offsetChildrenHorizontal(int)(@https://developer.android.com/reference/androidx/annotation/Px int dx)`
Offset all child views attached to the parent RecyclerView by dx pixels along the horizontal axis.
`void` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#offsetChildrenVertical(int)(@https://developer.android.com/reference/androidx/annotation/Px int dy)`
Offset all child views attached to the parent RecyclerView by dy pixels along the vertical axis.
`void` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#onAdapterChanged(androidx.recyclerview.widget.RecyclerView.Adapter,androidx.recyclerview.widget.RecyclerView.Adapter)(
@https://developer.android.com/reference/androidx/annotation/Nullable https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.Adapter oldAdapter,
@https://developer.android.com/reference/androidx/annotation/Nullable https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.Adapter newAdapter
)`
Called if the RecyclerView this LayoutManager is bound to has a different adapter set via `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView#setAdapter(androidx.recyclerview.widget.RecyclerView.Adapter)` or `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView#swapAdapter(androidx.recyclerview.widget.RecyclerView.Adapter,boolean)`.
`boolean` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#onAddFocusables(androidx.recyclerview.widget.RecyclerView,java.util.ArrayList,int,int)(
@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView recyclerView,
@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/java/util/ArrayList.html views,
int direction,
int focusableMode
)`
Called to populate focusable views within the RecyclerView.
`void` `@https://developer.android.com/reference/androidx/annotation/CallSuper
https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#onAttachedToWindow(androidx.recyclerview.widget.RecyclerView)(https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView view)`
Called when this LayoutManager is both attached to a RecyclerView and that RecyclerView is attached to a window.
`void` `[onDetachedFromWindow](https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#onDetachedFromWindow(androidx.recyclerview.widget.RecyclerView))(https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView view)`
**This method is deprecated.**
override `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#onDetachedFromWindow(androidx.recyclerview.widget.RecyclerView,androidx.recyclerview.widget.RecyclerView.Recycler)`
`void` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#onInitializeAccessibilityEvent(androidx.recyclerview.widget.RecyclerView.Recycler,androidx.recyclerview.widget.RecyclerView.State,android.view.accessibility.AccessibilityEvent)(
@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.Recycler recycler,
@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.State state,
@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/android/view/accessibility/AccessibilityEvent.html event
)`
Called by the accessibility delegate to initialize an accessibility event.
`void` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#onInitializeAccessibilityNodeInfoForItem(androidx.recyclerview.widget.RecyclerView.Recycler,androidx.recyclerview.widget.RecyclerView.State,android.view.View,androidx.core.view.accessibility.AccessibilityNodeInfoCompat)(
@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.Recycler recycler,
@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.State state,
@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/android/view/View.html host,
@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/androidx/core/view/accessibility/AccessibilityNodeInfoCompat info
)`
Called by the AccessibilityDelegate when the accessibility information for a specific item should be populated.
`@https://developer.android.com/reference/androidx/annotation/Nullable https://developer.android.com/reference/android/view/View.html` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#onInterceptFocusSearch(android.view.View,int)(@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/android/view/View.html focused, int direction)`
This method gives a LayoutManager an opportunity to intercept the initial focus search before the default behavior of `https://developer.android.com/reference/android/view/FocusFinder.html` is used.
`void` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#onItemsAdded(androidx.recyclerview.widget.RecyclerView,int,int)(
@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView recyclerView,
int positionStart,
int itemCount
)`
Called when items have been added to the adapter.
`void` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#onItemsChanged(androidx.recyclerview.widget.RecyclerView)(@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView recyclerView)`
Called in response to a call to `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.Adapter#notifyDataSetChanged()` or `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView#swapAdapter(androidx.recyclerview.widget.RecyclerView.Adapter,boolean)` ()} and signals that the the entire data set has changed.
`void` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#onItemsMoved(androidx.recyclerview.widget.RecyclerView,int,int,int)(
@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView recyclerView,
int from,
int to,
int itemCount
)`
Called when an item is moved withing the adapter.
`void` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#onItemsRemoved(androidx.recyclerview.widget.RecyclerView,int,int)(
@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView recyclerView,
int positionStart,
int itemCount
)`
Called when items have been removed from the adapter.
`void` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#onItemsUpdated(androidx.recyclerview.widget.RecyclerView,int,int)(
@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView recyclerView,
int positionStart,
int itemCount
)`
Called when items have been changed in the adapter.
`void` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#onItemsUpdated(androidx.recyclerview.widget.RecyclerView,int,int,java.lang.Object)(
@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView recyclerView,
int positionStart,
int itemCount,
@https://developer.android.com/reference/androidx/annotation/Nullable https://developer.android.com/reference/java/lang/Object.html payload
)`
Called when items have been changed in the adapter and with optional payload.
`void` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#onMeasure(androidx.recyclerview.widget.RecyclerView.Recycler,androidx.recyclerview.widget.RecyclerView.State,int,int)(
@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.Recycler recycler,
@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.State state,
int widthSpec,
int heightSpec
)`
Measure the attached RecyclerView.
`boolean` `[onRequestChildFocus](https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#onRequestChildFocus(androidx.recyclerview.widget.RecyclerView,android.view.View,android.view.View))(
@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView parent,
@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/android/view/View.html child,
@https://developer.android.com/reference/androidx/annotation/Nullable https://developer.android.com/reference/android/view/View.html focused
)`
**This method is deprecated.**
Use `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#onRequestChildFocus(androidx.recyclerview.widget.RecyclerView,androidx.recyclerview.widget.RecyclerView.State,android.view.View,android.view.View)`
`boolean` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#onRequestChildFocus(androidx.recyclerview.widget.RecyclerView,androidx.recyclerview.widget.RecyclerView.State,android.view.View,android.view.View)(
@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView parent,
@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.State state,
@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/android/view/View.html child,
@https://developer.android.com/reference/androidx/annotation/Nullable https://developer.android.com/reference/android/view/View.html focused
)`
Called when a descendant view of the RecyclerView requests focus.
`void` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#onScrollStateChanged(int)(int state)`
RecyclerView calls this method to notify LayoutManager that scroll state has changed.
`boolean` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#performAccessibilityAction(androidx.recyclerview.widget.RecyclerView.Recycler,androidx.recyclerview.widget.RecyclerView.State,int,android.os.Bundle)(
@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.Recycler recycler,
@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.State state,
int action,
@https://developer.android.com/reference/androidx/annotation/Nullable https://developer.android.com/reference/android/os/Bundle.html args
)`
Called by AccessibilityDelegate when an action is requested from the RecyclerView.
`boolean` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#performAccessibilityActionForItem(androidx.recyclerview.widget.RecyclerView.Recycler,androidx.recyclerview.widget.RecyclerView.State,android.view.View,int,android.os.Bundle)(
@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.Recycler recycler,
@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.State state,
@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/android/view/View.html view,
int action,
@https://developer.android.com/reference/androidx/annotation/Nullable https://developer.android.com/reference/android/os/Bundle.html args
)`
Called by AccessibilityDelegate when an accessibility action is requested on one of the children of LayoutManager.
