StaggeredGridLayoutManager

Artifact: androidx.recyclerview:recyclerview

Added in 1.0.0

Kotlin |Java

public class StaggeredGridLayoutManager extends RecyclerView.LayoutManager implements RecyclerView.SmoothScroller.ScrollVectorProvider

java.lang.Object
↳	androidx.recyclerview.widget.RecyclerView.LayoutManager
	↳	androidx.recyclerview.widget.StaggeredGridLayoutManager

A LayoutManager that lays out children in a staggered grid formation. It supports horizontal &vertical layout as well as an ability to layout children in reverse.

Staggered grids are likely to have gaps at the edges of the layout. To avoid these gaps, StaggeredGridLayoutManager can offset spans independently or move items between spans. You can control this behavior via setGapStrategy.

Summary

Nested types
`public class StaggeredGridLayoutManager.LayoutParams extends RecyclerView.LayoutParams` LayoutParams used by StaggeredGridLayoutManager.

Constants
`static final int`	`GAP_HANDLING_LAZY = 1` This field is deprecated. No longer supported.
`static final int`	`GAP_HANDLING_MOVE_ITEMS_BETWEEN_SPANS = 2` When scroll state is changed to `SCROLL_STATE_IDLE`, StaggeredGrid will check if there are gaps in the because of full span items.
`static final int`	`GAP_HANDLING_NONE = 0` Does not do anything to hide gaps.
`static final int`	`HORIZONTAL = 0`
`static final int`	`VERTICAL = 1`

Public constructors
`StaggeredGridLayoutManager(int spanCount, int orientation)` Creates a StaggeredGridLayoutManager with given parameters.
`StaggeredGridLayoutManager( Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes )` Constructor used when layout manager is set in XML by RecyclerView attribute "layoutManager".

