GridLayoutManager

Artifact: androidx.leanback:leanback-grid

Kotlin |Java

class GridLayoutManager : RecyclerView.LayoutManager

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

A RecyclerView.LayoutManager implementation that lays out items in a grid for leanback VerticalGridView and HorizontalGridView.

Summary

Public constructors
`GridLayoutManager()`

Public functions
`Boolean`	`canScrollHorizontally()` Query if horizontal scrolling is currently supported.
`Boolean`	`canScrollVertically()` Query if vertical scrolling is currently supported.
`Boolean`	`checkLayoutParams(lp: RecyclerView.LayoutParams?)` Determines the validity of the supplied LayoutParams object.
`Unit`	`collectAdjacentPrefetchPositions( dx: Int, dy: Int, state: RecyclerView.State, layoutPrefetchRegistry: RecyclerView.LayoutManager.LayoutPrefetchRegistry )` Gather all positions from the LayoutManager to be prefetched, given specified momentum.
`Unit`	`collectInitialPrefetchPositions( adapterItemCount: Int, layoutPrefetchRegistry: RecyclerView.LayoutManager.LayoutPrefetchRegistry )` Gather all positions from the LayoutManager to be prefetched in preperation for its RecyclerView to come on screen, due to the movement of another, containing RecyclerView.
`RecyclerView.LayoutParams`	`generateDefaultLayoutParams()` Create a default `LayoutParams` object for a child of the RecyclerView.
`RecyclerView.LayoutParams`	`generateLayoutParams(lp: ViewGroup.LayoutParams)` Create a LayoutParams object suitable for this LayoutManager, copying relevant values from the supplied LayoutParams object if possible.
`RecyclerView.LayoutParams`	`generateLayoutParams(context: Context, attrs: AttributeSet)` Create a LayoutParams object suitable for this LayoutManager from an inflated layout resource.
`Int`	`getColumnCountForAccessibility( recycler: RecyclerView.Recycler, state: RecyclerView.State )` Returns the number of columns for accessibility.
`Int`	`getDecoratedBottom(child: View)` Returns the bottom edge of the given child view within its parent, offset by any applied `ItemDecorations`.
`Unit`	`getDecoratedBoundsWithMargins(view: View, outBounds: Rect)` Returns the bounds of the view including its decoration and margins.
`Int`	`getDecoratedLeft(child: View)` Returns the left edge of the given child view within its parent, offset by any applied `ItemDecorations`.
`Int`	`getDecoratedRight(child: View)` Returns the right edge of the given child view within its parent, offset by any applied `ItemDecorations`.
`Int`	`getDecoratedTop(child: View)` Returns the top edge of the given child view within its parent, offset by any applied `ItemDecorations`.
`Int`	`getRowCountForAccessibility( recycler: RecyclerView.Recycler, state: RecyclerView.State )` Returns the number of rows for accessibility.
`Unit`	`onAdapterChanged( oldAdapter: RecyclerView.Adapter?, newAdapter: RecyclerView.Adapter? )` Called if the RecyclerView this LayoutManager is bound to has a different adapter set via `setAdapter` or `swapAdapter`.
`Boolean`	`onAddFocusables( recyclerView: RecyclerView, views: ArrayList<View!>, direction: Int, focusableMode: Int )` Called to populate focusable views within the RecyclerView.
`Unit`	`onInitializeAccessibilityNodeInfo( recycler: RecyclerView.Recycler, state: RecyclerView.State, info: AccessibilityNodeInfoCompat )` Called by the AccessibilityDelegate when the information about the current layout should be populated.
