GridLayoutManager


public class GridLayoutManager extends LinearLayoutManager


A RecyclerView.LayoutManager implementations that lays out items in a grid.

By default, each item occupies 1 span. You can change it by providing a custom SpanSizeLookup instance via setSpanSizeLookup.

Summary

Nested types

Default implementation for SpanSizeLookup.

LayoutParams used by GridLayoutManager.

public abstract class GridLayoutManager.SpanSizeLookup

A helper class to provide the number of spans each item occupies.

Constants

static final int

Public constructors

GridLayoutManager(Context context, int spanCount)

Creates a vertical GridLayoutManager

GridLayoutManager(
    Context context,
    AttributeSet attrs,
    int defStyleAttr,
    int defStyleRes
)

Constructor used when layout manager is set in XML by RecyclerView attribute "layoutManager".

GridLayoutManager(
    Context context,
    int spanCount,
    int orientation,
    boolean reverseLayout
)

Public methods

boolean

Determines the validity of the supplied LayoutParams object.

int

Override this method if you want to support scroll bars.

int

Override this method if you want to support scroll bars.

int

Override this method if you want to support scroll bars.

int

Override this method if you want to support scroll bars.

RecyclerView.LayoutParams

Create a default LayoutParams object for a child of the RecyclerView.

RecyclerView.LayoutParams

Create a LayoutParams object suitable for this LayoutManager, copying relevant values from the supplied LayoutParams object if possible.

RecyclerView.LayoutParams

Create a LayoutParams object suitable for this LayoutManager from an inflated layout resource.

int

Returns the number of columns for accessibility.

int

Returns the number of rows for accessibility.

int

Returns the number of spans laid out by this grid.

GridLayoutManager.SpanSizeLookup

Returns the current SpanSizeLookup used by the GridLayoutManager.

boolean

Returns true if the scroll offset and scroll range calculations take account of span information.

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.

void

Called by the AccessibilityDelegate when the information about the current layout should be populated.

void

Called by the AccessibilityDelegate when the accessibility information for a specific item should be populated.

void
onItemsAdded(
    RecyclerView recyclerView,
    int positionStart,
    int itemCount
)

Called when items have been added to the adapter.

void

Called in response to a call to notifyDataSetChanged or swapAdapter ()} and signals that the the entire data set has changed.

void
onItemsMoved(RecyclerView recyclerView, int from, int to, int itemCount)

Called when an item is moved withing the adapter.

void
onItemsRemoved(
    RecyclerView recyclerView,
    int positionStart,
    int itemCount
)

Called when items have been removed from the adapter.

void
onItemsUpdated(
    RecyclerView recyclerView,
    int positionStart,
    int itemCount,
    Object payload
)

Called when items have been changed in the adapter and with optional payload.

void

Lay out all relevant child views from the given adapter.

void

Called after a full layout calculation is finished.

int
scrollHorizontallyBy(
    int dx,
    RecyclerView.Recycler recycler,
    RecyclerView.State state
)

Scroll horizontally by dx pixels in screen coordinates and return the distance traveled.

int
scrollVerticallyBy(
    int dy,
    RecyclerView.Recycler recycler,
    RecyclerView.State state
)

Scroll vertically by dy pixels in screen coordinates and return the distance traveled.

void
setMeasuredDimension(Rect 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 onMeasure.

void
setSpanCount(int spanCount)

Sets the number of spans to be laid out.

void

Sets the source to get the number of spans occupied by each item in the adapter.

void
setStackFromEnd(boolean stackFromEnd)

stackFromEnd is not supported by GridLayoutManager.

void
setUsingSpansToEstimateScrollbarDimensions(
    boolean useSpansToEstimateScrollBarDimensions
)

When this flag is set, the scroll offset and scroll range calculations will take account of span information.

boolean

Returns whether this LayoutManager supports "predictive item animations".

Inherited Constants

From androidx.recyclerview.widget.LinearLayoutManager
static final int
static final int
INVALID_OFFSET = -2147483648
static final int

Inherited methods

From androidx.recyclerview.widget.LinearLayoutManager
void

Checks if RecyclerView is in the middle of a layout or scroll and throws an IllegalStateException if it is.

void
calculateExtraLayoutSpace(
    @NonNull RecyclerView.State state,
    @NonNull int[] extraLayoutSpace
)

Calculates the amount of extra space (in pixels) that should be laid out by and stores the result in extraLayoutSpace.

boolean
boolean
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.