Public methods
`void`	`assertNotInLayoutOrScroll(String message)` Checks if RecyclerView is in the middle of a layout or scroll and throws an `IllegalStateException` if it is.
`boolean`	`canScrollHorizontally()` Query if horizontal scrolling is currently supported.
`boolean`	`canScrollVertically()` Query if vertical scrolling is currently supported.
`boolean`	`checkLayoutParams(RecyclerView.LayoutParams lp)` Determines the validity of the supplied LayoutParams object.
`int`	`computeHorizontalScrollExtent(RecyclerView.State state)` Override this method if you want to support scroll bars.
`int`	`computeHorizontalScrollOffset(RecyclerView.State state)` Override this method if you want to support scroll bars.
`int`	`computeHorizontalScrollRange(RecyclerView.State state)` 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`	`computeVerticalScrollExtent(RecyclerView.State state)` Override this method if you want to support scroll bars.
`int`	`computeVerticalScrollOffset(RecyclerView.State state)` Override this method if you want to support scroll bars.
`int`	`computeVerticalScrollRange(RecyclerView.State state)` Override this method if you want to support scroll bars.
`int[]`	`findFirstCompletelyVisibleItemPositions(int[] into)` Returns the adapter position of the first completely visible view for each span.
`int[]`	`findFirstVisibleItemPositions(int[] into)` Returns the adapter position of the first visible view for each span.
`int[]`	`findLastCompletelyVisibleItemPositions(int[] into)` Returns the adapter position of the last completely visible view for each span.
`int[]`	`findLastVisibleItemPositions(int[] into)` Returns the adapter position of the last visible view for each span.
`RecyclerView.LayoutParams`	`generateDefaultLayoutParams()` Create a default `LayoutParams` object for a child of the RecyclerView.
`RecyclerView.LayoutParams`	`generateLayoutParams(ViewGroup.LayoutParams lp)` Create a LayoutParams object suitable for this LayoutManager, copying relevant values from the supplied LayoutParams object if possible.
`RecyclerView.LayoutParams`	`generateLayoutParams(Context c, AttributeSet attrs)` Create a LayoutParams object suitable for this LayoutManager from an inflated layout resource.
`int`	`getColumnCountForAccessibility( @NonNull RecyclerView.Recycler recycler, @NonNull RecyclerView.State state )` Returns the number of columns for accessibility.
`int`	`getGapStrategy()` Returns the current gap handling strategy for StaggeredGridLayoutManager.
`int`	`getOrientation()`
`boolean`	`getReverseLayout()` Returns whether views are laid out in reverse order or not.
`int`	`getRowCountForAccessibility( @NonNull RecyclerView.Recycler recycler, @NonNull RecyclerView.State state )` Returns the number of rows for accessibility.
`int`	`getSpanCount()` Returns the number of spans laid out by StaggeredGridLayoutManager.
`void`	`invalidateSpanAssignments()` For consistency, StaggeredGridLayoutManager keeps a mapping between spans and items.
`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 `onMeasure`.
`boolean`	`isLayoutReversed()` Query if the layout is in reverse order.
`void`	`offsetChildrenHorizontal(int dx)` Offset all child views attached to the parent RecyclerView by dx pixels along the horizontal axis.
`void`	`offsetChildrenVertical(int dy)` Offset all child views attached to the parent RecyclerView by dy pixels along the vertical axis.
`void`	`onAdapterChanged( @Nullable RecyclerView.Adapter oldAdapter, @Nullable RecyclerView.Adapter newAdapter )` Called if the RecyclerView this LayoutManager is bound to has a different adapter set via `setAdapter` or `swapAdapter`.
`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.
`@Nullable 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`	`onInitializeAccessibilityEvent(AccessibilityEvent event)`
`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.
`void`	`onInitializeAccessibilityNodeInfoForItem( @NonNull RecyclerView.Recycler recycler, @NonNull RecyclerView.State state, @NonNull View host, @NonNull AccessibilityNodeInfoCompat info )` 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`	`onItemsChanged(RecyclerView recyclerView)` 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`	`onLayoutChildren( RecyclerView.Recycler recycler, RecyclerView.State state )` Lay out all relevant child views from the given adapter.
`void`	`onLayoutCompleted(RecyclerView.State state)` Called after a full layout calculation is finished.
`void`	`onRestoreInstanceState(Parcelable state)` Called when the RecyclerView is ready to restore the state based on a previous RecyclerView.
`Parcelable`	`onSaveInstanceState()` Called when the LayoutManager should save its state.
`void`	`onScrollStateChanged(int state)` RecyclerView calls this method to notify LayoutManager that scroll state has changed.
`int`	`scrollHorizontallyBy( int dx, RecyclerView.Recycler recycler, RecyclerView.State state )` Scroll horizontally by dx pixels in screen coordinates and return the distance traveled.
`void`	`scrollToPosition(int position)` Scroll to the specified adapter position.
`void`	`scrollToPositionWithOffset(int position, int offset)` Scroll to the specified adapter position with the given offset from layout start.
`int`	`scrollVerticallyBy( int dy, RecyclerView.Recycler recycler, RecyclerView.State state )` Scroll vertically by dy pixels in screen coordinates and return the distance traveled.
`void`	`setGapStrategy(int gapStrategy)` Sets the gap handling strategy for StaggeredGridLayoutManager.
`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`	`setOrientation(int orientation)` Sets the orientation of the layout.
`void`	`setReverseLayout(boolean reverseLayout)` Sets whether LayoutManager should start laying out items from the end of the UI.
`void`	`setSpanCount(int spanCount)` Sets the number of spans for the layout.
`void`	`smoothScrollToPosition( RecyclerView recyclerView, RecyclerView.State state, int position )` Smooth scroll to the specified adapter position.
`boolean`	`supportsPredictiveItemAnimations()` Returns whether this LayoutManager supports "predictive item animations".