`Unit`	`onInitializeAccessibilityNodeInfoForItem( recycler: RecyclerView.Recycler, state: RecyclerView.State, host: View, info: AccessibilityNodeInfoCompat )` Called by the AccessibilityDelegate when the accessibility information for a specific item should be populated.
`View?`	`onInterceptFocusSearch(focused: View?, direction: Int)` This method gives a LayoutManager an opportunity to intercept the initial focus search before the default behavior of `FocusFinder` is used.
`Unit`	`onItemsAdded( recyclerView: RecyclerView, positionStart: Int, itemCount: Int )` Called when items have been added to the adapter.
`Unit`	`onItemsChanged(recyclerView: RecyclerView)` Called in response to a call to `notifyDataSetChanged` or `swapAdapter` ()} and signals that the the entire data set has changed.
`Unit`	`onItemsMoved( recyclerView: RecyclerView, fromPosition: Int, toPosition: Int, itemCount: Int )` Called when an item is moved withing the adapter.
`Unit`	`onItemsRemoved( recyclerView: RecyclerView, positionStart: Int, itemCount: Int )` Called when items have been removed from the adapter.
`Unit`	`onItemsUpdated( recyclerView: RecyclerView, positionStart: Int, itemCount: Int )` Called when items have been changed in the adapter.
`Unit`	`onLayoutChildren( recycler: RecyclerView.Recycler, state: RecyclerView.State )` Lay out all relevant child views from the given adapter.
`Unit`	`onLayoutCompleted(state: RecyclerView.State)` Called after a full layout calculation is finished.
`Unit`	`onMeasure( recycler: RecyclerView.Recycler, state: RecyclerView.State, widthSpec: Int, heightSpec: Int )` Measure the attached RecyclerView.
`Boolean`	`onRequestChildFocus( parent: RecyclerView, state: RecyclerView.State, child: View, focused: View? )` Called when a descendant view of the RecyclerView requests focus.
`Unit`	`onRestoreInstanceState(state: Parcelable?)` 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.
`Boolean`	`performAccessibilityAction( recycler: RecyclerView.Recycler, state: RecyclerView.State, action: Int, args: Bundle? )` Called by AccessibilityDelegate when an action is requested from the RecyclerView.
`Unit`	`removeAndRecycleAllViews(recycler: RecyclerView.Recycler)` Removes all views and recycles them using the given recycler.
`Boolean`	`requestChildRectangleOnScreen( parent: RecyclerView, child: View, rect: Rect, immediate: Boolean )` Called when a child of the RecyclerView wants a particular rectangle to be positioned onto the screen.
`Int`	`scrollHorizontallyBy( dx: Int, recycler: RecyclerView.Recycler, state: RecyclerView.State )` Scroll horizontally by dx pixels in screen coordinates and return the distance traveled.
`Unit`	`scrollToPosition(position: Int)` Scroll to the specified adapter position.
`Int`	`scrollVerticallyBy( dy: Int, recycler: RecyclerView.Recycler, state: RecyclerView.State )` Scroll vertically by dy pixels in screen coordinates and return the distance traveled.
`Unit`	`setFocusOutAllowed(throughFront: Boolean, throughBack: Boolean)` Sets whether focus can move out from the front and/or back of the grid view.
`Unit`	`setOrientation(orientation: Int)` Sets grid view orientation.
`Unit`	`smoothScrollToPosition( recyclerView: RecyclerView, state: RecyclerView.State, position: Int )` Smooth scroll to the specified adapter position.
`Unit`	`startSmoothScroll(smoothScroller: RecyclerView.SmoothScroller)` Starts a smooth scroll using the provided `SmoothScroller`.
`Boolean`	`supportsPredictiveItemAnimations()` Returns whether this LayoutManager supports "predictive item animations".

