added in version 22.1.0
belongs to Maven artifact com.android.support:recyclerview-v7:28.0.0-alpha1
Summary: Nested Classes | XML Attrs | Constants | Inherited Constants | Inherited Fields | Ctors | Methods | Protected Methods | Inherited Methods | [Expand All]

RecyclerView

public class RecyclerView
extends ViewGroup implements ScrollingView, NestedScrollingChild2

java.lang.Object
   ↳ android.view.View
     ↳ android.view.ViewGroup
       ↳ android.support.v7.widget.RecyclerView
Known Direct Subclasses
Known Indirect Subclasses

A flexible view for providing a limited window into a large data set.

Glossary of terms:

  • Adapter: A subclass of RecyclerView.Adapter responsible for providing views that represent items in a data set.
  • Position: The position of a data item within an Adapter.
  • Index: The index of an attached child view as used in a call to getChildAt(int). Contrast with Position.
  • Binding: The process of preparing a child view to display data corresponding to a position within the adapter.
  • Recycle (view): A view previously used to display data for a specific adapter position may be placed in a cache for later reuse to display the same type of data again later. This can drastically improve performance by skipping initial layout inflation or construction.
  • Scrap (view): A child view that has entered into a temporarily detached state during layout. Scrap views may be reused without becoming fully detached from the parent RecyclerView, either unmodified if no rebinding is required or modified by the adapter if the view was considered dirty.
  • Dirty (view): A child view that must be rebound by the adapter before being displayed.

Positions in RecyclerView:

RecyclerView introduces an additional level of abstraction between the RecyclerView.Adapter and RecyclerView.LayoutManager to be able to detect data set changes in batches during a layout calculation. This saves LayoutManager from tracking adapter changes to calculate animations. It also helps with performance because all view bindings happen at the same time and unnecessary bindings are avoided.

For this reason, there are two types of position related methods in RecyclerView:

  • layout position: Position of an item in the latest layout calculation. This is the position from the LayoutManager's perspective.
  • adapter position: Position of an item in the adapter. This is the position from the Adapter's perspective.

These two positions are the same except the time between dispatching adapter.notify* events and calculating the updated layout.

Methods that return or receive *LayoutPosition* use position as of the latest layout calculation (e.g. getLayoutPosition(), findViewHolderForLayoutPosition(int)). These positions include all changes until the last layout calculation. You can rely on these positions to be consistent with what user is currently seeing on the screen. For example, if you have a list of items on the screen and user asks for the 5th element, you should use these methods as they'll match what user is seeing.

The other set of position related methods are in the form of *AdapterPosition*. (e.g. getAdapterPosition(), findViewHolderForAdapterPosition(int)) You should use these methods when you need to work with up-to-date adapter positions even if they may not have been reflected to layout yet. For example, if you want to access the item in the adapter on a ViewHolder click, you should use getAdapterPosition(). Beware that these methods may not be able to calculate adapter positions if notifyDataSetChanged() has been called and new layout has not yet been calculated. For this reasons, you should carefully handle NO_POSITION or null results from these methods.

When writing a RecyclerView.LayoutManager you almost always want to use layout positions whereas when writing an RecyclerView.Adapter, you probably want to use adapter positions.

Summary

Nested classes

class RecyclerView.Adapter<VH extends RecyclerView.ViewHolder>

Base class for an Adapter

Adapters provide a binding from an app-specific data set to views that are displayed within a RecyclerView. 

class RecyclerView.AdapterDataObserver

Observer base class for watching changes to an RecyclerView.Adapter. 

interface RecyclerView.ChildDrawingOrderCallback

A callback interface that can be used to alter the drawing order of RecyclerView children. 

class RecyclerView.EdgeEffectFactory

EdgeEffectFactory lets you customize the over-scroll edge effect for RecyclerViews. 

class RecyclerView.ItemAnimator

This class defines the animations that take place on items as changes are made to the adapter. 

class RecyclerView.ItemDecoration

An ItemDecoration allows the application to add a special drawing and layout offset to specific item views from the adapter's data set. 