Inherited methods

From androidx.recyclerview.widget.RecyclerView.LayoutManager

`void`	`addDisappearingView(View child)` 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`	`assertInLayoutOrScroll(String message)` Checks if RecyclerView is in the middle of a layout or scroll and throws an `IllegalStateException` if it is not.
`void`	`attachView(@NonNull View child)` 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`	`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.
`void`	`detachAndScrapAttachedViews(@NonNull RecyclerView.Recycler recycler)` 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`	`detachAndScrapViewAt(int index, @NonNull RecyclerView.Recycler recycler)` Detach a child view and add it to a `Recycler's` scrap heap.
`void`	`detachView(@NonNull View child)` Temporarily detach a child view.
`void`	`detachViewAt(int index)` Temporarily detach a child view.
`void`	`endAnimation(View view)` Ends all animations on the view created by the `ItemAnimator`.
`@Nullable 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.
`@Nullable View`	`findViewByPosition(int position)` Finds the view which represents the given adapter position.
`int`	`getBaseline()` Returns offset of the RecyclerView's text baseline from the its top boundary.
`int`	`getBottomDecorationHeight(@NonNull View child)` 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`	`getChildCount()` 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`	`getClipToPadding()` Check if the RecyclerView is configured to clip child views to its padding.
`int`	`getDecoratedBottom(@NonNull View child)` Returns the bottom edge of the given child view within its parent, offset by any applied `ItemDecorations`.
`void`	`getDecoratedBoundsWithMargins(@NonNull View view, @NonNull Rect outBounds)` Returns the bounds of the view including its decoration and margins.
`int`	`getDecoratedLeft(@NonNull View child)` Returns the left edge of the given child view within its parent, offset by any applied `ItemDecorations`.
`int`	`getDecoratedMeasuredHeight(@NonNull View child)` Returns the measured height of the given child, plus the additional size of any insets applied by `ItemDecorations`.
`int`	`getDecoratedMeasuredWidth(@NonNull View child)` Returns the measured width of the given child, plus the additional size of any insets applied by `ItemDecorations`.
`int`	`getDecoratedRight(@NonNull View child)` Returns the right edge of the given child view within its parent, offset by any applied `ItemDecorations`.
`int`	`getDecoratedTop(@NonNull View child)` Returns the top edge of the given child view within its parent, offset by any applied `ItemDecorations`.
`@Nullable View`	`getFocusedChild()` Returns the item View which has or contains focus.
`@Px int`	`getHeight()` Returns the height that is currently relevant to the LayoutManager.
`int`	`getHeightMode()` Return the height measurement spec mode that is currently relevant to the LayoutManager.
`int`	`getItemCount()` Returns the number of items in the adapter bound to the parent RecyclerView.
`int`	`getItemViewType(@NonNull View view)` Returns the View type defined by the adapter.
`int`	`getLayoutDirection()` Returns the resolved layout direction for this RecyclerView.
`int`	`getLeftDecorationWidth(@NonNull View child)` Returns the total width of item decorations applied to child's left.
`@Px int`	`getMinimumHeight()`
`@Px int`	`getMinimumWidth()`
`@Px int`	`getPaddingBottom()` Return the bottom padding of the parent RecyclerView
`@Px int`	`getPaddingEnd()` Return the end padding of the parent RecyclerView
`@Px int`	`getPaddingLeft()` Return the left padding of the parent RecyclerView
`@Px int`	`getPaddingRight()` Return the right padding of the parent RecyclerView
`@Px int`	`getPaddingStart()` Return the start padding of the parent RecyclerView
`@Px int`	`getPaddingTop()` Return the top padding of the parent RecyclerView
`int`	`getPosition(@NonNull View view)` 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`	`getRightDecorationWidth(@NonNull View child)` Returns the total width of item decorations applied to child's right.
`int`	`getSelectionModeForAccessibility( @NonNull RecyclerView.Recycler recycler, @NonNull RecyclerView.State state )` Returns the selection mode for accessibility.
`int`	`getTopDecorationHeight(@NonNull View child)` 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`	`getWidth()` Returns the width that is currently relevant to the LayoutManager.
`int`	`getWidthMode()` Return the width measurement spec mode that is currently relevant to the LayoutManager.
`boolean`	`hasFocus()` Returns true if the RecyclerView this LayoutManager is bound to has or contains focus.
`void`	`ignoreView(@NonNull View view)` Flags a view so that it will not be scrapped or recycled.
`boolean`	`isAttachedToWindow()` Returns whether LayoutManager is currently attached to a RecyclerView which is attached to a window.
`boolean`	`isFocused()` Returns true if the RecyclerView this LayoutManager is bound to has focus.
`final boolean`	`isItemPrefetchEnabled()` Sets whether the LayoutManager should be queried for views outside of its viewport while the UI thread is idle between frames.
`boolean`	`isLayoutHierarchical( @NonNull RecyclerView.Recycler recycler, @NonNull RecyclerView.State state )` Returns whether layout is hierarchical or not to be used for accessibility.
`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.
`boolean`	`isSmoothScrolling()`
`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.
`boolean`	`onAddFocusables( @NonNull RecyclerView recyclerView, @NonNull ArrayList<View> views, int direction, int focusableMode )` Called to populate focusable views within the RecyclerView.
`void`	`@CallSuper onAttachedToWindow(RecyclerView view)` Called when this LayoutManager is both attached to a RecyclerView and that RecyclerView is attached to a window.
`void`	`onDetachedFromWindow(RecyclerView view)` This method is deprecated. override `onDetachedFromWindow`
`void`	`onInitializeAccessibilityEvent( @NonNull RecyclerView.Recycler recycler, @NonNull RecyclerView.State state, @NonNull AccessibilityEvent event )` Called by the accessibility delegate to initialize an accessibility event.
`@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`	`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.
`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`	`postOnAnimation(Runnable action)` Causes the Runnable to execute on the next animation time step.
`void`	`removeAllViews()` Remove all views from the currently attached RecyclerView.
`void`	`removeAndRecycleAllViews(@NonNull RecyclerView.Recycler recycler)` 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`	`removeCallbacks(Runnable action)` Removes the specified Runnable from the message queue.
`void`	`removeDetachedView(@NonNull View child)` Finish removing a view that was previously temporarily `detached`.
`void`	`removeView(View child)` 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`	`requestLayout()` Calls `RecyclerView#requestLayout` on the underlying RecyclerView
`void`	`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(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`	`startSmoothScroll(RecyclerView.SmoothScroller smoothScroller)` Starts a smooth scroll using the provided `SmoothScroller`.
`void`	`stopIgnoringView(@NonNull View view)` View can be scrapped and recycled again.