Inherited functions

From androidx.recyclerview.widget.RecyclerView.LayoutManager

`Unit`	`addDisappearingView(child: View!)` 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.
`Unit`	`addDisappearingView(child: View!, index: Int)` 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.
`Unit`	`addView(child: View!)` Add a view to the currently attached RecyclerView if needed.
`Unit`	`addView(child: View!, index: Int)` Add a view to the currently attached RecyclerView if needed.
`Unit`	`assertInLayoutOrScroll(message: String!)` Checks if RecyclerView is in the middle of a layout or scroll and throws an `IllegalStateException` if it is not.
`Unit`	`assertNotInLayoutOrScroll(message: String!)` Checks if RecyclerView is in the middle of a layout or scroll and throws an `IllegalStateException` if it is.
`Unit`	`attachView(child: View)` Reattach a previously `detached` view.
`Unit`	`attachView(child: View, index: Int)` Reattach a previously `detached` view.
`Unit`	`attachView(child: View, index: Int, lp: RecyclerView.LayoutParams!)` Reattach a previously `detached` view.
`Unit`	`calculateItemDecorationsForChild(child: View, outRect: Rect)` Calculates the item decor insets applied to the given child and updates the provided Rect instance with the inset values.
`java-static Int`	`chooseSize(spec: Int, desired: Int, min: Int)` Chooses a size from the given specs and parameters that is closest to the desired size and also complies with the spec.
`Int`	`computeHorizontalScrollExtent(state: RecyclerView.State)` Override this method if you want to support scroll bars.
`Int`	`computeHorizontalScrollOffset(state: RecyclerView.State)` Override this method if you want to support scroll bars.
`Int`	`computeHorizontalScrollRange(state: RecyclerView.State)` Override this method if you want to support scroll bars.
`Int`	`computeVerticalScrollExtent(state: RecyclerView.State)` Override this method if you want to support scroll bars.
`Int`	`computeVerticalScrollOffset(state: RecyclerView.State)` Override this method if you want to support scroll bars.
`Int`	`computeVerticalScrollRange(state: RecyclerView.State)` Override this method if you want to support scroll bars.
`Unit`	`detachAndScrapAttachedViews(recycler: RecyclerView.Recycler)` Temporarily detach and scrap all currently attached child views.
`Unit`	`detachAndScrapView(child: View, recycler: RecyclerView.Recycler)` Detach a child view and add it to a `Recycler's` scrap heap.
`Unit`	`detachAndScrapViewAt(index: Int, recycler: RecyclerView.Recycler)` Detach a child view and add it to a `Recycler's` scrap heap.
`Unit`	`detachView(child: View)` Temporarily detach a child view.
`Unit`	`detachViewAt(index: Int)` Temporarily detach a child view.
`Unit`	`endAnimation(view: View!)` Ends all animations on the view created by the `ItemAnimator`.
`View?`	`findContainingItemView(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.
`View?`	`findViewByPosition(position: Int)` 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(child: View)` Returns the total height of item decorations applied to child's bottom.
`View?`	`getChildAt(index: Int)` Return the child view at the given index
`Int`	`getChildCount()` Return the current number of child views attached to the parent RecyclerView.
`java-static Int`	`getChildMeasureSpec( parentSize: Int, padding: Int, childDimension: Int, canScroll: Boolean )` This function is deprecated. use `getChildMeasureSpec`
`java-static Int`	`getChildMeasureSpec( parentSize: Int, parentMode: Int, padding: Int, childDimension: Int, canScroll: Boolean )` Calculate a MeasureSpec value for measuring a child view in one dimension.
`Boolean`	`getClipToPadding()` Check if the RecyclerView is configured to clip child views to its padding.
`Int`	`getDecoratedMeasuredHeight(child: View)` Returns the measured height of the given child, plus the additional size of any insets applied by `ItemDecorations`.
`Int`	`getDecoratedMeasuredWidth(child: View)` Returns the measured width of the given child, plus the additional size of any insets applied by `ItemDecorations`.
`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(view: View)` Returns the View type defined by the adapter.
`Int`	`getLayoutDirection()` Returns the resolved layout direction for this RecyclerView.
`Int`	`getLeftDecorationWidth(child: View)` 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(view: View)` Returns the adapter position of the item represented by the given View.
`java-static RecyclerView.LayoutManager.Properties!`	`getProperties( context: Context, attrs: AttributeSet?, defStyleAttr: Int, defStyleRes: Int )` Parse the xml attributes to get the most common properties used by layout managers.
`Int`	`getRightDecorationWidth(child: View)` Returns the total width of item decorations applied to child's right.
`Int`	`getSelectionModeForAccessibility( recycler: RecyclerView.Recycler, state: RecyclerView.State )` Returns the selection mode for accessibility.
`Int`	`getTopDecorationHeight(child: View)` Returns the total height of item decorations applied to child's top.
`Unit`	`getTransformedBoundingBox( child: View, includeDecorInsets: Boolean, out: Rect )` 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.
`Unit`	`ignoreView(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`	`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`	`isFocused()` Returns true if the RecyclerView this LayoutManager is bound to has focus.
`Boolean`	`isItemPrefetchEnabled()` Sets whether the LayoutManager should be queried for views outside of its viewport while the UI thread is idle between frames.