class RecyclerView.LayoutManager

A LayoutManager is responsible for measuring and positioning item views within a RecyclerView as well as determining the policy for when to recycle item views that are no longer visible to the user. 

class RecyclerView.LayoutParams

LayoutParams subclass for children of RecyclerView. 

interface RecyclerView.OnChildAttachStateChangeListener

A Listener interface that can be attached to a RecylcerView to get notified whenever a ViewHolder is attached to or detached from RecyclerView. 

class RecyclerView.OnFlingListener

This class defines the behavior of fling if the developer wishes to handle it. 

interface RecyclerView.OnItemTouchListener

An OnItemTouchListener allows the application to intercept touch events in progress at the view hierarchy level of the RecyclerView before those touch events are considered for RecyclerView's own scrolling behavior. 

class RecyclerView.OnScrollListener

An OnScrollListener can be added to a RecyclerView to receive messages when a scrolling event has occurred on that RecyclerView. 

class RecyclerView.RecycledViewPool

RecycledViewPool lets you share Views between multiple RecyclerViews. 

class RecyclerView.Recycler

A Recycler is responsible for managing scrapped or detached item views for reuse. 

interface RecyclerView.RecyclerListener

A RecyclerListener can be set on a RecyclerView to receive messages whenever a view is recycled. 

class RecyclerView.SimpleOnItemTouchListener

An implementation of RecyclerView.OnItemTouchListener that has empty method bodies and default return values. 

class RecyclerView.SmoothScroller

Base class for smooth scrolling. 

class RecyclerView.State

Contains useful information about the current RecyclerView state like target scroll position or view focus. 

class RecyclerView.ViewCacheExtension

ViewCacheExtension is a helper class to provide an additional layer of view caching that can be controlled by the developer. 

class RecyclerView.ViewHolder

A ViewHolder describes an item view and metadata about its place within the RecyclerView. 

XML attributes

RecyclerView_layoutManager  

Constants

int HORIZONTAL

int INVALID_TYPE

long NO_ID

int NO_POSITION

int SCROLL_STATE_DRAGGING

The RecyclerView is currently being dragged by outside input such as user touch input.

int SCROLL_STATE_IDLE

The RecyclerView is not currently scrolling.

int SCROLL_STATE_SETTLING

The RecyclerView is currently animating to a final position while not under outside control.

int TOUCH_SLOP_DEFAULT

Constant for use with setScrollingTouchSlop(int).

int TOUCH_SLOP_PAGING

Constant for use with setScrollingTouchSlop(int).

int VERTICAL

Inherited constants

From class android.view.ViewGroup
From class android.view.View

Inherited fields

From class android.view.View

Public constructors

RecyclerView(Context context)
RecyclerView(Context context, AttributeSet attrs)
RecyclerView(Context context, AttributeSet attrs, int defStyle)

Public methods

void addFocusables(ArrayList<View> views, int direction, int focusableMode)
void addItemDecoration(RecyclerView.ItemDecoration decor)

Add an RecyclerView.ItemDecoration to this RecyclerView.

void addItemDecoration(RecyclerView.ItemDecoration decor, int index)

Add an RecyclerView.ItemDecoration to this RecyclerView.

void addOnChildAttachStateChangeListener(RecyclerView.OnChildAttachStateChangeListener listener)

Register a listener that will be notified whenever a child view is attached to or detached from RecyclerView.

void addOnItemTouchListener(RecyclerView.OnItemTouchListener listener)

Add an RecyclerView.OnItemTouchListener to intercept touch events before they are dispatched to child views or this view's standard scrolling behavior.

void addOnScrollListener(RecyclerView.OnScrollListener listener)

Add a listener that will be notified of any changes in scroll state or position.

void clearOnChildAttachStateChangeListeners()

Removes all listeners that were added via addOnChildAttachStateChangeListener(OnChildAttachStateChangeListener).

void clearOnScrollListeners()