Constants

GAP_HANDLING_LAZY

Added in 1.0.0

Deprecated in 1.0.0

public static final int GAP_HANDLING_LAZY = 1

GAP_HANDLING_MOVE_ITEMS_BETWEEN_SPANS

Added in 1.0.0

public static final int GAP_HANDLING_MOVE_ITEMS_BETWEEN_SPANS = 2

When scroll state is changed to SCROLL_STATE_IDLE, StaggeredGrid will check if there are gaps in the because of full span items. If it finds, it will re-layout and move items to correct positions with animations.

For example, if LayoutManager ends up with the following layout due to adapter changes:

AAA
_BC
DDD

It will animate to the following state:

AAA
BC_
DDD

GAP_HANDLING_NONE

Added in 1.0.0

public static final int GAP_HANDLING_NONE = 0

Does not do anything to hide gaps.

HORIZONTAL

Added in 1.0.0

public static final int HORIZONTAL = 0

VERTICAL

Added in 1.0.0

public static final int VERTICAL = 1

Public constructors

StaggeredGridLayoutManager

Added in 1.0.0

public StaggeredGridLayoutManager(int spanCount, int orientation)

Creates a StaggeredGridLayoutManager with given parameters.

Parameters
`int spanCount`	If orientation is vertical, spanCount is number of columns. If orientation is horizontal, spanCount is number of rows.
`int orientation`	`VERTICAL` or `HORIZONTAL`

StaggeredGridLayoutManager

Added in 1.0.0

public StaggeredGridLayoutManager(
    Context context,
    AttributeSet attrs,
    int defStyleAttr,
    int defStyleRes
)

Constructor used when layout manager is set in XML by RecyclerView attribute "layoutManager". Defaults to single column and vertical.