`void` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#postOnAnimation(java.lang.Runnable)(https://developer.android.com/reference/java/lang/Runnable.html action)`
Causes the Runnable to execute on the next animation time step.
`void` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#removeAllViews()()`
Remove all views from the currently attached RecyclerView.
`void` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#removeAndRecycleAllViews(androidx.recyclerview.widget.RecyclerView.Recycler)(@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.Recycler recycler)`
Removes all views and recycles them using the given recycler.
`void` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#removeAndRecycleView(android.view.View,androidx.recyclerview.widget.RecyclerView.Recycler)(
@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/android/view/View.html child,
@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.Recycler recycler
)`
Remove a child view and recycle it using the given Recycler.
`void` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#removeAndRecycleViewAt(int,androidx.recyclerview.widget.RecyclerView.Recycler)(
int index,
@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.Recycler recycler
)`
Remove a child view and recycle it using the given Recycler.
`boolean` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#removeCallbacks(java.lang.Runnable)(https://developer.android.com/reference/java/lang/Runnable.html action)`
Removes the specified Runnable from the message queue.
`void` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#removeDetachedView(android.view.View)(@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/android/view/View.html child)`
Finish removing a view that was previously temporarily `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#detachView(android.view.View)`.
`void` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#removeView(android.view.View)(https://developer.android.com/reference/android/view/View.html child)`
Remove a view from the currently attached RecyclerView if needed.
`void` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#removeViewAt(int)(int index)`
Remove a view from the currently attached RecyclerView if needed.
`boolean` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#requestChildRectangleOnScreen(androidx.recyclerview.widget.RecyclerView,android.view.View,android.graphics.Rect,boolean)(
@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView parent,
@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/android/view/View.html child,
@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/android/graphics/Rect.html rect,
boolean immediate
)`
Called when a child of the RecyclerView wants a particular rectangle to be positioned onto the screen.
`boolean` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#requestChildRectangleOnScreen(androidx.recyclerview.widget.RecyclerView,android.view.View,android.graphics.Rect,boolean,boolean)(
@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView parent,
@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/android/view/View.html child,
@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/android/graphics/Rect.html rect,
boolean immediate,
boolean focusedChildVisible
)`
Requests that the given child of the RecyclerView be positioned onto the screen.
`void` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#requestLayout()()`
Calls `RecyclerView#requestLayout` on the underlying RecyclerView
`void` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#requestSimpleAnimationsInNextLayout()()`
A LayoutManager can call this method to force RecyclerView to run simple animations in the next layout pass, even if there is not any trigger to do so.
`void` `[setAutoMeasureEnabled](https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#setAutoMeasureEnabled(boolean))(boolean enabled)`
**This method is deprecated.**
Implementors of LayoutManager should define whether or not it uses AutoMeasure by overriding `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#isAutoMeasureEnabled()`.
`final void` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#setItemPrefetchEnabled(boolean)(boolean enabled)`
Sets whether the LayoutManager should be queried for views outside of its viewport while the UI thread is idle between frames.
`void` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#setMeasuredDimension(int,int)(int widthSize, int heightSize)`
`https://developer.android.com/reference/android/view/View.html#setMeasuredDimension(int, int)` of the host RecyclerView.
`void` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#setMeasuredDimension(android.graphics.Rect,int,int)(https://developer.android.com/reference/android/graphics/Rect.html childrenBounds, int wSpec, int hSpec)`
Sets the measured dimensions from the given bounding box of the children and the measurement specs that were passed into `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView#onMeasure(int,int)`.
`void` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#setMeasurementCacheEnabled(boolean)(boolean measurementCacheEnabled)`
Sets whether RecyclerView should use its own measurement cache for the children.
`void` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#startSmoothScroll(androidx.recyclerview.widget.RecyclerView.SmoothScroller)(https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.SmoothScroller smoothScroller)`
Starts a smooth scroll using the provided `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.SmoothScroller`.
`void` `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#stopIgnoringView(android.view.View)(@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/android/view/View.html view)`
View can be scrapped and recycled again.
## Constants
### HORIZONTAL
Added in [1.0.0](https://developer.android.com/jetpack/androidx/releases/recyclerview#1.0.0)
```
public static final int HORIZONTAL = 0
```
### INVALID_OFFSET
Added in [1.0.0](https://developer.android.com/jetpack/androidx/releases/recyclerview#1.0.0)
```
public static final int INVALID_OFFSET = -2147483648
```
### VERTICAL
Added in [1.0.0](https://developer.android.com/jetpack/androidx/releases/recyclerview#1.0.0)
```
public static final int VERTICAL = 1
```
## Public constructors
### LinearLayoutManager
Added in [1.0.0](https://developer.android.com/jetpack/androidx/releases/recyclerview#1.0.0)
```
public LinearLayoutManager(Context context)
```
Creates a vertical LinearLayoutManager
| Parameters |
|---|---|
| `https://developer.android.com/reference/android/content/Context.html context` | Current context, will be used to access resources. |
### LinearLayoutManager
Added in [1.0.0](https://developer.android.com/jetpack/androidx/releases/recyclerview#1.0.0)
```
public LinearLayoutManager(
Context context,
int orientation,
boolean reverseLayout
)
```
| Parameters |
|---|---|
| `https://developer.android.com/reference/android/content/Context.html context` | Current context, will be used to access resources. |
| `int orientation` | Layout orientation. Should be `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#HORIZONTAL()` or `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#VERTICAL()`. |
| `boolean reverseLayout` | When set to true, layouts from end to start. |
### LinearLayoutManager
Added in [1.0.0](https://developer.android.com/jetpack/androidx/releases/recyclerview#1.0.0)
```
public LinearLayoutManager(
Context context,
AttributeSet attrs,
int defStyleAttr,
int defStyleRes
)
```
Constructor used when layout manager is set in XML by RecyclerView attribute "layoutManager". Defaults to vertical orientation. `https://developer.android.com/reference/android/R.attr.html#orientation``https://developer.android.com/reference/androidx/recyclerview/R.attr#reverseLayout()``https://developer.android.com/reference/androidx/recyclerview/R.attr#stackFromEnd()`
## Public methods
### assertNotInLayoutOrScroll
```
public void assertNotInLayoutOrScroll(String message)
```
Checks if RecyclerView is in the middle of a layout or scroll and throws an `https://developer.android.com/reference/java/lang/IllegalStateException.html` if it **is**.
| Parameters |
|---|---|
| `https://developer.android.com/reference/java/lang/String.html message` | The message for the exception. Can be null. |
| See also |
|---|---|
| `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#assertInLayoutOrScroll(java.lang.String)` | |
### canScrollHorizontally
```
public boolean canScrollHorizontally()
```
| Returns |
|---|---|
| `boolean` | true if `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#getOrientation()` is `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#HORIZONTAL()` |
### canScrollVertically
```
public boolean canScrollVertically()
```
| Returns |
|---|---|
| `boolean` | true if `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#getOrientation()` is `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#VERTICAL()` |
### collectAdjacentPrefetchPositions
```
public void collectAdjacentPrefetchPositions(
int dx,
int dy,
RecyclerView.State state,
RecyclerView.LayoutManager.LayoutPrefetchRegistry layoutPrefetchRegistry
)
```
Gather all positions from the LayoutManager to be prefetched, given specified momentum.