Remove all secondary listener that were notified of any changes in scroll state or position.

int computeHorizontalScrollExtent()

Compute the horizontal extent of the horizontal scrollbar's thumb within the horizontal range.

int computeHorizontalScrollOffset()

Compute the horizontal offset of the horizontal scrollbar's thumb within the horizontal range.

int computeHorizontalScrollRange()

Compute the horizontal range that the horizontal scrollbar represents.

int computeVerticalScrollExtent()

Compute the vertical extent of the vertical scrollbar's thumb within the vertical range.

int computeVerticalScrollOffset()

Compute the vertical offset of the vertical scrollbar's thumb within the vertical range.

int computeVerticalScrollRange()

Compute the vertical range that the vertical scrollbar represents.

boolean dispatchNestedFling(float velocityX, float velocityY, boolean consumed)
boolean dispatchNestedPreFling(float velocityX, float velocityY)
boolean dispatchNestedPreScroll(int dx, int dy, int[] consumed, int[] offsetInWindow)
boolean dispatchNestedPreScroll(int dx, int dy, int[] consumed, int[] offsetInWindow, int type)

Dispatch one step of a nested scroll in progress before this view consumes any portion of it.

boolean dispatchNestedScroll(int dxConsumed, int dyConsumed, int dxUnconsumed, int dyUnconsumed, int[] offsetInWindow, int type)

Dispatch one step of a nested scroll in progress.

boolean dispatchNestedScroll(int dxConsumed, int dyConsumed, int dxUnconsumed, int dyUnconsumed, int[] offsetInWindow)
void draw(Canvas c)
boolean drawChild(Canvas canvas, View child, long drawingTime)
View findChildViewUnder(float x, float y)

Find the topmost view under the given point.

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 RecyclerView.

RecyclerView.ViewHolder findContainingViewHolder(View view)

Returns the ViewHolder that contains the given view.

RecyclerView.ViewHolder findViewHolderForAdapterPosition(int position)

Return the ViewHolder for the item in the given position of the data set.

RecyclerView.ViewHolder findViewHolderForItemId(long id)

Return the ViewHolder for the item with the given id.

RecyclerView.ViewHolder findViewHolderForLayoutPosition(int position)

Return the ViewHolder for the item in the given position of the data set as of the latest layout pass.

RecyclerView.ViewHolder findViewHolderForPosition(int position)

This method was deprecated in API level 22.1.0. use findViewHolderForLayoutPosition(int) or findViewHolderForAdapterPosition(int)

boolean fling(int velocityX, int velocityY)

Begin a standard fling with an initial velocity along each axis in pixels per second.

View focusSearch(View focused, int direction)

Since RecyclerView is a collection ViewGroup that includes virtual children (items that are in the Adapter but not visible in the UI), it employs a more involved focus search strategy that differs from other ViewGroups.

ViewGroup.LayoutParams generateLayoutParams(AttributeSet attrs)
Adapter getAdapter()

Retrieves the previously set adapter or null if no adapter is set.

int getBaseline()

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

int getChildAdapterPosition(View child)

Return the adapter position that the given child view corresponds to.

long getChildItemId(View child)

Return the stable item id that the given child view corresponds to.

int getChildLayoutPosition(View child)

Return the adapter position of the given child view as of the latest completed layout pass.

int getChildPosition(View child)

This method was deprecated in API level 22.1.0. use getChildAdapterPosition(View) or getChildLayoutPosition(View).

RecyclerView.ViewHolder getChildViewHolder(View child)

Retrieve the RecyclerView.ViewHolder for the given child view.

boolean getClipToPadding()

Returns whether this RecyclerView will clip its children to its padding, and resize (but not clip) any EdgeEffect to the padded region, if padding is present.

RecyclerViewAccessibilityDelegate getCompatAccessibilityDelegate()

Returns the accessibility delegate compatibility implementation used by the RecyclerView.

void getDecoratedBoundsWithMargins(View view, Rect outBounds)

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

RecyclerView.EdgeEffectFactory getEdgeEffectFactory()

Retrieves the previously set RecyclerView.EdgeEffectFactory or the default factory if nothing was set.