Public methods

assertNotInLayoutOrScroll

public void assertNotInLayoutOrScroll(String message)

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

Parameters
`String message`	The message for the exception. Can be null.

See also
`assertInLayoutOrScroll`

canScrollHorizontally

public boolean canScrollHorizontally()

Query if horizontal scrolling is currently supported. The default implementation returns false.

Returns
`boolean`	True if this LayoutManager can scroll the current contents horizontally

canScrollVertically

public boolean canScrollVertically()

Query if vertical scrolling is currently supported. The default implementation returns false.

Returns
`boolean`	True if this LayoutManager can scroll the current contents vertically

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

public int computeHorizontalScrollExtent(RecyclerView.State state)

Override this method if you want to support scroll bars.

Read computeHorizontalScrollExtent for details.

Default implementation returns 0.

Parameters
`RecyclerView.State state`	Current state of RecyclerView

Returns
`int`	The horizontal extent of the scrollbar's thumb

See also
`computeHorizontalScrollExtent`

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

See also
`computeHorizontalScrollOffset`

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

See also
`computeHorizontalScrollRange`

computeScrollVectorForPosition

Added in 1.4.0-rc01

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 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 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
`PointF`	the scroll vector for a given position.

public int computeVerticalScrollExtent(RecyclerView.State state)

Override this method if you want to support scroll bars.

Read computeVerticalScrollExtent for details.

Default implementation returns 0.

Parameters
`RecyclerView.State state`	Current state of RecyclerView

Returns
`int`	The vertical extent of the scrollbar's thumb

See also
`computeVerticalScrollExtent`

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

See also
`computeVerticalScrollOffset`

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

See also
`computeVerticalScrollRange`

findFirstCompletelyVisibleItemPositions

Added in 1.0.0

public int[] findFirstCompletelyVisibleItemPositions(int[] into)

Returns the adapter position of the first completely visible view for each span.

Note that, this value is not affected by layout orientation or item order traversal. (setReverseLayout). 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.

StaggeredGridLayoutManager may pre-cache some views that are not necessarily visible. Those views are ignored in this method.

Parameters
`int[] into`	An array to put the results into. If you don't provide any, LayoutManager will create a new one.

Returns
`int[]`	The adapter position of the first fully visible item in each span. If a span does not have any items, `NO_POSITION` is returned for that span.

See also
`findFirstVisibleItemPositions`
`findLastCompletelyVisibleItemPositions`

findFirstVisibleItemPositions

Added in 1.0.0

public int[] findFirstVisibleItemPositions(int[] into)

Returns the adapter position of the first visible view for each span.

Note that, this value is not affected by layout orientation or item order traversal. (setReverseLayout). 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.

StaggeredGridLayoutManager may pre-cache some views that are not necessarily visible. Those views are ignored in this method.

Parameters
`int[] into`	An array to put the results into. If you don't provide any, LayoutManager will create a new one.

Returns
`int[]`	The adapter position of the first visible item in each span. If a span does not have any items, `NO_POSITION` is returned for that span.

See also
`findFirstCompletelyVisibleItemPositions`
`findLastVisibleItemPositions`

findLastCompletelyVisibleItemPositions

Added in 1.0.0

public int[] findLastCompletelyVisibleItemPositions(int[] into)

Returns the adapter position of the last completely visible view for each span.

Note that, this value is not affected by layout orientation or item order traversal. (setReverseLayout). 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.

StaggeredGridLayoutManager may pre-cache some views that are not necessarily visible. Those views are ignored in this method.

Parameters
`int[] into`	An array to put the results into. If you don't provide any, LayoutManager will create a new one.

Returns
`int[]`	The adapter position of the last fully visible item in each span. If a span does not have any items, `NO_POSITION` is returned for that span.

