LayoutManager

Kotlin |Java

abstract class LayoutManager

kotlin.Any
↳	androidx.recyclerview.widget.RecyclerView.LayoutManager

Known Direct Subclasses

LinearLayoutManager, StaggeredGridLayoutManager

LinearLayoutManager	A `RecyclerView.LayoutManager` implementation which provides similar functionality to `android.widget.ListView`.
StaggeredGridLayoutManager	A LayoutManager that lays out children in a staggered grid formation.

Known Indirect Subclasses

GridLayoutManager, WearableLinearLayoutManager

GridLayoutManager	A `RecyclerView.LayoutManager` implementations that lays out items in a grid.
WearableLinearLayoutManager	This wear-specific implementation of `LinearLayoutManager` provides basic offsetting logic for updating child layout.

A LayoutManager is responsible for measuring and positioning item views within a RecyclerView as well as determining the policy for when to recycle item views that are no longer visible to the user. By changing the LayoutManager a RecyclerView can be used to implement a standard vertically scrolling list, a uniform grid, staggered grids, horizontally scrolling collections and more. Several stock layout managers are provided for general use.

If the LayoutManager specifies a default constructor or one with the signature (Context, AttributeSet, int, int), RecyclerView will instantiate and set the LayoutManager when being inflated. Most used properties can be then obtained from getProperties(Context, AttributeSet, int, int). In case a LayoutManager specifies both constructors, the non-default constructor will take precedence.

Summary

Nested classes
abstract	`LayoutPrefetchRegistry` Interface for LayoutManagers to request items to be prefetched, based on position, with specified distance from viewport, which indicates priority.
open	`Properties` Some general properties that a LayoutManager may want to use.

Public constructors
`<init>()` A `LayoutManager` is responsible for measuring and positioning item views within a `RecyclerView` as well as determining the policy for when to recycle item views that are no longer visible to the user.