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.

int

Override this method if you want to support scroll bars.

PointF
computeScrollVectorForPosition(int targetPosition)

Should calculate the vector that points to the direction where the target position can be found.

int

Override this method if you want to support scroll bars.

int

Returns the adapter position of the first fully visible view.

int

Returns the adapter position of the first visible view.

int

Returns the adapter position of the last fully visible view.

int

Returns the adapter position of the last visible view.

View
findViewByPosition(int position)

Finds the view which represents the given adapter position.

int

This method is deprecated.

Use calculateExtraLayoutSpace instead.

int

Gets the number of items to prefetch in collectInitialPrefetchPositions, which defines how many inner items should be prefetched when this LayoutManager's RecyclerView is nested inside another RecyclerView.

int

Returns the current orientation of the layout.

boolean

Returns whether LayoutManager will recycle its children when it is detached from RecyclerView.

boolean

Returns if views are laid out from the opposite direction of the layout.

boolean
boolean

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 onMeasure.

boolean
boolean

Query if the layout is in reverse order.

boolean

Returns the current state of the smooth scrollbar feature.

void

Called when this LayoutManager is detached from its parent RecyclerView or when its parent RecyclerView is detached from its window.

void
void

Called when the RecyclerView is ready to restore the state based on a previous RecyclerView.

Parcelable

Called when the LayoutManager should save its state.

void
prepareForDrop(@NonNull View view, @NonNull View target, int x, int y)

Called by the after a View is dropped over another View.

void
scrollToPosition(int position)

Scroll the RecyclerView to make the position visible.

void
scrollToPositionWithOffset(int position, int offset)

Scroll to the specified adapter position with the given offset from resolved layout start.

void

Sets the number of items to prefetch in collectInitialPrefetchPositions, which defines how many inner items should be prefetched when this LayoutManager's RecyclerView is nested inside another RecyclerView.

void
setOrientation(int orientation)

Sets the orientation of the layout.

void
setRecycleChildrenOnDetach(boolean recycleChildrenOnDetach)

Set whether LayoutManager will recycle its children when it is detached from RecyclerView.

void
setReverseLayout(boolean reverseLayout)

Used to reverse item traversal and layout order.

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.

void
smoothScrollToPosition(
    RecyclerView recyclerView,
    RecyclerView.State state,
    int position
)

Smooth scroll to the specified adapter position.

From androidx.recyclerview.widget.RecyclerView.LayoutManager
void

To be called only during onLayoutChildren 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.

void
addDisappearingView(View child, int index)

To be called only during onLayoutChildren 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.

void
addView(View child)

Add a view to the currently attached RecyclerView if needed.

void
addView(View child, int index)

Add a view to the currently attached RecyclerView if needed.

void

Checks if RecyclerView is in the middle of a layout or scroll and throws an IllegalStateException if it is not.

void

Reattach a previously detached view.

void
attachView(@NonNull View child, int index)

Reattach a previously detached view.

void
attachView(@NonNull View child, int index, RecyclerView.LayoutParams lp)

Reattach a previously detached view.

void
calculateItemDecorationsForChild(
    @NonNull View child,
    @NonNull Rect outRect
)

Calculates the item decor insets applied to the given child and updates the provided Rect instance with the inset values.

static int
chooseSize(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
collectAdjacentPrefetchPositions(
    int dx,
    int dy,
    RecyclerView.State state,
    RecyclerView.LayoutManager.LayoutPrefetchRegistry layoutPrefetchRegistry
)

Gather all positions from the LayoutManager to be prefetched, given specified momentum.

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.

int

Override this method if you want to support scroll bars.

int

Override this method if you want to support scroll bars.

int

Override this method if you want to support scroll bars.

int

Override this method if you want to support scroll bars.

int

Override this method if you want to support scroll bars.

int

Override this method if you want to support scroll bars.

void

Temporarily detach and scrap all currently attached child views.

void
detachAndScrapView(
    @NonNull View child,
    @NonNull RecyclerView.Recycler recycler
)

Detach a child view and add it to a Recycler's scrap heap.

void

Detach a child view and add it to a Recycler's scrap heap.

void

Temporarily detach a child view.

void
detachViewAt(int index)

Temporarily detach a child view.

void

Ends all animations on the view created by the ItemAnimator.