RecyclerView.ItemAnimator getItemAnimator()

Gets the current ItemAnimator for this RecyclerView.

RecyclerView.ItemDecoration getItemDecorationAt(int index)

Returns an RecyclerView.ItemDecoration previously added to this RecyclerView.

int getItemDecorationCount()

Returns the number of RecyclerView.ItemDecoration currently added to this RecyclerView.

RecyclerView.LayoutManager getLayoutManager()

Return the RecyclerView.LayoutManager currently responsible for layout policy for this RecyclerView.

int getMaxFlingVelocity()

Returns the maximum fling velocity used by this RecyclerView.

int getMinFlingVelocity()

Returns the minimum velocity to start a fling.

RecyclerView.OnFlingListener getOnFlingListener()

Get the current RecyclerView.OnFlingListener from this RecyclerView.

boolean getPreserveFocusAfterLayout()

Returns true if the RecyclerView should attempt to preserve currently focused Adapter Item's focus even if the View representing the Item is replaced during a layout calculation.

RecyclerView.RecycledViewPool getRecycledViewPool()

Retrieve this RecyclerView's RecyclerView.RecycledViewPool.

int getScrollState()

Return the current scrolling state of the RecyclerView.

boolean hasFixedSize()
boolean hasNestedScrollingParent()
boolean hasNestedScrollingParent(int type)

Returns true if this view has a nested scrolling parent for the given input type.

boolean hasPendingAdapterUpdates()

Returns whether there are pending adapter updates which are not yet applied to the layout.

void invalidateItemDecorations()

Invalidates all ItemDecorations.

boolean isAnimating()

Returns true if RecyclerView is currently running some animations.

boolean isAttachedToWindow()

Returns true if RecyclerView is attached to window.

boolean isComputingLayout()

Returns whether RecyclerView is currently computing a layout.

boolean isLayoutFrozen()

Returns true if layout and scroll are frozen.

boolean isNestedScrollingEnabled()
void offsetChildrenHorizontal(int dx)

Offset the bounds of all child views by dx pixels.

void offsetChildrenVertical(int dy)

Offset the bounds of all child views by dy pixels.

void onChildAttachedToWindow(View child)

Called when an item view is attached to this RecyclerView.

void onChildDetachedFromWindow(View child)

Called when an item view is detached from this RecyclerView.

void onDraw(Canvas c)
boolean onGenericMotionEvent(MotionEvent event)
boolean onInterceptTouchEvent(MotionEvent e)
void onScrollStateChanged(int state)

Called when the scroll state of this RecyclerView changes.

void onScrolled(int dx, int dy)

Called when the scroll position of this RecyclerView changes.

boolean onTouchEvent(MotionEvent e)
void removeItemDecoration(RecyclerView.ItemDecoration decor)

Remove an RecyclerView.ItemDecoration from this RecyclerView.

void removeItemDecorationAt(int index)

Removes the RecyclerView.ItemDecoration associated with the supplied index position.

void removeOnChildAttachStateChangeListener(RecyclerView.OnChildAttachStateChangeListener listener)

Removes the provided listener from child attached state listeners list.

void removeOnItemTouchListener(RecyclerView.OnItemTouchListener listener)

Remove an RecyclerView.OnItemTouchListener.

void removeOnScrollListener(RecyclerView.OnScrollListener listener)

Remove a listener that was notified of any changes in scroll state or position.

void requestChildFocus(View child, View focused)
boolean requestChildRectangleOnScreen(View child, Rect rect, boolean immediate)
void requestDisallowInterceptTouchEvent(boolean disallowIntercept)
void requestLayout()
void scrollBy(int x, int y)
void scrollTo(int x, int y)
void scrollToPosition(int position)

Convenience method to scroll to a certain position.

void sendAccessibilityEventUnchecked(AccessibilityEvent event)
void setAccessibilityDelegateCompat(RecyclerViewAccessibilityDelegate accessibilityDelegate)