`Boolean`	`isLayoutHierarchical( recycler: RecyclerView.Recycler, state: RecyclerView.State )` Returns whether layout is hierarchical or not to be used for accessibility.
`Boolean`	`isLayoutReversed()` Query if the layout is in reverse order.
`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( child: View, completelyVisible: Boolean, acceptEndPointInclusion: Boolean )` Returns whether the given child view is partially or fully visible within the padded bounded area of RecyclerView, depending on the input parameters.
`Unit`	`layoutDecorated(child: View, left: Int, top: Int, right: Int, bottom: Int)` Lay out the given child view within the RecyclerView using coordinates that include any current `ItemDecorations`.
`Unit`	`layoutDecoratedWithMargins( child: View, left: Int, top: Int, right: Int, bottom: Int )` Lay out the given child view within the RecyclerView using coordinates that include any current `ItemDecorations` and margins.
`Unit`	`measureChild(child: View, widthUsed: Int, heightUsed: Int)` Measure a child view using standard measurement policy, taking the padding of the parent RecyclerView and any added item decorations into account.
`Unit`	`measureChildWithMargins(child: View, widthUsed: Int, heightUsed: Int)` Measure a child view using standard measurement policy, taking the padding of the parent RecyclerView, any added item decorations and the child margins into account.
`Unit`	`moveView(fromIndex: Int, toIndex: Int)` Moves a View from one position to another.
`Unit`	`offsetChildrenHorizontal(dx: @Px Int)` Offset all child views attached to the parent RecyclerView by dx pixels along the horizontal axis.
`Unit`	`offsetChildrenVertical(dy: @Px Int)` Offset all child views attached to the parent RecyclerView by dy pixels along the vertical axis.
`Unit`	`@CallSuper onAttachedToWindow(view: RecyclerView!)` Called when this LayoutManager is both attached to a RecyclerView and that RecyclerView is attached to a window.
`Unit`	`onDetachedFromWindow(view: RecyclerView!)` This function is deprecated. override `onDetachedFromWindow`
`Unit`	`@CallSuper onDetachedFromWindow(view: RecyclerView!, recycler: RecyclerView.Recycler!)` Called when this LayoutManager is detached from its parent RecyclerView or when its parent RecyclerView is detached from its window.
`View?`	`onFocusSearchFailed( focused: View, direction: Int, recycler: RecyclerView.Recycler, state: RecyclerView.State )` Called when searching for a focusable view in the given direction has failed for the current content of the RecyclerView.
`Unit`	`onInitializeAccessibilityEvent(event: AccessibilityEvent)`
`Unit`	`onInitializeAccessibilityEvent( recycler: RecyclerView.Recycler, state: RecyclerView.State, event: AccessibilityEvent )` Called by the accessibility delegate to initialize an accessibility event.
`Unit`	`onItemsUpdated( recyclerView: RecyclerView, positionStart: Int, itemCount: Int, payload: Any? )` Called when items have been changed in the adapter and with optional payload.
`Boolean`	`onRequestChildFocus(parent: RecyclerView, child: View, focused: View?)` This function is deprecated. Use `onRequestChildFocus`
`Unit`	`onScrollStateChanged(state: Int)` RecyclerView calls this method to notify LayoutManager that scroll state has changed.
`Boolean`	`performAccessibilityActionForItem( recycler: RecyclerView.Recycler, state: RecyclerView.State, view: View, action: Int, args: Bundle? )` Called by AccessibilityDelegate when an accessibility action is requested on one of the children of LayoutManager.
`Unit`	`postOnAnimation(action: Runnable!)` Causes the Runnable to execute on the next animation time step.
`Unit`	`removeAllViews()` Remove all views from the currently attached RecyclerView.
`Unit`	`removeAndRecycleView(child: View, recycler: RecyclerView.Recycler)` Remove a child view and recycle it using the given Recycler.
`Unit`	`removeAndRecycleViewAt(index: Int, recycler: RecyclerView.Recycler)` Remove a child view and recycle it using the given Recycler.
`Boolean`	`removeCallbacks(action: Runnable!)` Removes the specified Runnable from the message queue.
`Unit`	`removeDetachedView(child: View)` Finish removing a view that was previously temporarily `detached`.
`Unit`	`removeView(child: View!)` Remove a view from the currently attached RecyclerView if needed.
`Unit`	`removeViewAt(index: Int)` Remove a view from the currently attached RecyclerView if needed.
`Boolean`	`requestChildRectangleOnScreen( parent: RecyclerView, child: View, rect: Rect, immediate: Boolean, focusedChildVisible: Boolean )` Requests that the given child of the RecyclerView be positioned onto the screen.
`Unit`	`requestLayout()` Calls `RecyclerView#requestLayout` on the underlying RecyclerView
`Unit`	`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.
`Unit`	`setAutoMeasureEnabled(enabled: Boolean)` This function is deprecated. Implementors of LayoutManager should define whether or not it uses AutoMeasure by overriding `isAutoMeasureEnabled`.
`Unit`	`setItemPrefetchEnabled(enabled: Boolean)` Sets whether the LayoutManager should be queried for views outside of its viewport while the UI thread is idle between frames.
`Unit`	`setMeasuredDimension(widthSize: Int, heightSize: Int)` `Set the measured dimensions` of the host RecyclerView.
`Unit`	`setMeasuredDimension(childrenBounds: Rect!, wSpec: Int, hSpec: Int)` Sets the measured dimensions from the given bounding box of the children and the measurement specs that were passed into `onMeasure`.
`Unit`	`setMeasurementCacheEnabled(measurementCacheEnabled: Boolean)` Sets whether RecyclerView should use its own measurement cache for the children.
`Unit`	`stopIgnoringView(view: View)` View can be scrapped and recycled again.