@Nullable View

Traverses the ancestors of the given view and returns the item view that contains it and also a direct child of the LayoutManager.

int

Returns offset of the RecyclerView's text baseline from the its top boundary.

int

Returns the total height of item decorations applied to child's bottom.

@Nullable View
getChildAt(int index)

Return the child view at the given index

int

Return the current number of child views attached to the parent RecyclerView.

static int
getChildMeasureSpec(
    int parentSize,
    int padding,
    int childDimension,
    boolean canScroll
)

This method is deprecated.

use getChildMeasureSpec

static int
getChildMeasureSpec(
    int parentSize,
    int parentMode,
    int padding,
    int childDimension,
    boolean canScroll
)

Calculate a MeasureSpec value for measuring a child view in one dimension.

boolean

Check if the RecyclerView is configured to clip child views to its padding.

int

Returns the bottom edge of the given child view within its parent, offset by any applied ItemDecorations.

void

Returns the bounds of the view including its decoration and margins.

int

Returns the left edge of the given child view within its parent, offset by any applied ItemDecorations.

int

Returns the measured height of the given child, plus the additional size of any insets applied by ItemDecorations.

int

Returns the measured width of the given child, plus the additional size of any insets applied by ItemDecorations.

int

Returns the right edge of the given child view within its parent, offset by any applied ItemDecorations.

int

Returns the top edge of the given child view within its parent, offset by any applied ItemDecorations.

@Nullable View

Returns the item View which has or contains focus.

@Px int

Returns the height that is currently relevant to the LayoutManager.

int

Return the height measurement spec mode that is currently relevant to the LayoutManager.

int

Returns the number of items in the adapter bound to the parent RecyclerView.

int

Returns the View type defined by the adapter.

int

Returns the resolved layout direction for this RecyclerView.

int

Returns the total width of item decorations applied to child's left.

@Px int
@Px int
@Px int

Return the bottom padding of the parent RecyclerView

@Px int

Return the end padding of the parent RecyclerView

@Px int

Return the left padding of the parent RecyclerView

@Px int

Return the right padding of the parent RecyclerView

@Px int

Return the start padding of the parent RecyclerView

@Px int

Return the top padding of the parent RecyclerView

int

Returns the adapter position of the item represented by the given View.

static RecyclerView.LayoutManager.Properties
getProperties(
    @NonNull Context context,
    @Nullable AttributeSet attrs,
    int defStyleAttr,
    int defStyleRes
)

Parse the xml attributes to get the most common properties used by layout managers.

int

Returns the total width of item decorations applied to child's right.

int

Returns the selection mode for accessibility.

int

Returns the total height of item decorations applied to child's top.

void
getTransformedBoundingBox(
    @NonNull View child,
    boolean includeDecorInsets,
    @NonNull Rect out
)

Calculates the bounding box of the View while taking into account its matrix changes (translation, scale etc) with respect to the RecyclerView.

@Px int

Returns the width that is currently relevant to the LayoutManager.

int

Return the width measurement spec mode that is currently relevant to the LayoutManager.

boolean

Returns true if the RecyclerView this LayoutManager is bound to has or contains focus.

void

Flags a view so that it will not be scrapped or recycled.

boolean

Returns whether LayoutManager is currently attached to a RecyclerView which is attached to a window.

boolean

Returns true if the RecyclerView this LayoutManager is bound to has focus.

final boolean

Sets whether the LayoutManager should be queried for views outside of its viewport while the UI thread is idle between frames.

boolean

Returns whether layout is hierarchical or not to be used for accessibility.

boolean

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
boolean
isViewPartiallyVisible(
    @NonNull View 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
layoutDecorated(
    @NonNull View child,
    int left,
    int top,
    int right,
    int bottom
)

Lay out the given child view within the RecyclerView using coordinates that include any current ItemDecorations.

void
layoutDecoratedWithMargins(
    @NonNull View child,
    int left,
    int top,
    int right,
    int bottom
)

Lay out the given child view within the RecyclerView using coordinates that include any current ItemDecorations and margins.