Sets the accessibility delegate compatibility implementation used by RecyclerView.

void setAdapter(Adapter adapter)

Set a new adapter to provide child views on demand.

void setChildDrawingOrderCallback(RecyclerView.ChildDrawingOrderCallback childDrawingOrderCallback)

Sets the RecyclerView.ChildDrawingOrderCallback to be used for drawing children.

void setClipToPadding(boolean clipToPadding)
void setEdgeEffectFactory(RecyclerView.EdgeEffectFactory edgeEffectFactory)

Set a RecyclerView.EdgeEffectFactory for this RecyclerView.

void setHasFixedSize(boolean hasFixedSize)

RecyclerView can perform several optimizations if it can know in advance that RecyclerView's size is not affected by the adapter contents.

void setItemAnimator(RecyclerView.ItemAnimator animator)

Sets the RecyclerView.ItemAnimator that will handle animations involving changes to the items in this RecyclerView.

void setItemViewCacheSize(int size)

Set the number of offscreen views to retain before adding them to the potentially shared recycled view pool.

void setLayoutFrozen(boolean frozen)

Enable or disable layout and scroll.

void setLayoutManager(RecyclerView.LayoutManager layout)

Set the RecyclerView.LayoutManager that this RecyclerView will use.

void setNestedScrollingEnabled(boolean enabled)
void setOnFlingListener(RecyclerView.OnFlingListener onFlingListener)

Set a RecyclerView.OnFlingListener for this RecyclerView.

void setOnScrollListener(RecyclerView.OnScrollListener listener)

This method was deprecated in API level 22.1.0. Use addOnScrollListener(OnScrollListener) and removeOnScrollListener(OnScrollListener)

void setPreserveFocusAfterLayout(boolean preserveFocusAfterLayout)

Set whether the RecyclerView should try to keep the same Item focused after a layout calculation or not.

void setRecycledViewPool(RecyclerView.RecycledViewPool pool)

Recycled view pools allow multiple RecyclerViews to share a common pool of scrap views.

void setRecyclerListener(RecyclerView.RecyclerListener listener)

Register a listener that will be notified whenever a child view is recycled.

void setScrollingTouchSlop(int slopConstant)

Configure the scrolling touch slop for a specific use case.

void setViewCacheExtension(RecyclerView.ViewCacheExtension extension)

Sets a new RecyclerView.ViewCacheExtension to be used by the Recycler.

void smoothScrollBy(int dx, int dy)

Animate a scroll by the given amount of pixels along either axis.

void smoothScrollBy(int dx, int dy, Interpolator interpolator)

Animate a scroll by the given amount of pixels along either axis.

void smoothScrollToPosition(int position)

Starts a smooth scroll to an adapter position.

boolean startNestedScroll(int axes)
boolean startNestedScroll(int axes, int type)

Begin a nestable scroll operation along the given axes, for the given input type.

void stopNestedScroll()
void stopNestedScroll(int type)

Stop a nested scroll in progress for the given input type.

void stopScroll()

Stop any current scroll in progress, such as one started by smoothScrollBy(int, int), fling(int, int) or a touch-initiated fling.

void swapAdapter(Adapter adapter, boolean removeAndRecycleExistingViews)

Swaps the current adapter with the provided one.

Protected methods

boolean checkLayoutParams(ViewGroup.LayoutParams p)
void dispatchRestoreInstanceState(SparseArray<Parcelable> container)

Override to prevent thawing of any views created by the adapter.

void dispatchSaveInstanceState(SparseArray<Parcelable> container)

Override to prevent freezing of any views created by the adapter.