Public constructors

GridLayoutManager

Added in 1.0.0-alpha03

GridLayoutManager()

Public functions

canScrollHorizontally

fun canScrollHorizontally(): Boolean

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

fun canScrollVertically(): Boolean

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

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

fun checkLayoutParams(lp: RecyclerView.LayoutParams?): Boolean

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
`lp: RecyclerView.LayoutParams?`	LayoutParams object to check

Returns
`Boolean`	true if this LayoutParams object is valid, false otherwise

fun collectAdjacentPrefetchPositions(
    dx: Int,
    dy: Int,
    state: RecyclerView.State,
    layoutPrefetchRegistry: RecyclerView.LayoutManager.LayoutPrefetchRegistry
): Unit

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

If item prefetch is enabled, this method is called in between traversals to gather which positions the LayoutManager will soon need, given upcoming movement in subsequent traversals.

The LayoutManager should call addPosition for each item to be prepared, and these positions will have their ViewHolders created and bound, if there is sufficient time available, in advance of being needed by a scroll or layout.

Parameters
`dx: Int`	X movement component.
`dy: Int`	Y movement component.
`state: RecyclerView.State`	State of RecyclerView
`layoutPrefetchRegistry: RecyclerView.LayoutManager.LayoutPrefetchRegistry`	PrefetchRegistry to add prefetch entries into.

See also
`isItemPrefetchEnabled`
`collectInitialPrefetchPositions`

fun collectInitialPrefetchPositions(
    adapterItemCount: Int,
    layoutPrefetchRegistry: RecyclerView.LayoutManager.LayoutPrefetchRegistry
): Unit

Gather all positions from the LayoutManager to be prefetched in preperation for its RecyclerView to come on screen, due to the movement of another, containing RecyclerView.

This method is only called when a RecyclerView is nested in another RecyclerView.

If item prefetch is enabled for this LayoutManager, as well in another containing LayoutManager, this method is called in between draw traversals to gather which positions this LayoutManager will first need, once it appears on the screen.

For example, if this LayoutManager represents a horizontally scrolling list within a vertically scrolling LayoutManager, this method would be called when the horizontal list is about to come onscreen.