void
measureChild(@NonNull View 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
measureChildWithMargins(
    @NonNull View 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
moveView(int fromIndex, int toIndex)

Moves a View from one position to another.

void

Offset all child views attached to the parent RecyclerView by dx pixels along the horizontal axis.

void

Offset all child views attached to the parent RecyclerView by dy pixels along the vertical axis.

void

Called if the RecyclerView this LayoutManager is bound to has a different adapter set via setAdapter or swapAdapter.

boolean
onAddFocusables(
    @NonNull RecyclerView recyclerView,
    @NonNull ArrayList<View> views,
    int direction,
    int focusableMode
)

Called to populate focusable views within the RecyclerView.

void

Called when this LayoutManager is both attached to a RecyclerView and that RecyclerView is attached to a window.

void

This method is deprecated.

override onDetachedFromWindow

void

Called when this LayoutManager is detached from its parent RecyclerView or when its parent RecyclerView is detached from its window.

@Nullable View
onFocusSearchFailed(
    @NonNull View focused,
    int direction,
    @NonNull RecyclerView.Recycler recycler,
    @NonNull RecyclerView.State state
)

Called when searching for a focusable view in the given direction has failed for the current content of the RecyclerView.

void
void

Called by the accessibility delegate to initialize an accessibility event.

void

Called by the AccessibilityDelegate when the information about the current layout should be populated.

@Nullable View
onInterceptFocusSearch(@NonNull View focused, int direction)

This method gives a LayoutManager an opportunity to intercept the initial focus search before the default behavior of FocusFinder is used.

void
onItemsUpdated(
    @NonNull RecyclerView recyclerView,
    int positionStart,
    int itemCount
)

Called when items have been changed in the adapter.

void

Lay out all relevant child views from the given adapter.

void

Called after a full layout calculation is finished.

void
onMeasure(
    @NonNull RecyclerView.Recycler recycler,
    @NonNull RecyclerView.State state,
    int widthSpec,
    int heightSpec
)

Measure the attached RecyclerView.

boolean
onRequestChildFocus(
    @NonNull RecyclerView parent,
    @NonNull View child,
    @Nullable View focused
)

This method is deprecated.

Use onRequestChildFocus

boolean
onRequestChildFocus(
    @NonNull RecyclerView parent,
    @NonNull RecyclerView.State state,
    @NonNull View child,
    @Nullable View focused
)

Called when a descendant view of the RecyclerView requests focus.

void

RecyclerView calls this method to notify LayoutManager that scroll state has changed.

boolean
performAccessibilityAction(
    @NonNull RecyclerView.Recycler recycler,
    @NonNull RecyclerView.State state,
    int action,
    @Nullable Bundle args
)

Called by AccessibilityDelegate when an action is requested from the RecyclerView.

boolean
performAccessibilityActionForItem(
    @NonNull RecyclerView.Recycler recycler,
    @NonNull RecyclerView.State state,
    @NonNull View view,
    int action,
    @Nullable Bundle args
)

Called by AccessibilityDelegate when an accessibility action is requested on one of the children of LayoutManager.

void

Causes the Runnable to execute on the next animation time step.

void

Remove all views from the currently attached RecyclerView.

void

Removes all views and recycles them using the given recycler.

void
removeAndRecycleView(
    @NonNull View child,
    @NonNull RecyclerView.Recycler recycler
)

Remove a child view and recycle it using the given Recycler.

void
removeAndRecycleViewAt(
    int index,
    @NonNull RecyclerView.Recycler recycler
)

Remove a child view and recycle it using the given Recycler.

boolean

Removes the specified Runnable from the message queue.

void

Finish removing a view that was previously temporarily detached.

void

Remove a view from the currently attached RecyclerView if needed.

void
removeViewAt(int index)

Remove a view from the currently attached RecyclerView if needed.

boolean
requestChildRectangleOnScreen(
    @NonNull RecyclerView parent,
    @NonNull View child,
    @NonNull Rect rect,
    boolean immediate
)

Called when a child of the RecyclerView wants a particular rectangle to be positioned onto the screen.

boolean
requestChildRectangleOnScreen(
    @NonNull RecyclerView parent,
    @NonNull View child,
    @NonNull Rect rect,
    boolean immediate,
    boolean focusedChildVisible
)