ViewGroup.LayoutParams generateDefaultLayoutParams()
ViewGroup.LayoutParams generateLayoutParams(ViewGroup.LayoutParams p)
int getChildDrawingOrder(int childCount, int i)
void onAttachedToWindow()
void onDetachedFromWindow()
void onLayout(boolean changed, int l, int t, int r, int b)
void onMeasure(int widthSpec, int heightSpec)
boolean onRequestFocusInDescendants(int direction, Rect previouslyFocusedRect)
void onRestoreInstanceState(Parcelable state)
Parcelable onSaveInstanceState()
void onSizeChanged(int w, int h, int oldw, int oldh)
void removeDetachedView(View child, boolean animate)

Inherited methods

From class android.view.ViewGroup
From class android.view.View
From class java.lang.Object
From interface android.view.ViewParent
From interface android.view.ViewManager
From interface android.graphics.drawable.Drawable.Callback
From interface android.view.KeyEvent.Callback
From interface android.view.accessibility.AccessibilityEventSource
From interface android.support.v4.view.ScrollingView
From interface android.support.v4.view.NestedScrollingChild2
From interface android.support.v4.view.NestedScrollingChild

XML attributes

RecyclerView_layoutManager

Constants

HORIZONTAL

added in version 22.1.0 
int HORIZONTAL

Constant Value: 0 (0x00000000)

INVALID_TYPE

added in version 22.1.0 
int INVALID_TYPE

Constant Value: -1 (0xffffffff)

NO_ID

added in version 22.1.0 
long NO_ID

Constant Value: -1 (0xffffffffffffffff)

NO_POSITION

added in version 22.1.0 
int NO_POSITION

Constant Value: -1 (0xffffffff)

SCROLL_STATE_DRAGGING

added in version 22.1.0 
int SCROLL_STATE_DRAGGING

The RecyclerView is currently being dragged by outside input such as user touch input.

See also:

Constant Value: 1 (0x00000001)

SCROLL_STATE_IDLE

added in version 22.1.0 
int SCROLL_STATE_IDLE

The RecyclerView is not currently scrolling.

See also:

Constant Value: 0 (0x00000000)

SCROLL_STATE_SETTLING

added in version 22.1.0 
int SCROLL_STATE_SETTLING

The RecyclerView is currently animating to a final position while not under outside control.

See also:

Constant Value: 2 (0x00000002)

TOUCH_SLOP_DEFAULT

added in version 22.1.0 
int TOUCH_SLOP_DEFAULT

Constant for use with setScrollingTouchSlop(int). Indicates that the RecyclerView should use the standard touch slop for smooth, continuous scrolling.

Constant Value: 0 (0x00000000)

TOUCH_SLOP_PAGING

added in version 22.1.0 
int TOUCH_SLOP_PAGING

Constant for use with setScrollingTouchSlop(int). Indicates that the RecyclerView should use the standard touch slop for scrolling widgets that snap to a page or other coarse-grained barrier.

Constant Value: 1 (0x00000001)

VERTICAL

added in version 22.1.0 
int VERTICAL

Constant Value: 1 (0x00000001)

Public constructors

RecyclerView

added in version 22.1.0
RecyclerView (Context context)

Parameters
context Context

RecyclerView

added in version 22.1.0
RecyclerView (Context context, 
                AttributeSet attrs)

Parameters
context Context

attrs AttributeSet

RecyclerView

added in version 22.1.0
RecyclerView (Context context, 
                AttributeSet attrs, 
                int defStyle)

Parameters
context Context

attrs AttributeSet

defStyle int

Public methods

addFocusables

void addFocusables (ArrayList<View> views, 
                int direction, 
                int focusableMode)

Parameters
views ArrayList

direction int

focusableMode int

addItemDecoration

added in version 22.1.0
void addItemDecoration (RecyclerView.ItemDecoration decor)

Add an RecyclerView.ItemDecoration to this RecyclerView. Item decorations can affect both measurement and drawing of individual item views.

Item decorations are ordered. Decorations placed earlier in the list will be run/queried/drawn first for their effects on item views. Padding added to views will be nested; a padding added by an earlier decoration will mean further item decorations in the list will be asked to draw/pad within the previous decoration's given area.