See also
`findFirstCompletelyVisibleItemPositions`
`findLastVisibleItemPositions`

findLastVisibleItemPositions

Added in 1.0.0

public int[] findLastVisibleItemPositions(int[] into)

Returns the adapter position of the last visible view for each span.

Note that, this value is not affected by layout orientation or item order traversal. (setReverseLayout). 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.

StaggeredGridLayoutManager may pre-cache some views that are not necessarily visible. Those views are ignored in this method.

Parameters
`int[] into`	An array to put the results into. If you don't provide any, LayoutManager will create a new one.

Returns
`int[]`	The adapter position of the last visible item in each span. If a span does not have any items, `NO_POSITION` is returned for that span.

See also
`findLastCompletelyVisibleItemPositions`
`findFirstVisibleItemPositions`

generateDefaultLayoutParams

Added in 1.4.0-rc01

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 RecyclerView.LayoutParams for this purpose.

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

Returns
`RecyclerView.LayoutParams`	A new LayoutParams for a child view

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

public int getColumnCountForAccessibility(
    @NonNull RecyclerView.Recycler recycler,
    @NonNull 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
`@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

Returns
`int`	The number of rows in LayoutManager for accessibility.

getGapStrategy

Added in 1.0.0

public int getGapStrategy()

Returns the current gap handling strategy for StaggeredGridLayoutManager.

Staggered grid may have gaps in the layout due to changes in the adapter. To avoid gaps, StaggeredGridLayoutManager provides 2 options. Check GAP_HANDLING_NONE and GAP_HANDLING_MOVE_ITEMS_BETWEEN_SPANS for details.

By default, StaggeredGridLayoutManager uses GAP_HANDLING_MOVE_ITEMS_BETWEEN_SPANS.

Returns
`int`	Current gap handling strategy.

See also
`setGapStrategy`
`GAP_HANDLING_NONE`
`GAP_HANDLING_MOVE_ITEMS_BETWEEN_SPANS`

getOrientation

Added in 1.0.0

public int getOrientation()

getReverseLayout

Added in 1.0.0

public boolean getReverseLayout()

Returns whether views are laid out in reverse order or not.

Not that this value is not affected by RecyclerView's layout direction.

Returns
`boolean`	True if layout is reversed, false otherwise

See also
`setReverseLayout`

public int getRowCountForAccessibility(
    @NonNull RecyclerView.Recycler recycler,
    @NonNull 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
`@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

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 StaggeredGridLayoutManager.

Returns
`int`	Number of spans in the layout

invalidateSpanAssignments

Added in 1.0.0

public void invalidateSpanAssignments()

For consistency, StaggeredGridLayoutManager keeps a mapping between spans and items.

If you need to cancel current assignments, you can call this method which will clear all assignments and request a new layout.

isAutoMeasureEnabled

public 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 onMeasure.

This method returns false by default (it actually returns the value passed to the deprecated setAutoMeasureEnabled) 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, onMeasure 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 onLayoutChildren during a call to onMeasure, 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:

When onMeasure is called, if the provided measure specs both have a mode of EXACTLY, RecyclerView will set its measured dimensions accordingly and return, allowing layout to continue as normal (Actually, RecyclerView will call onMeasure for backwards compatibility reasons but it should not be overridden if AutoMeasure is being used).
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 onLayoutChildren with isPreLayout set to true. At this stage, getWidth and 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 onLayoutChildren with isMeasuring set to true and isPreLayout set to false. The LayoutManager can access the measurement specs via getHeight, getHeightMode, getWidth and getWidthMode.
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 setMeasuredDimension 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.
Any following calls to onMeasure will run onLayoutChildren with isMeasuring set to true and 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 onLayoutChildren call as if it is the last one.
When measure is complete and RecyclerView's onLayout 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 onLayoutChildren if the last measure spec was different from the final dimensions or adapter contents have changed between the measure call and the layout call.
Finally, animations are calculated and run as usual.

Returns
`boolean`	`True` if the measuring pass of layout should use the AutoMeasure mechanism of `RecyclerView` or `False` if it should be done by the LayoutManager's implementation of `onMeasure`.