Requests that the given child of the RecyclerView be positioned onto the screen.

void

Calls RecyclerView#requestLayout on the underlying RecyclerView

void

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.

int
scrollHorizontallyBy(
    int dx,
    RecyclerView.Recycler recycler,
    RecyclerView.State state
)

Scroll horizontally by dx pixels in screen coordinates and return the distance traveled.

int
scrollVerticallyBy(
    int dy,
    RecyclerView.Recycler recycler,
    RecyclerView.State state
)

Scroll vertically by dy pixels in screen coordinates and return the distance traveled.

void
setAutoMeasureEnabled(boolean enabled)

This method is deprecated.

Implementors of LayoutManager should define whether or not it uses AutoMeasure by overriding isAutoMeasureEnabled.

final void
setItemPrefetchEnabled(boolean enabled)

Sets whether the LayoutManager should be queried for views outside of its viewport while the UI thread is idle between frames.

void
setMeasuredDimension(int widthSize, int heightSize)

Set the measured dimensions of the host RecyclerView.

void
setMeasurementCacheEnabled(boolean measurementCacheEnabled)

Sets whether RecyclerView should use its own measurement cache for the children.

void
smoothScrollToPosition(
    RecyclerView recyclerView,
    RecyclerView.State state,
    int position
)

Smooth scroll to the specified adapter position.

void

Starts a smooth scroll using the provided SmoothScroller.

void

View can be scrapped and recycled again.

Constants

DEFAULT_SPAN_COUNT

Added in 1.0.0
public static final int DEFAULT_SPAN_COUNT = -1

Public constructors

GridLayoutManager

Added in 1.0.0
public GridLayoutManager(Context context, int spanCount)

Creates a vertical GridLayoutManager

Parameters
Context context

Current context, will be used to access resources.

int spanCount

The number of columns in the grid

GridLayoutManager

Added in 1.0.0
public GridLayoutManager(
    Context context,
    AttributeSet attrs,
    int defStyleAttr,
    int defStyleRes
)

Constructor used when layout manager is set in XML by RecyclerView attribute "layoutManager". If spanCount is not specified in the XML, it defaults to a single column. spanCount

GridLayoutManager

Added in 1.0.0
public GridLayoutManager(
    Context context,
    int spanCount,
    int orientation,
    boolean reverseLayout
)
Parameters
Context context

Current context, will be used to access resources.

int spanCount

The number of columns or rows in the grid

int orientation

Layout orientation. Should be HORIZONTAL or VERTICAL.

boolean reverseLayout

When set to true, layouts from end to start.

Public methods

checkLayoutParams

public boolean checkLayoutParams(RecyclerView.LayoutParams lp)

Determines the validity of the supplied LayoutParams object.

This should check to make sure that the object is of the correct type and all values are within acceptable ranges. The default implementation returns true for non-null params.

Parameters
RecyclerView.LayoutParams lp

LayoutParams object to check

Returns
boolean

true if this LayoutParams object is valid, false otherwise

computeHorizontalScrollOffset

public int computeHorizontalScrollOffset(RecyclerView.State state)

Override this method if you want to support scroll bars.

Read computeHorizontalScrollOffset for details.

Default implementation returns 0.

Parameters
RecyclerView.State state

Current State of RecyclerView where you can find total item count

Returns
int

The horizontal offset of the scrollbar's thumb

computeHorizontalScrollRange

public int computeHorizontalScrollRange(RecyclerView.State state)

Override this method if you want to support scroll bars.

Read computeHorizontalScrollRange for details.

Default implementation returns 0.

Parameters
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

computeVerticalScrollOffset

public int computeVerticalScrollOffset(RecyclerView.State state)

Override this method if you want to support scroll bars.

Read computeVerticalScrollOffset for details.

Default implementation returns 0.

Parameters
RecyclerView.State state

Current State of RecyclerView where you can find total item count

Returns
int

The vertical offset of the scrollbar's thumb

computeVerticalScrollRange

public int computeVerticalScrollRange(RecyclerView.State state)

Override this method if you want to support scroll bars.

Read computeVerticalScrollRange for details.

Default implementation returns 0.