Parameters
decor RecyclerView.ItemDecoration: Decoration to add

addItemDecoration

added in version 22.1.0
void addItemDecoration (RecyclerView.ItemDecoration decor, 
                int index)

Add an RecyclerView.ItemDecoration to this RecyclerView. Item decorations can affect both measurement and drawing of individual item views.

Item decorations are ordered. Decorations placed earlier in the list will be run/queried/drawn first for their effects on item views. Padding added to views will be nested; a padding added by an earlier decoration will mean further item decorations in the list will be asked to draw/pad within the previous decoration's given area.

Parameters
decor RecyclerView.ItemDecoration: Decoration to add
index int: Position in the decoration chain to insert this decoration at. If this value is negative the decoration will be added at the end.

addOnChildAttachStateChangeListener

added in version 24.1.0
void addOnChildAttachStateChangeListener (RecyclerView.OnChildAttachStateChangeListener listener)

Register a listener that will be notified whenever a child view is attached to or detached from RecyclerView.

This listener will be called when a LayoutManager or the RecyclerView decides that a child view is no longer needed. If an application associates expensive or heavyweight data with item views, this may be a good place to release or free those resources.

Parameters
listener RecyclerView.OnChildAttachStateChangeListener: Listener to register

addOnItemTouchListener

added in version 22.1.0
void addOnItemTouchListener (RecyclerView.OnItemTouchListener listener)

Add an RecyclerView.OnItemTouchListener to intercept touch events before they are dispatched to child views or this view's standard scrolling behavior.

Client code may use listeners to implement item manipulation behavior. Once a listener returns true from onInterceptTouchEvent(RecyclerView, MotionEvent) its onTouchEvent(RecyclerView, MotionEvent) method will be called for each incoming MotionEvent until the end of the gesture.

Parameters
listener RecyclerView.OnItemTouchListener: Listener to add

addOnScrollListener

added in version 22.1.0
void addOnScrollListener (RecyclerView.OnScrollListener listener)

Add a listener that will be notified of any changes in scroll state or position.

Components that add a listener should take care to remove it when finished. Other components that take ownership of a view may call clearOnScrollListeners() to remove all attached listeners.

Parameters
listener RecyclerView.OnScrollListener: listener to set

clearOnChildAttachStateChangeListeners

added in version 24.1.0
void clearOnChildAttachStateChangeListeners ()

Removes all listeners that were added via addOnChildAttachStateChangeListener(OnChildAttachStateChangeListener).

clearOnScrollListeners

added in version 22.1.0
void clearOnScrollListeners ()

Remove all secondary listener that were notified of any changes in scroll state or position.

computeHorizontalScrollExtent

added in version 22.1.0
int computeHorizontalScrollExtent ()

Compute the horizontal extent of the horizontal scrollbar's thumb within the horizontal range. This value is used to compute the length of the thumb within the scrollbar's track.

The range is expressed in arbitrary units that must be the same as the units used by computeHorizontalScrollRange() and computeHorizontalScrollOffset().

Default implementation returns 0.

If you want to support scroll bars, override computeHorizontalScrollExtent(RecyclerView.State) in your LayoutManager.

Returns
int The horizontal extent of the scrollbar's thumb

computeHorizontalScrollOffset

added in version 22.1.0
int computeHorizontalScrollOffset ()

Compute the horizontal offset of the horizontal scrollbar's thumb within the horizontal range. This value is used to compute the length of the thumb within the scrollbar's track.

The range is expressed in arbitrary units that must be the same as the units used by computeHorizontalScrollRange() and computeHorizontalScrollExtent().

Default implementation returns 0.

If you want to support scroll bars, override computeHorizontalScrollOffset(RecyclerView.State) in your LayoutManager.

Returns
int The horizontal offset of the scrollbar's thumb

computeHorizontalScrollRange

added in version 22.1.0
int computeHorizontalScrollRange ()

Compute the horizontal range that the horizontal scrollbar represents.

The range is expressed in arbitrary units that must be the same as the units used by computeHorizontalScrollExtent() and computeHorizontalScrollOffset().

Default implementation returns 0.