Parameters
`adapterItemCount: Int`	number of items in the associated adapter.
`layoutPrefetchRegistry: RecyclerView.LayoutManager.LayoutPrefetchRegistry`	PrefetchRegistry to add prefetch entries into.

See also
`isItemPrefetchEnabled`
`collectAdjacentPrefetchPositions`

generateDefaultLayoutParams

Added in 1.0.0-alpha03

fun generateDefaultLayoutParams(): RecyclerView.LayoutParams

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

fun generateLayoutParams(lp: ViewGroup.LayoutParams): RecyclerView.LayoutParams

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

generateLayoutParams

fun generateLayoutParams(context: Context, attrs: AttributeSet): RecyclerView.LayoutParams

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

fun getColumnCountForAccessibility(
    recycler: RecyclerView.Recycler,
    state: RecyclerView.State
): Int

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
`recycler: RecyclerView.Recycler`	The Recycler that can be used to convert view positions into adapter positions
`state: RecyclerView.State`	The current state of RecyclerView

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

getDecoratedBottom

fun getDecoratedBottom(child: View): Int

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

Parameters
`child: View`	Child to query

Returns
`Int`	Child bottom edge with offsets applied

See also
`getBottomDecorationHeight`

getDecoratedBoundsWithMargins

fun getDecoratedBoundsWithMargins(view: View, outBounds: Rect): Unit

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

Parameters
`view: View`	The view element to check
`outBounds: Rect`	A rect that will receive the bounds of the element including its decoration and margins.

getDecoratedLeft

fun getDecoratedLeft(child: View): Int

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

Parameters
`child: View`	Child to query

Returns
`Int`	Child left edge with offsets applied

See also
`getLeftDecorationWidth`

getDecoratedRight

fun getDecoratedRight(child: View): Int

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

Parameters
`child: View`	Child to query

Returns
`Int`	Child right edge with offsets applied

See also
`getRightDecorationWidth`

getDecoratedTop

fun getDecoratedTop(child: View): Int

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

Parameters
`child: View`	Child to query

Returns
`Int`	Child top edge with offsets applied

See also
`getTopDecorationHeight`

fun getRowCountForAccessibility(
    recycler: RecyclerView.Recycler,
    state: RecyclerView.State
): Int

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
`recycler: RecyclerView.Recycler`	The Recycler that can be used to convert view positions into adapter positions
`state: RecyclerView.State`	The current state of RecyclerView

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

fun onAdapterChanged(
    oldAdapter: RecyclerView.Adapter?,
    newAdapter: RecyclerView.Adapter?
): Unit

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

fun onAddFocusables(
    recyclerView: RecyclerView,
    views: ArrayList<View!>,
    direction: Int,
    focusableMode: Int
): Boolean

Called to populate focusable views within the RecyclerView.

The LayoutManager implementation should return true if the default behavior of addFocusables should be suppressed.

The default implementation returns false to trigger RecyclerView to fall back to the default ViewGroup behavior.

Parameters
`recyclerView: RecyclerView`	The RecyclerView hosting this LayoutManager
`views: ArrayList<View!>`	List of output views. This method should add valid focusable views to this list.
`direction: Int`	One of `FOCUS_UP`, `FOCUS_DOWN`, `FOCUS_LEFT`, `FOCUS_RIGHT`, `FOCUS_BACKWARD`, `FOCUS_FORWARD`
`focusableMode: Int`	The type of focusables to be added.

Returns
`Boolean`	true to suppress the default behavior, false to add default focusables after this method returns.

See also
`FOCUSABLES_ALL`
`FOCUSABLES_TOUCH_MODE`

fun onInitializeAccessibilityNodeInfo(
    recycler: RecyclerView.Recycler,
    state: RecyclerView.State,
    info: AccessibilityNodeInfoCompat
): Unit

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
`recycler: RecyclerView.Recycler`	The Recycler that can be used to convert view positions into adapter positions
`state: RecyclerView.State`	The current state of RecyclerView
`info: AccessibilityNodeInfoCompat`	The info that should be filled by the LayoutManager

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

fun onInitializeAccessibilityNodeInfoForItem(
    recycler: RecyclerView.Recycler,
    state: RecyclerView.State,
    host: View,
    info: AccessibilityNodeInfoCompat
): Unit

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
`recycler: RecyclerView.Recycler`	The Recycler that can be used to convert view positions into adapter positions
`state: RecyclerView.State`	The current state of RecyclerView
`host: View`	The child for which accessibility node info should be populated
`info: AccessibilityNodeInfoCompat`	The info to fill out about the item

See also
`onInitializeAccessibilityNodeInfoForItem`

onInterceptFocusSearch

fun onInterceptFocusSearch(focused: View?, direction: Int): View?