If item prefetch is enabled, this method is called in between traversals to gather which positions the LayoutManager will soon need, given upcoming movement in subsequent traversals.
The LayoutManager should call `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager.LayoutPrefetchRegistry#addPosition(int,int)` for each item to be prepared, and these positions will have their ViewHolders created and bound, if there is sufficient time available, in advance of being needed by a scroll or layout.
| Parameters |
|---|---|
| `int dx` | X movement component. |
| `int dy` | Y movement component. |
| `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.State state` | State of RecyclerView |
| `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager.LayoutPrefetchRegistry layoutPrefetchRegistry` | PrefetchRegistry to add prefetch entries into. |
| See also |
|---|---|
| `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#isItemPrefetchEnabled()` | |
| `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#collectInitialPrefetchPositions(int,androidx.recyclerview.widget.RecyclerView.LayoutManager.LayoutPrefetchRegistry)` | |
### collectInitialPrefetchPositions
```
public void collectInitialPrefetchPositions(
int adapterItemCount,
RecyclerView.LayoutManager.LayoutPrefetchRegistry layoutPrefetchRegistry
)
```
Gather all positions from the LayoutManager to be prefetched in preperation for its RecyclerView to come on screen, due to the movement of another, containing RecyclerView.
This method is only called when a RecyclerView is nested in another RecyclerView.
If item prefetch is enabled for this LayoutManager, as well in another containing LayoutManager, this method is called in between draw traversals to gather which positions this LayoutManager will first need, once it appears on the screen.
For example, if this LayoutManager represents a horizontally scrolling list within a vertically scrolling LayoutManager, this method would be called when the horizontal list is about to come onscreen.
The LayoutManager should call `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager.LayoutPrefetchRegistry#addPosition(int,int)` for each item to be prepared, and these positions will have their ViewHolders created and bound, if there is sufficient time available, in advance of being needed by a scroll or layout.
| Parameters |
|---|---|
| `int adapterItemCount` | number of items in the associated adapter. |
| `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager.LayoutPrefetchRegistry layoutPrefetchRegistry` | PrefetchRegistry to add prefetch entries into. |
| See also |
|---|---|
| `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#isItemPrefetchEnabled()` | |
| `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#collectAdjacentPrefetchPositions(int,int,androidx.recyclerview.widget.RecyclerView.State,androidx.recyclerview.widget.RecyclerView.LayoutManager.LayoutPrefetchRegistry)` | |
### computeHorizontalScrollExtent
```
public int computeHorizontalScrollExtent(RecyclerView.State state)
```
Override this method if you want to support scroll bars.
Read `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView#computeHorizontalScrollExtent()` for details.
Default implementation returns 0.
| Parameters |
|---|---|
| `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.State state` | Current state of RecyclerView |
| Returns |
|---|---|
| `int` | The horizontal extent of the scrollbar's thumb |
| See also |
|---|---|
| `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView#computeHorizontalScrollExtent()` | |
### computeHorizontalScrollOffset
```
public int computeHorizontalScrollOffset(RecyclerView.State state)
```
Override this method if you want to support scroll bars.
Read `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView#computeHorizontalScrollOffset()` for details.
Default implementation returns 0.
| Parameters |
|---|---|
| `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.State state` | Current State of RecyclerView where you can find total item count |
| Returns |
|---|---|
| `int` | The horizontal offset of the scrollbar's thumb |
| See also |
|---|---|
| `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView#computeHorizontalScrollOffset()` | |
### computeHorizontalScrollRange
```
public int computeHorizontalScrollRange(RecyclerView.State state)
```
Override this method if you want to support scroll bars.
Read `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView#computeHorizontalScrollRange()` for details.
Default implementation returns 0.
| Parameters |
|---|---|
| `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.State state` | Current State of RecyclerView where you can find total item count |
| Returns |
|---|---|
| `int` | The total horizontal range represented by the horizontal scrollbar |
| See also |
|---|---|
| `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView#computeHorizontalScrollRange()` | |
### computeScrollVectorForPosition
Added in [1.4.0](https://developer.android.com/jetpack/androidx/releases/recyclerview#1.4.0)
```
public PointF computeScrollVectorForPosition(int targetPosition)
```
Should calculate the vector that points to the direction where the target position can be found.
This method is used by the `https://developer.android.com/reference/androidx/recyclerview/widget/LinearSmoothScroller` to initiate a scroll towards the target position.
The magnitude of the vector is not important. It is always normalized before being used by the `https://developer.android.com/reference/androidx/recyclerview/widget/LinearSmoothScroller`.
LayoutManager should not check whether the position exists in the adapter or not.
| Parameters |
|---|---|
| `int targetPosition` | the target position to which the returned vector should point |
| Returns |
|---|---|
| `https://developer.android.com/reference/android/graphics/PointF.html` | the scroll vector for a given position. |
### computeVerticalScrollExtent
```
public int computeVerticalScrollExtent(RecyclerView.State state)
```
Override this method if you want to support scroll bars.
Read `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView#computeVerticalScrollExtent()` for details.
Default implementation returns 0.
| Parameters |
|---|---|
| `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.State state` | Current state of RecyclerView |
| Returns |
|---|---|
| `int` | The vertical extent of the scrollbar's thumb |
| See also |
|---|---|
| `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView#computeVerticalScrollExtent()` | |
### computeVerticalScrollOffset
```
public int computeVerticalScrollOffset(RecyclerView.State state)
```
Override this method if you want to support scroll bars.
Read `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView#computeVerticalScrollOffset()` for details.
Default implementation returns 0.
| Parameters |
|---|---|
| `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.State state` | Current State of RecyclerView where you can find total item count |
| Returns |
|---|---|
| `int` | The vertical offset of the scrollbar's thumb |
| See also |
|---|---|
| `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView#computeVerticalScrollOffset()` | |
### computeVerticalScrollRange
```
public int computeVerticalScrollRange(RecyclerView.State state)
```
Override this method if you want to support scroll bars.
Read `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView#computeVerticalScrollRange()` for details.