Public methods
open Unit	`addDisappearingView(child: View!)` To be called only during `onLayoutChildren(Recycler, State)` to add a view to the layout that is known to be going away, either because it has been `removed` 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.
open Unit	`addDisappearingView(child: View!, index: Int)` To be called only during `onLayoutChildren(Recycler, State)` to add a view to the layout that is known to be going away, either because it has been `removed` 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.
open Unit	`addView(child: View!)` Add a view to the currently attached RecyclerView if needed.
open Unit	`addView(child: View!, index: Int)` Add a view to the currently attached RecyclerView if needed.
open Unit	`assertInLayoutOrScroll(message: String!)` Checks if RecyclerView is in the middle of a layout or scroll and throws an `IllegalStateException` if it is not.
open Unit	`assertNotInLayoutOrScroll(message: String!)` Checks if RecyclerView is in the middle of a layout or scroll and throws an `IllegalStateException` if it is.
open Unit	`attachView(@NonNull child: View, index: Int, lp: RecyclerView.LayoutParams!)` Reattach a previously `detached` view.
open Unit	`attachView(@NonNull child: View, index: Int)` Reattach a previously `detached` view.
open Unit	`attachView(@NonNull child: View)` Reattach a previously `detached` view.
open Unit	`calculateItemDecorationsForChild(@NonNull child: View, @NonNull outRect: Rect)` Calculates the item decor insets applied to the given child and updates the provided Rect instance with the inset values.
open Boolean	`canScrollHorizontally()` Query if horizontal scrolling is currently supported.
open Boolean	`canScrollVertically()` Query if vertical scrolling is currently supported.
open Boolean	`checkLayoutParams(lp: RecyclerView.LayoutParams!)` Determines the validity of the supplied LayoutParams object.
open static Int	`chooseSize(spec: Int, desired: Int, min: Int)` Chooses a size from the given specs and parameters that is closest to the desired size and also complies with the spec.
open Unit	`collectAdjacentPrefetchPositions(dx: Int, dy: Int, state: RecyclerView.State!, layoutPrefetchRegistry: RecyclerView.LayoutManager.LayoutPrefetchRegistry!)` Gather all positions from the LayoutManager to be prefetched, given specified momentum.
open Unit	`collectInitialPrefetchPositions(adapterItemCount: Int, layoutPrefetchRegistry: RecyclerView.LayoutManager.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.
open Int	`computeHorizontalScrollExtent(@NonNull state: RecyclerView.State)` Override this method if you want to support scroll bars.
open Int	`computeHorizontalScrollOffset(@NonNull state: RecyclerView.State)` Override this method if you want to support scroll bars.
open Int	`computeHorizontalScrollRange(@NonNull state: RecyclerView.State)` Override this method if you want to support scroll bars.
open Int	`computeVerticalScrollExtent(@NonNull state: RecyclerView.State)` Override this method if you want to support scroll bars.
open Int	`computeVerticalScrollOffset(@NonNull state: RecyclerView.State)` Override this method if you want to support scroll bars.
open Int	`computeVerticalScrollRange(@NonNull state: RecyclerView.State)` Override this method if you want to support scroll bars.
open Unit	`detachAndScrapAttachedViews(@NonNull recycler: RecyclerView.Recycler)` Temporarily detach and scrap all currently attached child views.
open Unit	`detachAndScrapView(@NonNull child: View, @NonNull recycler: RecyclerView.Recycler)` Detach a child view and add it to a `Recycler's` scrap heap.
open Unit	`detachAndScrapViewAt(index: Int, @NonNull recycler: RecyclerView.Recycler)` Detach a child view and add it to a `Recycler's` scrap heap.
open Unit	`detachView(@NonNull child: View)` Temporarily detach a child view.
open Unit	`detachViewAt(index: Int)` Temporarily detach a child view.
open Unit	`endAnimation(view: View!)` Ends all animations on the view created by the `ItemAnimator`.
open View?	`findContainingItemView(@NonNull view: View)` Traverses the ancestors of the given view and returns the item view that contains it and also a direct child of the LayoutManager.
open View?	`findViewByPosition(position: Int)` Finds the view which represents the given adapter position.
abstract RecyclerView.LayoutParams!	`generateDefaultLayoutParams()` Create a default `LayoutParams` object for a child of the RecyclerView.
open RecyclerView.LayoutParams!	`generateLayoutParams(lp: LayoutParams!)` Create a LayoutParams object suitable for this LayoutManager, copying relevant values from the supplied LayoutParams object if possible.
open RecyclerView.LayoutParams!	`generateLayoutParams(c: Context!, attrs: AttributeSet!)` Create a LayoutParams object suitable for this LayoutManager from an inflated layout resource.
open Int	`getBaseline()` Returns offset of the RecyclerView's text baseline from the its top boundary.
open Int	`getBottomDecorationHeight(@NonNull child: View)` Returns the total height of item decorations applied to child's bottom.
open View?	`getChildAt(index: Int)` Return the child view at the given index
open Int	`getChildCount()` Return the current number of child views attached to the parent RecyclerView.
open static Int	`getChildMeasureSpec(parentSize: Int, padding: Int, childDimension: Int, canScroll: Boolean)` Calculate a MeasureSpec value for measuring a child view in one dimension.
open static Int	`getChildMeasureSpec(parentSize: Int, parentMode: Int, padding: Int, childDimension: Int, canScroll: Boolean)` Calculate a MeasureSpec value for measuring a child view in one dimension.
open Boolean	`getClipToPadding()` Check if the RecyclerView is configured to clip child views to its padding.
open Int	`getColumnCountForAccessibility(@NonNull recycler: RecyclerView.Recycler, @NonNull state: RecyclerView.State)` Returns the number of columns for accessibility.
open Int	`getDecoratedBottom(@NonNull child: View)` Returns the bottom edge of the given child view within its parent, offset by any applied `ItemDecorations`.
open Unit	`getDecoratedBoundsWithMargins(@NonNull view: View, @NonNull outBounds: Rect)` Returns the bounds of the view including its decoration and margins.
open Int	`getDecoratedLeft(@NonNull child: View)` Returns the left edge of the given child view within its parent, offset by any applied `ItemDecorations`.
open Int	`getDecoratedMeasuredHeight(@NonNull child: View)` Returns the measured height of the given child, plus the additional size of any insets applied by `ItemDecorations`.