Parameters
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

generateDefaultLayoutParams

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).

generateLayoutParams

public RecyclerView.LayoutParams generateLayoutParams(ViewGroup.LayoutParams lp)

Create a LayoutParams object suitable for this LayoutManager, copying relevant values from the supplied LayoutParams object if possible.

Important: if you use your own custom LayoutParams type you must also override checkLayoutParams, generateLayoutParams and generateLayoutParams.

Parameters
ViewGroup.LayoutParams lp

Source LayoutParams object to copy values from

Returns
RecyclerView.LayoutParams

a new LayoutParams object

generateLayoutParams

public RecyclerView.LayoutParams generateLayoutParams(Context c, AttributeSet attrs)

Create a LayoutParams object suitable for this LayoutManager from an inflated layout resource.

Important: if you use your own custom LayoutParams type you must also override checkLayoutParams, generateLayoutParams and generateLayoutParams.

Parameters
Context c

Context for obtaining styled attributes

AttributeSet attrs

AttributeSet describing the supplied arguments

Returns
RecyclerView.LayoutParams

a new LayoutParams object

getColumnCountForAccessibility

public int getColumnCountForAccessibility(
    RecyclerView.Recycler recycler,
    RecyclerView.State state
)

Returns the number of columns for accessibility.

Default implementation returns the number of items in the adapter if LayoutManager supports horizontal scrolling or 1 if LayoutManager does not support horizontal scrolling.

Parameters
RecyclerView.Recycler recycler

The Recycler that can be used to convert view positions into adapter positions

RecyclerView.State state

The current state of RecyclerView

Returns
int

The number of rows in LayoutManager for accessibility.

getRowCountForAccessibility

public int getRowCountForAccessibility(
    RecyclerView.Recycler recycler,
    RecyclerView.State state
)

Returns the number of rows for accessibility.

Default implementation returns the number of items in the adapter if LayoutManager supports vertical scrolling or 1 if LayoutManager does not support vertical scrolling.

Parameters
RecyclerView.Recycler recycler

The Recycler that can be used to convert view positions into adapter positions

RecyclerView.State state

The current state of RecyclerView

Returns
int

The number of rows in LayoutManager for accessibility.

getSpanCount

Added in 1.0.0
public int getSpanCount()

Returns the number of spans laid out by this grid.

Returns
int

The number of spans

See also
setSpanCount

getSpanSizeLookup

Added in 1.0.0
public GridLayoutManager.SpanSizeLookup getSpanSizeLookup()

Returns the current SpanSizeLookup used by the GridLayoutManager.

Returns
GridLayoutManager.SpanSizeLookup

The current SpanSizeLookup used by the GridLayoutManager.

isUsingSpansToEstimateScrollbarDimensions

Added in 1.1.0
public boolean isUsingSpansToEstimateScrollbarDimensions()

Returns true if the scroll offset and scroll range calculations take account of span information. See setUsingSpansToEstimateScrollbarDimensions for more information on this topic. Defaults to false.

Returns
boolean

true if the scroll offset and scroll range calculations take account of span information.

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
View focused

The currently focused view

int direction

One of FOCUS_UP, FOCUS_DOWN, FOCUS_LEFT, FOCUS_RIGHT, FOCUS_BACKWARD, FOCUS_FORWARD or 0 for not applicable

RecyclerView.Recycler recycler

The recycler to use for obtaining views for currently offscreen items

RecyclerView.State state

Transient state of RecyclerView

Returns
View

The chosen view to be focused if a focusable view is found, otherwise an unfocusable view to become visible onto the screen, else null.

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 .

You should override getRowCountForAccessibility, getColumnCountForAccessibility, isLayoutHierarchical and getSelectionModeForAccessibility for more accurate accessibility information.

Parameters
@NonNull RecyclerView.Recycler recycler

The Recycler that can be used to convert view positions into adapter positions

@NonNull RecyclerView.State state

The current state of RecyclerView

@NonNull AccessibilityNodeInfoCompat info

The info that should be filled by the LayoutManager

onInitializeAccessibilityNodeInfoForItem

public void onInitializeAccessibilityNodeInfoForItem(
    RecyclerView.Recycler recycler,
    RecyclerView.State state,
    View host,
    AccessibilityNodeInfoCompat info
)

Called by the AccessibilityDelegate when the accessibility information for a specific item should be populated.