Default implementation returns 0.
| Parameters |
|---|---|
| `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.State state` | Current State of RecyclerView where you can find total item count |
| Returns |
|---|---|
| `int` | The total vertical range represented by the vertical scrollbar |
| See also |
|---|---|
| `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView#computeVerticalScrollRange()` | |
### findFirstCompletelyVisibleItemPosition
Added in [1.0.0](https://developer.android.com/jetpack/androidx/releases/recyclerview#1.0.0)
```
public int findFirstCompletelyVisibleItemPosition()
```
Returns the adapter position of the first fully visible view. This position does not include adapter changes that were dispatched after the last layout pass.
Note that bounds check is only performed in the current orientation. That means, if LayoutManager is horizontal, it will only check the view's left and right edges.
| Returns |
|---|---|
| `int` | The adapter position of the first fully visible item or `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView#NO_POSITION()` if there aren't any visible items. |
| See also |
|---|---|
| `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#findFirstVisibleItemPosition()` | |
| `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#findLastCompletelyVisibleItemPosition()` | |
### findFirstVisibleItemPosition
Added in [1.0.0](https://developer.android.com/jetpack/androidx/releases/recyclerview#1.0.0)
```
public int findFirstVisibleItemPosition()
```
Returns the adapter position of the first visible view. This position does not include adapter changes that were dispatched after the last layout pass.
Note that, this value is not affected by layout orientation or item order traversal. (`https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#setReverseLayout(boolean)`). Views are sorted by their positions in the adapter, not in the layout.
If RecyclerView has item decorators, they will be considered in calculations as well.
LayoutManager may pre-cache some views that are not necessarily visible. Those views are ignored in this method.
| Returns |
|---|---|
| `int` | The adapter position of the first visible item or `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView#NO_POSITION()` if there aren't any visible items. |
| See also |
|---|---|
| `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#findFirstCompletelyVisibleItemPosition()` | |
| `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#findLastVisibleItemPosition()` | |
### findLastCompletelyVisibleItemPosition
Added in [1.0.0](https://developer.android.com/jetpack/androidx/releases/recyclerview#1.0.0)
```
public int findLastCompletelyVisibleItemPosition()
```
Returns the adapter position of the last fully visible view. This position does not include adapter changes that were dispatched after the last layout pass.
Note that bounds check is only performed in the current orientation. That means, if LayoutManager is horizontal, it will only check the view's left and right edges.
| Returns |
|---|---|
| `int` | The adapter position of the last fully visible view or `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView#NO_POSITION()` if there aren't any visible items. |
| See also |
|---|---|
| `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#findLastVisibleItemPosition()` | |
| `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#findFirstCompletelyVisibleItemPosition()` | |
### findLastVisibleItemPosition
Added in [1.0.0](https://developer.android.com/jetpack/androidx/releases/recyclerview#1.0.0)
```
public int findLastVisibleItemPosition()
```
Returns the adapter position of the last visible view. This position does not include adapter changes that were dispatched after the last layout pass.
Note that, this value is not affected by layout orientation or item order traversal. (`https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#setReverseLayout(boolean)`). Views are sorted by their positions in the adapter, not in the layout.
If RecyclerView has item decorators, they will be considered in calculations as well.
LayoutManager may pre-cache some views that are not necessarily visible. Those views are ignored in this method.
| Returns |
|---|---|
| `int` | The adapter position of the last visible view or `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView#NO_POSITION()` if there aren't any visible items. |
| See also |
|---|---|
| `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#findLastCompletelyVisibleItemPosition()` | |
| `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#findFirstVisibleItemPosition()` | |
### findViewByPosition
```
public View findViewByPosition(int position)
```
Finds the view which represents the given adapter position.
This method traverses each child since it has no information about child order. Override this method to improve performance if your LayoutManager keeps data about child views.
If a view is ignored via #ignoreView(View), it is also ignored by this method.
### generateDefaultLayoutParams
Added in [1.4.0](https://developer.android.com/jetpack/androidx/releases/recyclerview#1.4.0)
```
public RecyclerView.LayoutParams generateDefaultLayoutParams()
```
Create a default `LayoutParams` object for a child of the RecyclerView.
LayoutManagers will often want to use a custom `LayoutParams` type to store extra information specific to the layout. Client code should subclass for this purpose.
*Important:* if you use your own custom `LayoutParams` type you must also override #checkLayoutParams(LayoutParams), #generateLayoutParams(android.view.ViewGroup.LayoutParams) and #generateLayoutParams(android.content.Context, android.util.AttributeSet).
### getInitialPrefetchItemCount
Added in [1.0.0](https://developer.android.com/jetpack/androidx/releases/recyclerview#1.0.0)
```
public int getInitialPrefetchItemCount()
```
Gets the number of items to prefetch in `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#collectInitialPrefetchPositions(int,androidx.recyclerview.widget.RecyclerView.LayoutManager.LayoutPrefetchRegistry)`, which defines how many inner items should be prefetched when this LayoutManager's RecyclerView is nested inside another RecyclerView.
| Returns |
|---|---|
| `int` | number of items to prefetch. |
| See also |
|---|---|
| `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#isItemPrefetchEnabled()` | |
| `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#setInitialPrefetchItemCount(int)` | |
| `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#collectInitialPrefetchPositions(int,androidx.recyclerview.widget.RecyclerView.LayoutManager.LayoutPrefetchRegistry)` | |
### getOrientation
Added in [1.0.0](https://developer.android.com/jetpack/androidx/releases/recyclerview#1.0.0)
```
public int getOrientation()
```
Returns the current orientation of the layout.
| Returns |
|---|---|
| `int` | Current orientation, either `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#HORIZONTAL()` or `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#VERTICAL()` |
| See also |
|---|---|
| `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#setOrientation(int)` | |
### getRecycleChildrenOnDetach
Added in [1.0.0](https://developer.android.com/jetpack/androidx/releases/recyclerview#1.0.0)
```
public boolean getRecycleChildrenOnDetach()
```
Returns whether LayoutManager will recycle its children when it is detached from RecyclerView.
| Returns |
|---|---|
| `boolean` | true if LayoutManager will recycle its children when it is detached from RecyclerView. |
### getReverseLayout
Added in [1.0.0](https://developer.android.com/jetpack/androidx/releases/recyclerview#1.0.0)
```
public boolean getReverseLayout()
```
Returns if views are laid out from the opposite direction of the layout.
| Returns |
|---|---|
| `boolean` | If layout is reversed or not. |
| See also |
|---|---|
| `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#setReverseLayout(boolean)` | |
### getStackFromEnd
Added in [1.0.0](https://developer.android.com/jetpack/androidx/releases/recyclerview#1.0.0)
```
public boolean getStackFromEnd()
```
### isAutoMeasureEnabled
```
public boolean isAutoMeasureEnabled()
```
Returns whether the measuring pass of layout should use the AutoMeasure mechanism of `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView` or if it should be done by the LayoutManager's implementation of `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#onMeasure(androidx.recyclerview.widget.RecyclerView.Recycler,androidx.recyclerview.widget.RecyclerView.State,int,int)`.