See also
`setMeasuredDimension`
`onMeasure`

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.

offsetChildrenHorizontal

public void offsetChildrenHorizontal(int dx)

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

Parameters
`int dx`	Pixels to offset by

offsetChildrenVertical

public void offsetChildrenVertical(int dy)

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

Parameters
`int dy`	Pixels to offset by

public void onAdapterChanged(
    @Nullable RecyclerView.Adapter oldAdapter,
    @Nullable RecyclerView.Adapter newAdapter
)

Called if the RecyclerView this LayoutManager is bound to has a different adapter set via setAdapter or swapAdapter. The LayoutManager may use this opportunity to clear caches and configure state such that it can relayout appropriately with the new data and potentially new view types.

The default implementation removes all currently attached views.

Parameters
`@Nullable RecyclerView.Adapter oldAdapter`	The previous adapter instance. Will be null if there was previously no adapter.
`@Nullable RecyclerView.Adapter newAdapter`	The new adapter instance. Might be null if `setAdapter` is called with `null`.

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 onLayoutChildren 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 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
`RecyclerView view`	The RecyclerView this LayoutManager is bound to
`RecyclerView.Recycler recycler`	The recycler to use if you prefer to recycle your children instead of keeping them around.

See also
`onAttachedToWindow`

public @Nullable 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
`@Nullable 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.

onInitializeAccessibilityEvent

public void onInitializeAccessibilityEvent(AccessibilityEvent event)

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

See also
`onInitializeAccessibilityNodeInfo`
`getRowCountForAccessibility`
`getColumnCountForAccessibility`
`isLayoutHierarchical`
`getSelectionModeForAccessibility`

public void onInitializeAccessibilityNodeInfoForItem(
    @NonNull RecyclerView.Recycler recycler,
    @NonNull RecyclerView.State state,
    @NonNull View host,
    @NonNull 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
`@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 View host`	The child for which accessibility node info should be populated
`@NonNull AccessibilityNodeInfoCompat info`	The info to fill out about the item

See also
`onInitializeAccessibilityNodeInfoForItem`

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.)

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.

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.

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

Called when items have been removed from the adapter.

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.

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 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, the RecyclerView will have enough information to run those animations in a simple way. For example, the default ItemAnimator, DefaultItemAnimator, 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. Supporting predictive animations means that onLayoutChildren 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, 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.

Parameters
`RecyclerView.Recycler recycler`	Recycler to use for fetching potentially cached views for a position
`RecyclerView.State state`	Transient state of RecyclerView

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

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 getStateRestorationPolicy for more information.

Parameters
`Parcelable state`	The parcelable that was returned by the previous LayoutManager's `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
`Parcelable`	Necessary information for LayoutManager to be able to restore its state

onScrollStateChanged

public void onScrollStateChanged(int state)

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

Parameters
`int state`	The new scroll state for RecyclerView

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.

Parameters
`int dx`	distance to scroll by in pixels. X increases as scroll position approaches the right.
`RecyclerView.Recycler recycler`	Recycler to use for fetching potentially cached views for a position
`RecyclerView.State state`	Transient state of RecyclerView

Returns
`int`	The actual distance scrolled. The return value will be negative if dx was negative and scrolling proceeeded in that direction. `Math.abs(result)` may be less than dx if a boundary was reached.

scrollToPosition

public void scrollToPosition(int position)

Scroll to the specified adapter position. Actual position of the item on the screen depends on the LayoutManager implementation.

Parameters
`int position`	Scroll to this adapter position.

scrollToPositionWithOffset

Added in 1.0.0

public void scrollToPositionWithOffset(int position, int offset)

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

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 scrollToPosition.

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
`setReverseLayout`
`scrollToPosition`

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.