This method gives a LayoutManager an opportunity to intercept the initial focus search before the default behavior of FocusFinder is used. If this method returns null FocusFinder will attempt to find a focusable child view. If it fails then onFocusSearchFailed will be called to give the LayoutManager an opportunity to add new views for items that did not have attached views representing them. The LayoutManager should not add or remove views from this method.

Parameters
`focused: View?`	The currently focused view
`direction: Int`	One of `FOCUS_UP`, `FOCUS_DOWN`, `FOCUS_LEFT`, `FOCUS_RIGHT`, `FOCUS_BACKWARD`, `FOCUS_FORWARD`

Returns
`View?`	A descendant view to focus or null to fall back to default behavior. The default implementation returns null.

fun onItemsAdded(
    recyclerView: RecyclerView,
    positionStart: Int,
    itemCount: Int
): Unit

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.)

fun onItemsChanged(recyclerView: RecyclerView): Unit

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

fun onItemsMoved(
    recyclerView: RecyclerView,
    fromPosition: Int,
    toPosition: Int,
    itemCount: Int
): Unit

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.

fun onItemsRemoved(
    recyclerView: RecyclerView,
    positionStart: Int,
    itemCount: Int
): Unit

Called when items have been removed from the adapter.

fun onItemsUpdated(
    recyclerView: RecyclerView,
    positionStart: Int,
    itemCount: Int
): Unit

Called when items have been changed in the adapter. To receive payload, override onItemsUpdated instead, then this callback will not be invoked.

fun onLayoutChildren(
    recycler: RecyclerView.Recycler,
    state: RecyclerView.State
): Unit

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

fun onLayoutCompleted(state: RecyclerView.State): Unit

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
`state: RecyclerView.State`	Transient state of RecyclerView

fun onMeasure(
    recycler: RecyclerView.Recycler,
    state: RecyclerView.State,
    widthSpec: Int,
    heightSpec: Int
): Unit

Measure the attached RecyclerView. Implementations must call setMeasuredDimension before returning.

It is strongly advised to use the AutoMeasure mechanism by overriding isAutoMeasureEnabled to return true as AutoMeasure handles all the standard measure cases including when the RecyclerView's layout_width or layout_height have been set to wrap_content. If isAutoMeasureEnabled is overridden to return true, this method should not be overridden.

The default implementation will handle EXACTLY measurements and respect the minimum width and height properties of the host RecyclerView if measured as UNSPECIFIED. AT_MOST measurements will be treated as EXACTLY and the RecyclerView will consume all available space.

Parameters
`recycler: RecyclerView.Recycler`	Recycler
`state: RecyclerView.State`	Transient state of RecyclerView
`widthSpec: Int`	Width `android.view.View.MeasureSpec`
`heightSpec: Int`	Height `android.view.View.MeasureSpec`

See also
`isAutoMeasureEnabled`
`setMeasuredDimension`

fun onRequestChildFocus(
    parent: RecyclerView,
    state: RecyclerView.State,
    child: View,
    focused: View?
): Boolean

Called when a descendant view of the RecyclerView requests focus.

A LayoutManager wishing to keep focused views aligned in a specific portion of the view may implement that behavior in an override of this method.

If the LayoutManager executes different behavior that should override the default behavior of scrolling the focused child on screen instead of running alongside it, this method should return true.