This method returns false by default (it actually returns the value passed to the deprecated `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#setAutoMeasureEnabled(boolean)`) and should be overridden to return true if a LayoutManager wants to be auto measured by the RecyclerView.
If this method is overridden to return true, `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#onMeasure(androidx.recyclerview.widget.RecyclerView.Recycler,androidx.recyclerview.widget.RecyclerView.State,int,int)` should not be overridden.
AutoMeasure is a RecyclerView mechanism that handles the measuring pass of layout in a simple and contract satisfying way, including the wrapping of children laid out by LayoutManager. Simply put, it handles wrapping children by calling `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#onLayoutChildren(androidx.recyclerview.widget.RecyclerView.Recycler,androidx.recyclerview.widget.RecyclerView.State)` during a call to `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView#onMeasure(int,int)`, and then calculating desired dimensions based on children's dimensions and positions. It does this while supporting all existing animation capabilities of the RecyclerView.
More specifically:
1. When `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView#onMeasure(int,int)` is called, if the provided measure specs both have a mode of `https://developer.android.com/reference/android/view/View.MeasureSpec.html#EXACTLY`, RecyclerView will set its measured dimensions accordingly and return, allowing layout to continue as normal (Actually, RecyclerView will call `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#onMeasure(androidx.recyclerview.widget.RecyclerView.Recycler,androidx.recyclerview.widget.RecyclerView.State,int,int)` for backwards compatibility reasons but it should not be overridden if AutoMeasure is being used).
2. If one of the layout specs is not `EXACT`, the RecyclerView will start the layout process. It will first process all pending Adapter updates and then decide whether to run a predictive layout. If it decides to do so, it will first call `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#onLayoutChildren(androidx.recyclerview.widget.RecyclerView.Recycler,androidx.recyclerview.widget.RecyclerView.State)` with `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.State#isPreLayout()` set to `true`. At this stage, `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#getWidth()` and `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#getHeight()` will still return the width and height of the RecyclerView as of the last layout calculation.
After handling the predictive case, RecyclerView will call `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#onLayoutChildren(androidx.recyclerview.widget.RecyclerView.Recycler,androidx.recyclerview.widget.RecyclerView.State)` with `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.State#isMeasuring()` set to `true` and `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.State#isPreLayout()` set to `false`. The LayoutManager can access the measurement specs via `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#getHeight()`, `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#getHeightMode()`, `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#getWidth()` and `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#getWidthMode()`.
3. After the layout calculation, RecyclerView sets the measured width \&height by calculating the bounding box for the children (+ RecyclerView's padding). The LayoutManagers can override `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#setMeasuredDimension(android.graphics.Rect,int,int)` to choose different values. For instance, GridLayoutManager overrides this value to handle the case where if it is vertical and has 3 columns but only 2 items, it should still measure its width to fit 3 items, not 2.
4. Any following calls to `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView#onMeasure(int,int)` will run `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#onLayoutChildren(androidx.recyclerview.widget.RecyclerView.Recycler,androidx.recyclerview.widget.RecyclerView.State)` with `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.State#isMeasuring()` set to `true` and `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.State#isPreLayout()` set to `false`. RecyclerView will take care of which views are actually added / removed / moved / changed for animations so that the LayoutManager should not worry about them and handle each `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#onLayoutChildren(androidx.recyclerview.widget.RecyclerView.Recycler,androidx.recyclerview.widget.RecyclerView.State)` call as if it is the last one.
5. When measure is complete and RecyclerView's `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView#onLayout(boolean,int,int,int,int)` method is called, RecyclerView checks whether it already did layout calculations during the measure pass and if so, it re-uses that information. It may still decide to call `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#onLayoutChildren(androidx.recyclerview.widget.RecyclerView.Recycler,androidx.recyclerview.widget.RecyclerView.State)` if the last measure spec was different from the final dimensions or adapter contents have changed between the measure call and the layout call.
6. Finally, animations are calculated and run as usual.
| Returns |
|---|---|
| `boolean` | `True` if the measuring pass of layout should use the AutoMeasure mechanism of `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView` or `False` if it should be done by the LayoutManager's implementation of `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#onMeasure(androidx.recyclerview.widget.RecyclerView.Recycler,androidx.recyclerview.widget.RecyclerView.State,int,int)`. |
| See also |
|---|---|
| `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#setMeasuredDimension(android.graphics.Rect,int,int)` | |
| `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#onMeasure(androidx.recyclerview.widget.RecyclerView.Recycler,androidx.recyclerview.widget.RecyclerView.State,int,int)` | |
### isLayoutReversed
```
public boolean isLayoutReversed()
```
Query if the layout is in reverse order. This will affect, for example, keyboard navigation via page up/page down. The default implementation returns false.
| Returns |
|---|---|
| `boolean` | true if this LayoutManager is currently in reverse order. |
### isSmoothScrollbarEnabled
Added in [1.0.0](https://developer.android.com/jetpack/androidx/releases/recyclerview#1.0.0)
```
public boolean isSmoothScrollbarEnabled()
```
Returns the current state of the smooth scrollbar feature. It is enabled by default.
| Returns |
|---|---|
| `boolean` | True if smooth scrollbar is enabled, false otherwise. |
| See also |
|---|---|
| `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#setSmoothScrollbarEnabled(boolean)` | |
### onDetachedFromWindow
```
public void onDetachedFromWindow(RecyclerView view, RecyclerView.Recycler recycler)
```
Called when this LayoutManager is detached from its parent RecyclerView or when its parent RecyclerView is detached from its window.
LayoutManager should clear all of its View references as another LayoutManager might be assigned to the RecyclerView.
If the RecyclerView is re-attached with the same LayoutManager and Adapter, it may not call `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#onLayoutChildren(androidx.recyclerview.widget.RecyclerView.Recycler,androidx.recyclerview.widget.RecyclerView.State)` if nothing has changed and a layout was not requested on the RecyclerView while it was detached.
If your LayoutManager has View references that it cleans in on-detach, it should also call `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView#requestLayout()` to ensure that it is re-laid out when RecyclerView is re-attached.
Subclass implementations should always call through to the superclass implementation.
| Parameters |
|---|---|
| `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView view` | The RecyclerView this LayoutManager is bound to |
| `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.Recycler recycler` | The recycler to use if you prefer to recycle your children instead of keeping them around. |
| See also |
|---|---|
| `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#onAttachedToWindow(androidx.recyclerview.widget.RecyclerView)` | |
### onFocusSearchFailed
```
public View onFocusSearchFailed(
View focused,
int direction,
RecyclerView.Recycler recycler,
RecyclerView.State state
)
```
Called when searching for a focusable view in the given direction has failed for the current content of the RecyclerView.