open Int	`getDecoratedMeasuredWidth(@NonNull child: View)` Returns the measured width of the given child, plus the additional size of any insets applied by `ItemDecorations`.
open Int	`getDecoratedRight(@NonNull child: View)` Returns the right edge of the given child view within its parent, offset by any applied `ItemDecorations`.
open Int	`getDecoratedTop(@NonNull child: View)` Returns the top edge of the given child view within its parent, offset by any applied `ItemDecorations`.
open View?	`getFocusedChild()` Returns the item View which has or contains focus.
open Int	`getHeight()` Returns the height that is currently relevant to the LayoutManager.
open Int	`getHeightMode()` Return the height measurement spec mode that is currently relevant to the LayoutManager.
open Int	`getItemCount()` Returns the number of items in the adapter bound to the parent RecyclerView.
open Int	`getItemViewType(@NonNull view: View)` Returns the View type defined by the adapter.
open Int	`getLayoutDirection()` Returns the resolved layout direction for this RecyclerView.
open Int	`getLeftDecorationWidth(@NonNull child: View)` Returns the total width of item decorations applied to child's left.
open Int	`getMinimumHeight()`
open Int	`getMinimumWidth()`
open Int	`getPaddingBottom()` Return the bottom padding of the parent RecyclerView
open Int	`getPaddingEnd()` Return the end padding of the parent RecyclerView
open Int	`getPaddingLeft()` Return the left padding of the parent RecyclerView
open Int	`getPaddingRight()` Return the right padding of the parent RecyclerView
open Int	`getPaddingStart()` Return the start padding of the parent RecyclerView
open Int	`getPaddingTop()` Return the top padding of the parent RecyclerView
open Int	`getPosition(@NonNull view: View)` Returns the adapter position of the item represented by the given View.
open static RecyclerView.LayoutManager.Properties!	`getProperties(@NonNull context: Context, @Nullable attrs: AttributeSet?, defStyleAttr: Int, defStyleRes: Int)` Parse the xml attributes to get the most common properties used by layout managers.
open Int	`getRightDecorationWidth(@NonNull child: View)` Returns the total width of item decorations applied to child's right.
open Int	`getRowCountForAccessibility(@NonNull recycler: RecyclerView.Recycler, @NonNull state: RecyclerView.State)` Returns the number of rows for accessibility.
open Int	`getSelectionModeForAccessibility(@NonNull recycler: RecyclerView.Recycler, @NonNull state: RecyclerView.State)` Returns the selection mode for accessibility.
open Int	`getTopDecorationHeight(@NonNull child: View)` Returns the total height of item decorations applied to child's top.
open Unit	`getTransformedBoundingBox(@NonNull child: View, includeDecorInsets: Boolean, @NonNull out: Rect)` Calculates the bounding box of the View while taking into account its matrix changes (translation, scale etc) with respect to the RecyclerView.
open Int	`getWidth()` Returns the width that is currently relevant to the LayoutManager.
open Int	`getWidthMode()` Return the width measurement spec mode that is currently relevant to the LayoutManager.
open Boolean	`hasFocus()` Returns true if the RecyclerView this LayoutManager is bound to has or contains focus.
open Unit	`ignoreView(@NonNull view: View)` Flags a view so that it will not be scrapped or recycled.
open Boolean	`isAttachedToWindow()` Returns whether LayoutManager is currently attached to a RecyclerView which is attached to a window.
open Boolean	`isAutoMeasureEnabled()` Returns whether the measuring pass of layout should use the AutoMeasure mechanism of `RecyclerView` or if it should be done by the LayoutManager's implementation of `LayoutManager#onMeasure(Recycler, State, int, int)`.
open Boolean	`isFocused()` Returns true if the RecyclerView this LayoutManager is bound to has focus.
Boolean	`isItemPrefetchEnabled()` Sets whether the LayoutManager should be queried for views outside of its viewport while the UI thread is idle between frames.
open Boolean	`isLayoutHierarchical(@NonNull recycler: RecyclerView.Recycler, @NonNull state: RecyclerView.State)` Returns whether layout is hierarchical or not to be used for accessibility.
open Boolean	`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.
open Boolean	`isSmoothScrolling()`
open Boolean	`isViewPartiallyVisible(@NonNull child: View, completelyVisible: Boolean, acceptEndPointInclusion: Boolean)` Returns whether the given child view is partially or fully visible within the padded bounded area of RecyclerView, depending on the input parameters.
open Unit	`layoutDecorated(@NonNull child: View, left: Int, top: Int, right: Int, bottom: Int)` Lay out the given child view within the RecyclerView using coordinates that include any current `ItemDecorations`.
open Unit	`layoutDecoratedWithMargins(@NonNull child: View, left: Int, top: Int, right: Int, bottom: Int)` Lay out the given child view within the RecyclerView using coordinates that include any current `ItemDecorations` and margins.
open Unit	`measureChild(@NonNull child: View, widthUsed: Int, heightUsed: Int)` Measure a child view using standard measurement policy, taking the padding of the parent RecyclerView and any added item decorations into account.
open Unit	`measureChildWithMargins(@NonNull child: View, widthUsed: Int, heightUsed: Int)` 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.
open Unit	`moveView(fromIndex: Int, toIndex: Int)` Moves a View from one position to another.
open Unit	`offsetChildrenHorizontal(@Px dx: Int)` Offset all child views attached to the parent RecyclerView by dx pixels along the horizontal axis.
open Unit	`offsetChildrenVertical(@Px dy: Int)` Offset all child views attached to the parent RecyclerView by dy pixels along the vertical axis.
open Unit	`onAdapterChanged(@Nullable oldAdapter: RecyclerView.Adapter<RecyclerView.ViewHolder!>?, @Nullable newAdapter: RecyclerView.Adapter<RecyclerView.ViewHolder!>?)` Called if the RecyclerView this LayoutManager is bound to has a different adapter set via `RecyclerView#setAdapter(Adapter)` or `RecyclerView#swapAdapter(Adapter, boolean)`.
open Boolean	`onAddFocusables(@NonNull recyclerView: RecyclerView, @NonNull views: ArrayList<View!>, direction: Int, focusableMode: Int)` Called to populate focusable views within the RecyclerView.
open Unit	`onAttachedToWindow(view: RecyclerView!)` Called when this LayoutManager is both attached to a RecyclerView and that RecyclerView is attached to a window.
open Unit	`onDetachedFromWindow(view: RecyclerView!)`
open Unit	`onDetachedFromWindow(view: RecyclerView!, recycler:`