Parameters
`parent: RecyclerView`	The RecyclerView hosting this LayoutManager
`state: RecyclerView.State`	Current state of RecyclerView
`child: View`	Direct child of the RecyclerView containing the newly focused view
`focused: View?`	The newly focused view. This may be the same view as child or it may be null

Returns
`Boolean`	true if the default scroll behavior should be suppressed

onRestoreInstanceState

fun onRestoreInstanceState(state: Parcelable?): Unit

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
`state: Parcelable?`	The parcelable that was returned by the previous LayoutManager's `onSaveInstanceState` method.

onSaveInstanceState

fun onSaveInstanceState(): Parcelable

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

fun performAccessibilityAction(
    recycler: RecyclerView.Recycler,
    state: RecyclerView.State,
    action: Int,
    args: Bundle?
): Boolean

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

Parameters
`recycler: RecyclerView.Recycler`	The Recycler that can be used to convert view positions into adapter positions
`state: RecyclerView.State`	The current state of RecyclerView
`action: Int`	The action to perform
`args: Bundle?`	Optional action arguments

See also
`performAccessibilityAction`

fun removeAndRecycleAllViews(recycler: RecyclerView.Recycler): Unit

Removes all views and recycles them using the given recycler.

If you want to clean cached views as well, you should call clear too.

If a View is marked as "ignored", it is not removed nor recycled.

Parameters
`recycler: RecyclerView.Recycler`	Recycler to use to recycle children

See also
`removeAndRecycleView`
`removeAndRecycleViewAt`
`ignoreView`

fun requestChildRectangleOnScreen(
    parent: RecyclerView,
    child: View,
    rect: Rect,
    immediate: Boolean
): Boolean

Called when a child of the RecyclerView wants a particular rectangle to be positioned onto the screen. See requestChildRectangleOnScreen for more details.

The base implementation will attempt to perform a standard programmatic scroll to bring the given rect into view, within the padded area of the RecyclerView.

Parameters
`parent: RecyclerView`	The parent RecyclerView.
`child: View`	The direct child making the request.
`rect: Rect`	The rectangle in the child's coordinates the child wishes to be on the screen.
`immediate: Boolean`	True to forbid animated or delayed scrolling, false otherwise

Returns
`Boolean`	Whether the group scrolled to handle the operation

fun scrollHorizontallyBy(
    dx: Int,
    recycler: RecyclerView.Recycler,
    state: RecyclerView.State
): Int

Scroll horizontally by dx pixels in screen coordinates and return the distance traveled. The default implementation does nothing and returns 0.

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

fun scrollToPosition(position: Int): Unit

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

Parameters
`position: Int`	Scroll to this adapter position.

fun scrollVerticallyBy(
    dy: Int,
    recycler: RecyclerView.Recycler,
    state: RecyclerView.State
): Int

Scroll vertically by dy pixels in screen coordinates and return the distance traveled. The default implementation does nothing and returns 0.

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

setFocusOutAllowed

Added in 1.0.0-alpha03

fun setFocusOutAllowed(throughFront: Boolean, throughBack: Boolean): Unit

Sets whether focus can move out from the front and/or back of the grid view.

Parameters
`throughFront: Boolean`	For the vertical orientation, this controls whether focus can move out from the top of the grid. For the horizontal orientation, this controls whether focus can move out the front side of the grid.
`throughBack: Boolean`	For the vertical orientation, this controls whether focus can move out from the bottom of the grid. For the horizontal orientation, this controls whether focus can move out the back side of the grid.

setOrientation

Added in 1.0.0-alpha03

fun setOrientation(orientation: Int): Unit

Sets grid view orientation.

fun smoothScrollToPosition(
    recyclerView: RecyclerView,
    state: RecyclerView.State,
    position: Int
): Unit

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
`state: RecyclerView.State`	Current State of RecyclerView
`position: Int`	Scroll to this adapter position.

fun startSmoothScroll(smoothScroller: RecyclerView.SmoothScroller): Unit

Starts a smooth scroll using the provided SmoothScroller.

Each instance of SmoothScroller is intended to only be used once. Provide a new SmoothScroller instance each time this method is called.

Calling this method will cancel any previous smooth scroll request.

Parameters
`smoothScroller: RecyclerView.SmoothScroller`	Instance which defines how smooth scroll should be animated

supportsPredictiveItemAnimations

fun supportsPredictiveItemAnimations(): Boolean

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.