This is the LayoutManager's opportunity to populate views in the given direction to fulfill the request if it can. The LayoutManager should attach and return the view to be focused, if a focusable view in the given direction is found. Otherwise, if all the existing (or the newly populated views) are unfocusable, it returns the next unfocusable view to become visible on the screen. This unfocusable view is typically the first view that's either partially or fully out of RV's padded bounded area in the given direction. The default implementation returns null.
| Parameters |
|---|---|
| `https://developer.android.com/reference/android/view/View.html focused` | The currently focused view |
| `int direction` | One of `https://developer.android.com/reference/android/view/View.html#FOCUS_UP`, `https://developer.android.com/reference/android/view/View.html#FOCUS_DOWN`, `https://developer.android.com/reference/android/view/View.html#FOCUS_LEFT`, `https://developer.android.com/reference/android/view/View.html#FOCUS_RIGHT`, `https://developer.android.com/reference/android/view/View.html#FOCUS_BACKWARD`, `https://developer.android.com/reference/android/view/View.html#FOCUS_FORWARD` or 0 for not applicable |
| `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.Recycler recycler` | The recycler to use for obtaining views for currently offscreen items |
| `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.State state` | Transient state of RecyclerView |
| Returns |
|---|---|
| `https://developer.android.com/reference/android/view/View.html` | The chosen view to be focused if a focusable view is found, otherwise an unfocusable view to become visible onto the screen, else null. |
### onInitializeAccessibilityEvent
```
public void onInitializeAccessibilityEvent(AccessibilityEvent event)
```
### onInitializeAccessibilityNodeInfo
```
public void onInitializeAccessibilityNodeInfo(
@NonNull RecyclerView.Recycler recycler,
@NonNull RecyclerView.State state,
@NonNull AccessibilityNodeInfoCompat info
)
```
Called by the AccessibilityDelegate when the information about the current layout should be populated.
Default implementation adds a `https://developer.android.com/reference/androidx/core/view/accessibility/AccessibilityNodeInfoCompat.CollectionInfoCompat`.
You should override `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#getRowCountForAccessibility(androidx.recyclerview.widget.RecyclerView.Recycler,androidx.recyclerview.widget.RecyclerView.State)`, `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#getColumnCountForAccessibility(androidx.recyclerview.widget.RecyclerView.Recycler,androidx.recyclerview.widget.RecyclerView.State)`, `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#isLayoutHierarchical(androidx.recyclerview.widget.RecyclerView.Recycler,androidx.recyclerview.widget.RecyclerView.State)` and `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#getSelectionModeForAccessibility(androidx.recyclerview.widget.RecyclerView.Recycler,androidx.recyclerview.widget.RecyclerView.State)` for more accurate accessibility information.
| Parameters |
|---|---|
| `@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.Recycler recycler` | The Recycler that can be used to convert view positions into adapter positions |
| `@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.State state` | The current state of RecyclerView |
| `@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/androidx/core/view/accessibility/AccessibilityNodeInfoCompat info` | The info that should be filled by the LayoutManager |
| See also |
|---|---|
| `https://developer.android.com/reference/android/view/View.html#onInitializeAccessibilityNodeInfo(android.view.accessibility.AccessibilityNodeInfo)` | |
| `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#getRowCountForAccessibility(androidx.recyclerview.widget.RecyclerView.Recycler,androidx.recyclerview.widget.RecyclerView.State)` | |
| `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#getColumnCountForAccessibility(androidx.recyclerview.widget.RecyclerView.Recycler,androidx.recyclerview.widget.RecyclerView.State)` | |
| `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#isLayoutHierarchical(androidx.recyclerview.widget.RecyclerView.Recycler,androidx.recyclerview.widget.RecyclerView.State)` | |
| `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#getSelectionModeForAccessibility(androidx.recyclerview.widget.RecyclerView.Recycler,androidx.recyclerview.widget.RecyclerView.State)` | |
### onLayoutChildren
```
public void onLayoutChildren(
RecyclerView.Recycler recycler,
RecyclerView.State state
)
```
Lay out all relevant child views from the given adapter. The LayoutManager is in charge of the behavior of item animations. By default, RecyclerView has a non-null #getItemAnimator() ItemAnimator, and simple item animations are enabled. This means that add/remove operations on the adapter will result in animations to add new or appearing items, removed or disappearing items, and moved items. If a LayoutManager returns false from #supportsPredictiveItemAnimations(), which is the default, and runs a normal layout operation during #onLayoutChildren(Recycler, State), the RecyclerView will have enough information to run those animations in a simple way. For example, the default ItemAnimator, , will simply fade views in and out, whether they are actually added/removed or whether they are moved on or off the screen due to other add/remove operations.
A LayoutManager wanting a better item animation experience, where items can be animated onto and off of the screen according to where the items exist when they are not on screen, then the LayoutManager should return true from #supportsPredictiveItemAnimations() and add additional logic to #onLayoutChildren(Recycler, State). Supporting predictive animations means that #onLayoutChildren(Recycler, State) will be called twice; once as a "pre" layout step to determine where items would have been prior to a real layout, and again to do the "real" layout. In the pre-layout phase, items will remember their pre-layout positions to allow them to be laid out appropriately. Also, LayoutParams#isItemRemoved() removed items will be returned from the scrap to help determine correct placement of other items. These removed items should not be added to the child list, but should be used to help calculate correct positioning of other views, including views that were not previously onscreen (referred to as APPEARING views), but whose pre-layout offscreen position can be determined given the extra information about the pre-layout removed views.
The second layout pass is the real layout in which only non-removed views will be used. The only additional requirement during this pass is, if #supportsPredictiveItemAnimations() returns true, to note which views exist in the child list prior to layout and which are not there after layout (referred to as DISAPPEARING views), and to position/layout those views appropriately, without regard to the actual bounds of the RecyclerView. This allows the animation system to know the location to which to animate these disappearing views.
The default LayoutManager implementations for RecyclerView handle all of these requirements for animations already. Clients of RecyclerView can either use one of these layout managers directly or look at their implementations of onLayoutChildren() to see how they account for the APPEARING and DISAPPEARING views.
### onLayoutCompleted
```
public void onLayoutCompleted(RecyclerView.State state)
```
Called after a full layout calculation is finished. The layout calculation may include multiple `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#onLayoutChildren(androidx.recyclerview.widget.RecyclerView.Recycler,androidx.recyclerview.widget.RecyclerView.State)` calls due to animations or layout measurement but it will include only one `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#onLayoutCompleted(androidx.recyclerview.widget.RecyclerView.State)` call. This method will be called at the end of `https://developer.android.com/reference/android/view/View.html#layout(int, int, int, int)` call.