Default implementation adds basic positioning information about the item.

Parameters
RecyclerView.Recycler recycler

The Recycler that can be used to convert view positions into adapter positions

RecyclerView.State state

The current state of RecyclerView

View host

The child for which accessibility node info should be populated

AccessibilityNodeInfoCompat info

The info to fill out about the item

onItemsAdded

public void onItemsAdded(
    RecyclerView recyclerView,
    int positionStart,
    int itemCount
)

Called when items have been added to the adapter. The LayoutManager may choose to requestLayout if the inserted items would require refreshing the currently visible set of child views. (e.g. currently empty space would be filled by appended items, etc.)

onItemsChanged

public void onItemsChanged(RecyclerView recyclerView)

Called in response to a call to notifyDataSetChanged or swapAdapter ()} and signals that the the entire data set has changed.

onItemsMoved

public void onItemsMoved(RecyclerView recyclerView, int from, int to, int itemCount)

Called when an item is moved withing the adapter.

Note that, an item may also change position in response to another ADD/REMOVE/MOVE operation. This callback is only called if and only if notifyItemMoved is called.

onItemsRemoved

public void onItemsRemoved(
    RecyclerView recyclerView,
    int positionStart,
    int itemCount
)

Called when items have been removed from the adapter.

onItemsUpdated

public void onItemsUpdated(
    RecyclerView recyclerView,
    int positionStart,
    int itemCount,
    Object payload
)

Called when items have been changed in the adapter and with optional payload. Default implementation calls onItemsUpdated.

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 onLayoutChildren calls due to animations or layout measurement but it will include only one onLayoutCompleted call. This method will be called at the end of layout call.

This is a good place for the LayoutManager to do some cleanup like pending scroll position, saved state etc.

Parameters
RecyclerView.State state

Transient state of RecyclerView

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.

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.

setMeasuredDimension

public void setMeasuredDimension(Rect 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 onMeasure. It is only called if a LayoutManager returns true from isAutoMeasureEnabled and it is called after the RecyclerView calls onLayoutChildren in the execution of onMeasure.

This method must call setMeasuredDimension.

The default implementation adds the RecyclerView's padding to the given bounding box then caps the value to be within the given measurement specs.

Parameters
Rect childrenBounds

The bounding box of all children

int wSpec

The widthMeasureSpec that was passed into the RecyclerView.

int hSpec

The heightMeasureSpec that was passed into the RecyclerView.

setSpanCount

Added in 1.0.0
public void setSpanCount(int spanCount)

Sets the number of spans to be laid out.

If getOrientation is VERTICAL, this is the number of columns. If getOrientation is HORIZONTAL, this is the number of rows.

Parameters
int spanCount

The total number of spans in the grid

See also
getSpanCount

setSpanSizeLookup

Added in 1.0.0
public void setSpanSizeLookup(GridLayoutManager.SpanSizeLookup spanSizeLookup)

Sets the source to get the number of spans occupied by each item in the adapter.

Parameters
GridLayoutManager.SpanSizeLookup spanSizeLookup

SpanSizeLookup instance to be used to query number of spans occupied by each item

setStackFromEnd

public void setStackFromEnd(boolean stackFromEnd)

stackFromEnd is not supported by GridLayoutManager. Consider using setReverseLayout.

setUsingSpansToEstimateScrollbarDimensions

Added in 1.1.0
public void setUsingSpansToEstimateScrollbarDimensions(
    boolean useSpansToEstimateScrollBarDimensions
)

When this flag is set, the scroll offset and scroll range calculations will take account of span information.

This is will increase the accuracy of the scroll bar's size and offset but will require more calls to getSpanGroupIndex".

This additional accuracy may or may not be needed, depending on the characteristics of your layout. You will likely benefit from this accuracy when:

  • The variation in item span sizes is large.
  • The size of your data set is small (if your data set is large, the scrollbar will likely be very small anyway, and thus the increased accuracy has less impact).
  • Calls to getSpanGroupIndex are fast.

If you decide to enable this feature, you should be sure that calls to getSpanGroupIndex are fast, that set span group index caching is set to true via a call to and span index caching is also enabled via a call to { }.

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 onLayoutChildren.

Whether item animations actually occur in a RecyclerView is actually determined by both the return value from this method and the 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.