Parameters
`int dy`	distance to scroll in pixels. Y increases as scroll position approaches the bottom.
`RecyclerView.Recycler recycler`	Recycler to use for fetching potentially cached views for a position
`RecyclerView.State state`	Transient state of RecyclerView

Returns
`int`	The actual distance scrolled. The return value will be negative if dy was negative and scrolling proceeeded in that direction. `Math.abs(result)` may be less than dy if a boundary was reached.

setGapStrategy

Added in 1.0.0

public void setGapStrategy(int gapStrategy)

Sets the gap handling strategy for StaggeredGridLayoutManager. If the gapStrategy parameter is different than the current strategy, calling this method will trigger a layout request.

Parameters
`int gapStrategy`	The new gap handling strategy. Should be `GAP_HANDLING_MOVE_ITEMS_BETWEEN_SPANS` or `GAP_HANDLING_NONE`.

See also
`getGapStrategy`

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.

See also
`isAutoMeasureEnabled`
`setMeasuredDimension`

setOrientation

Added in 1.0.0

public void setOrientation(int orientation)

Sets the orientation of the layout. StaggeredGridLayoutManager will do its best to keep scroll position if this method is called after views are laid out.

Parameters
`int orientation`	`HORIZONTAL` or `VERTICAL`

setReverseLayout

Added in 1.0.0

public void setReverseLayout(boolean reverseLayout)

Sets whether LayoutManager should start laying out items from the end of the UI. The order items are traversed is not affected by this call.

For vertical layout, if it is set to true, first item will be at the bottom of the list.

For horizontal layouts, it depends on the layout direction. When set to true, If RecyclerView is LTR, than it will layout from RTL, if RecyclerView} is RTL, it will layout from LTR.

Parameters
`boolean reverseLayout`	Whether layout should be in reverse or not

setSpanCount

Added in 1.0.0

public void setSpanCount(int spanCount)

Sets the number of spans for the layout. This will invalidate all of the span assignments for Views.

Calling this method will automatically result in a new layout request unless the spanCount parameter is equal to current span count.

Parameters
`int spanCount`	Number of spans to layout

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 SmoothScroller instance and call startSmoothScroll.

Parameters
`RecyclerView recyclerView`	The RecyclerView to which this layout manager is attached
`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 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.

StaggeredGridLayoutManager

Summary

Nested types

Constants

Public constructors

Public methods

Inherited methods

Constants

GAP_HANDLING_LAZY

GAP_HANDLING_MOVE_ITEMS_BETWEEN_SPANS

GAP_HANDLING_NONE

HORIZONTAL

VERTICAL

Public constructors

StaggeredGridLayoutManager

StaggeredGridLayoutManager

Public methods

assertNotInLayoutOrScroll

canScrollHorizontally

canScrollVertically

checkLayoutParams

computeHorizontalScrollExtent

computeHorizontalScrollOffset

computeHorizontalScrollRange

computeScrollVectorForPosition

computeVerticalScrollExtent

computeVerticalScrollOffset

computeVerticalScrollRange

findFirstCompletelyVisibleItemPositions

findFirstVisibleItemPositions

findLastCompletelyVisibleItemPositions

findLastVisibleItemPositions

generateDefaultLayoutParams

generateLayoutParams

generateLayoutParams

getColumnCountForAccessibility

getGapStrategy

getOrientation

getReverseLayout

getRowCountForAccessibility

getSpanCount

invalidateSpanAssignments

isAutoMeasureEnabled

isLayoutReversed

offsetChildrenHorizontal

offsetChildrenVertical

onAdapterChanged

onDetachedFromWindow

onFocusSearchFailed

onInitializeAccessibilityEvent

onInitializeAccessibilityNodeInfo

onInitializeAccessibilityNodeInfoForItem

onItemsAdded

onItemsChanged

onItemsMoved

onItemsRemoved

onItemsUpdated

onLayoutChildren

onLayoutCompleted

onRestoreInstanceState

onSaveInstanceState

onScrollStateChanged

scrollHorizontallyBy

scrollToPosition

scrollToPositionWithOffset

scrollVerticallyBy

setGapStrategy

setMeasuredDimension

setOrientation

setReverseLayout

setSpanCount

smoothScrollToPosition

supportsPredictiveItemAnimations