This is a good place for the LayoutManager to do some cleanup like pending scroll position, saved state etc.
| Parameters |
|---|---|
| `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.State state` | Transient state of RecyclerView |
### onRestoreInstanceState
```
public void onRestoreInstanceState(Parcelable state)
```
Called when the RecyclerView is ready to restore the state based on a previous RecyclerView. Notice that this might happen after an actual layout, based on how Adapter prefers to restore State. See `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.Adapter#getStateRestorationPolicy()` for more information.
| Parameters |
|---|---|
| `https://developer.android.com/reference/android/os/Parcelable.html state` | The parcelable that was returned by the previous LayoutManager's `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#onSaveInstanceState()` method. |
### onSaveInstanceState
```
public Parcelable onSaveInstanceState()
```
Called when the LayoutManager should save its state. This is a good time to save your scroll position, configuration and anything else that may be required to restore the same layout state if the LayoutManager is recreated.
RecyclerView does NOT verify if the LayoutManager has changed between state save and restore. This will let you share information between your LayoutManagers but it is also your responsibility to make sure they use the same parcelable class.
| Returns |
|---|---|
| `https://developer.android.com/reference/android/os/Parcelable.html` | Necessary information for LayoutManager to be able to restore its state |
### prepareForDrop
Added in [1.4.0](https://developer.android.com/jetpack/androidx/releases/recyclerview#1.4.0)
```
public void prepareForDrop(@NonNull View view, @NonNull View target, int x, int y)
```
Called by the after a View is dropped over another View.
A LayoutManager should implement this interface to get ready for the upcoming move operation.
For example, LinearLayoutManager sets up a "scrollToPositionWithOffset" calls so that the View under drag will be used as an anchor View while calculating the next layout, making layout stay consistent.
### scrollHorizontallyBy
```
public int scrollHorizontallyBy(
int dx,
RecyclerView.Recycler recycler,
RecyclerView.State state
)
```
Scroll horizontally by dx pixels in screen coordinates and return the distance traveled. The default implementation does nothing and returns 0.
### scrollToPosition
```
public void scrollToPosition(int position)
```
Scroll the RecyclerView to make the position visible.
RecyclerView will scroll the minimum amount that is necessary to make the target position visible. If you are looking for a similar behavior to `https://developer.android.com/reference/android/widget/ListView.html#setSelection(int)` or `https://developer.android.com/reference/android/widget/AbsListView.html#setSelectionFromTop(int, int)`, use `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#scrollToPositionWithOffset(int,int)`.
Note that scroll position change will not be reflected until the next layout call.
| Parameters |
|---|---|
| `int position` | Scroll to this adapter position |
| See also |
|---|---|
| `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#scrollToPositionWithOffset(int,int)` | |
### scrollToPositionWithOffset
Added in [1.0.0](https://developer.android.com/jetpack/androidx/releases/recyclerview#1.0.0)
```
public void scrollToPositionWithOffset(int position, int offset)
```
Scroll to the specified adapter position with the given offset from resolved layout start. Resolved layout start depends on `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#getReverseLayout()`, `https://developer.android.com/reference/androidx/core/view/ViewCompat#getLayoutDirection(android.view.View)` and `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#getStackFromEnd()`.
For example, if layout is `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#VERTICAL()` and `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#getStackFromEnd()` is true, calling `scrollToPositionWithOffset(10, 20)` will layout such that `item[10]`'s bottom is 20 pixels above the RecyclerView's bottom.
Note that scroll position change will not be reflected until the next layout call.
If you are just trying to make a position visible, use `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#scrollToPosition(int)`.
| Parameters |
|---|---|
| `int position` | Index (starting at 0) of the reference item. |
| `int offset` | The distance (in pixels) between the start edge of the item view and start edge of the RecyclerView. |
| See also |
|---|---|
| `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#setReverseLayout(boolean)` | |
| `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#scrollToPosition(int)` | |
### scrollVerticallyBy
```
public int scrollVerticallyBy(
int dy,
RecyclerView.Recycler recycler,
RecyclerView.State state
)
```
Scroll vertically by dy pixels in screen coordinates and return the distance traveled. The default implementation does nothing and returns 0.
### setInitialPrefetchItemCount
Added in [1.0.0](https://developer.android.com/jetpack/androidx/releases/recyclerview#1.0.0)
```
public void setInitialPrefetchItemCount(int itemCount)
```
Sets the number of items to prefetch in `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#collectInitialPrefetchPositions(int,androidx.recyclerview.widget.RecyclerView.LayoutManager.LayoutPrefetchRegistry)`, which defines how many inner items should be prefetched when this LayoutManager's RecyclerView is nested inside another RecyclerView.
Set this value to the number of items this inner LayoutManager will display when it is first scrolled into the viewport. RecyclerView will attempt to prefetch that number of items so they are ready, avoiding jank as the inner RecyclerView is scrolled into the viewport.
For example, take a vertically scrolling RecyclerView with horizontally scrolling inner RecyclerViews. The rows always have 4 items visible in them (or 5 if not aligned). Passing `4` to this method for each inner RecyclerView's LinearLayoutManager will enable RecyclerView's prefetching feature to do create/bind work for 4 views within a row early, before it is scrolled on screen, instead of just the default 2.
Calling this method does nothing unless the LayoutManager is in a RecyclerView nested in another RecyclerView.
**Note:** Setting this value to be larger than the number of views that will be visible in this view can incur unnecessary bind work, and an increase to the number of Views created and in active use.
| Parameters |
|---|---|
| `int itemCount` | Number of items to prefetch |
| See also |
|---|---|
| `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#isItemPrefetchEnabled()` | |
| `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#getInitialPrefetchItemCount()` | |
| `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#collectInitialPrefetchPositions(int,androidx.recyclerview.widget.RecyclerView.LayoutManager.LayoutPrefetchRegistry)` | |
### setOrientation
Added in [1.0.0](https://developer.android.com/jetpack/androidx/releases/recyclerview#1.0.0)
```
public void setOrientation(int orientation)
```
Sets the orientation of the layout. `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager` will do its best to keep scroll position.
| Parameters |
|---|---|
| `int orientation` | `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#HORIZONTAL()` or `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#VERTICAL()` |
### setRecycleChildrenOnDetach
Added in [1.0.0](https://developer.android.com/jetpack/androidx/releases/recyclerview#1.0.0)
```
public void setRecycleChildrenOnDetach(boolean recycleChildrenOnDetach)
```
Set whether LayoutManager will recycle its children when it is detached from RecyclerView.
If you are using a `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.RecycledViewPool`, it might be a good idea to set this flag to `true` so that views will be available to other RecyclerViews immediately.
Note that, setting this flag will result in a performance drop if RecyclerView is restored.
| Parameters |
|---|---|
| `boolean recycleChildrenOnDetach` | Whether children should be recycled in detach or not. |
### setReverseLayout
Added in [1.0.0](https://developer.android.com/jetpack/androidx/releases/recyclerview#1.0.0)
```
public void setReverseLayout(boolean reverseLayout)
```
Used to reverse item traversal and layout order. This behaves similar to the layout change for RTL views. When set to true, first item is laid out at the end of the UI, second item is laid out before it etc. For horizontal layouts, it depends on the layout direction. When set to true, If `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView` is LTR, than it will layout from RTL, if `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView`} is RTL, it will layout from LTR. If you are looking for the exact same behavior of `https://developer.android.com/reference/android/widget/AbsListView.html#setStackFromBottom(boolean)`, use `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#setStackFromEnd(boolean)`
### setSmoothScrollbarEnabled
Added in [1.0.0](https://developer.android.com/jetpack/androidx/releases/recyclerview#1.0.0)
```
public void setSmoothScrollbarEnabled(boolean enabled)
```
When smooth scrollbar is enabled, the position and size of the scrollbar thumb is computed based on the number of visible pixels in the visible items. This however assumes that all list items have similar or equal widths or heights (depending on list orientation). If you use a list in which items have different dimensions, the scrollbar will change appearance as the user scrolls through the list. To avoid this issue, you need to disable this property. When smooth scrollbar is disabled, the position and size of the scrollbar thumb is based solely on the number of items in the adapter and the position of the visible items inside the adapter. This provides a stable scrollbar as the user navigates through a list of items with varying widths / heights.
| Parameters |
|---|---|
| `boolean enabled` | Whether or not to enable smooth scrollbar. |
| See also |
|---|---|
| `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#setSmoothScrollbarEnabled(boolean)` | |
### setStackFromEnd
Added in [1.0.0](https://developer.android.com/jetpack/androidx/releases/recyclerview#1.0.0)
```
public void setStackFromEnd(boolean stackFromEnd)
```
Compatibility support for `https://developer.android.com/reference/android/widget/AbsListView.html#setStackFromBottom(boolean)`
### smoothScrollToPosition
```
public void smoothScrollToPosition(
RecyclerView recyclerView,
RecyclerView.State state,
int position
)
```
Smooth scroll to the specified adapter position.
To support smooth scrolling, override this method, create your `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.SmoothScroller` instance and call `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#startSmoothScroll(androidx.recyclerview.widget.RecyclerView.SmoothScroller)`.
| Parameters |
|---|---|
| `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView recyclerView` | The RecyclerView to which this layout manager is attached |
| `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.State state` | Current State of RecyclerView |
| `int position` | Scroll to this adapter position. |
### supportsPredictiveItemAnimations
```
public boolean supportsPredictiveItemAnimations()
```
Returns whether this LayoutManager supports "predictive item animations".
"Predictive item animations" are automatically created animations that show where items came from, and where they are going to, as items are added, removed, or moved within a layout.
A LayoutManager wishing to support predictive item animations must override this method to return true (the default implementation returns false) and must obey certain behavioral contracts outlined in `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#onLayoutChildren(androidx.recyclerview.widget.RecyclerView.Recycler,androidx.recyclerview.widget.RecyclerView.State)`.
Whether item animations actually occur in a RecyclerView is actually determined by both the return value from this method and the `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView#setItemAnimator(androidx.recyclerview.widget.RecyclerView.ItemAnimator)` set on the RecyclerView itself. If the RecyclerView has a non-null ItemAnimator but this method returns false, then only "simple item animations" will be enabled in the RecyclerView, in which views whose position are changing are simply faded in/out. If the RecyclerView has a non-null ItemAnimator and this method returns true, then predictive item animations will be enabled in the RecyclerView.
| Returns |
|---|---|
| `boolean` | true if this LayoutManager supports predictive item animations, false otherwise. |
## Protected methods
### calculateExtraLayoutSpace
Added in [1.1.0](https://developer.android.com/jetpack/androidx/releases/recyclerview#1.1.0)
```
protected void calculateExtraLayoutSpace(
@NonNull RecyclerView.State state,
@NonNull int[] extraLayoutSpace
)
```
Calculates the amount of extra space (in pixels) that should be laid out by `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager` and stores the result in `extraLayoutSpace`. ` extraLayoutSpace[0]` should be used for the extra space at the top/left, and ` extraLayoutSpace[1]` should be used for the extra space at the bottom/right (depending on the orientation). Thus, the side where it is applied is unaffected by `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.LayoutManager#getLayoutDirection()` (LTR vs RTL), `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#getStackFromEnd()` and `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#getReverseLayout()`. Negative values are ignored.
By default, `LinearLayoutManager` lays out 1 extra page of items while smooth scrolling, in the direction of the scroll, and no extra space is laid out in all other situations. You can override this method to implement your own custom pre-cache logic. Use `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.State#hasTargetScrollPosition()` to find out if a smooth scroll to a position is in progress, and `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.State#getTargetScrollPosition()` to find out which item it is scrolling to.
**Note:**Laying out extra items generally comes with significant performance cost. It's typically only desirable in places like smooth scrolling to an unknown location, where 1) the extra content helps LinearLayoutManager know in advance when its target is approaching, so it can decelerate early and smoothly and 2) while motion is continuous.
Extending the extra layout space is especially expensive if done while the user may change scrolling direction. In the default implementation, changing direction will cause the extra layout space to swap to the opposite side of the viewport, incurring many rebinds/recycles, unless the cache is large enough to handle it.
### getExtraLayoutSpace
Added in [1.0.0](https://developer.android.com/jetpack/androidx/releases/recyclerview#1.0.0) Deprecated in [1.1.0](https://developer.android.com/jetpack/androidx/releases/recyclerview#1.1.0)
```
protected int [getExtraLayoutSpace](https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#getExtraLayoutSpace(androidx.recyclerview.widget.RecyclerView.State))(RecyclerView.State state)
```
> [!CAUTION]
> **This method is deprecated.**
>
> Use `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager#calculateExtraLayoutSpace(androidx.recyclerview.widget.RecyclerView.State,int[])` instead.
Returns the amount of extra space that should be laid out by LayoutManager.
By default, `https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager` lays out 1 extra page of items while smooth scrolling and 0 otherwise. You can override this method to implement your custom layout pre-cache logic.
**Note:**Laying out invisible elements generally comes with significant performance cost. It's typically only desirable in places like smooth scrolling to an unknown location, where 1) the extra content helps LinearLayoutManager know in advance when its target is approaching, so it can decelerate early and smoothly and 2) while motion is continuous.
Extending the extra layout space is especially expensive if done while the user may change scrolling direction. Changing direction will cause the extra layout space to swap to the opposite side of the viewport, incurring many rebinds/recycles, unless the cache is large enough to handle it.
| Returns |
|---|---|
| `int` | The extra space that should be laid out (in pixels). |
### isLayoutRTL
Added in [1.0.0](https://developer.android.com/jetpack/androidx/releases/recyclerview#1.0.0)
```
protected boolean isLayoutRTL()
```