If you want to support scroll bars, override computeHorizontalScrollRange(RecyclerView.State) in your LayoutManager.

Returns
int The total horizontal range represented by the vertical scrollbar

computeVerticalScrollExtent

added in version 22.1.0
int computeVerticalScrollExtent ()

Compute the vertical extent of the vertical scrollbar's thumb within the vertical range. This value is used to compute the length of the thumb within the scrollbar's track.

The range is expressed in arbitrary units that must be the same as the units used by computeVerticalScrollRange() and computeVerticalScrollOffset().

Default implementation returns 0.

If you want to support scroll bars, override computeVerticalScrollExtent(RecyclerView.State) in your LayoutManager.

Returns
int The vertical extent of the scrollbar's thumb

computeVerticalScrollOffset

added in version 22.1.0
int computeVerticalScrollOffset ()

Compute the vertical offset of the vertical scrollbar's thumb within the vertical range. This value is used to compute the length of the thumb within the scrollbar's track.

The range is expressed in arbitrary units that must be the same as the units used by computeVerticalScrollRange() and computeVerticalScrollExtent().

Default implementation returns 0.

If you want to support scroll bars, override computeVerticalScrollOffset(RecyclerView.State) in your LayoutManager.

Returns
int The vertical offset of the scrollbar's thumb

computeVerticalScrollRange

added in version 22.1.0
int computeVerticalScrollRange ()

Compute the vertical range that the vertical scrollbar represents.

The range is expressed in arbitrary units that must be the same as the units used by computeVerticalScrollExtent() and computeVerticalScrollOffset().

Default implementation returns 0.

If you want to support scroll bars, override computeVerticalScrollRange(RecyclerView.State) in your LayoutManager.

Returns
int The total vertical range represented by the vertical scrollbar

dispatchNestedFling

boolean dispatchNestedFling (float velocityX, 
                float velocityY, 
                boolean consumed)

Parameters
velocityX float

velocityY float

consumed boolean

Returns
boolean

dispatchNestedPreFling

boolean dispatchNestedPreFling (float velocityX, 
                float velocityY)

Parameters
velocityX float

velocityY float

Returns
boolean

dispatchNestedPreScroll

boolean dispatchNestedPreScroll (int dx, 
                int dy, 
                int[] consumed, 
                int[] offsetInWindow)

Parameters
dx int

dy int

consumed int

offsetInWindow int

Returns
boolean

dispatchNestedPreScroll

added in version 26.1.0
boolean dispatchNestedPreScroll (int dx, 
                int dy, 
                int[] consumed, 
                int[] offsetInWindow, 
                int type)

Dispatch one step of a nested scroll in progress before this view consumes any portion of it.

Nested pre-scroll events are to nested scroll events what touch intercept is to touch. dispatchNestedPreScroll offers an opportunity for the parent view in a nested scrolling operation to consume some or all of the scroll operation before the child view consumes it.

Parameters
dx int: Horizontal scroll distance in pixels
dy int: Vertical scroll distance in pixels
consumed int: Output. If not null, consumed[0] will contain the consumed component of dx and consumed[1] the consumed dy.
offsetInWindow int: Optional. If not null, on return this will contain the offset in local view coordinates of this view from before this operation to after it completes. View implementations may use this to adjust expected input coordinate tracking.
type int: the type of input which cause this scroll event
Returns
boolean true if the parent consumed some or all of the scroll delta

dispatchNestedScroll

added in version 26.1.0
boolean dispatchNestedScroll (int dxConsumed, 
                int dyConsumed, 
                int dxUnconsumed, 
                int dyUnconsumed, 
                int[] offsetInWindow, 
                int type)

Dispatch one step of a nested scroll in progress.

Implementations of views that support nested scrolling should call this to report info about a scroll in progress to the current nested scrolling parent. If a nested scroll is not currently in progress or nested scrolling is not enabled for this view this method does nothing.

Compatible View implementations should also call dispatchNestedPreScroll before consuming a component of the scroll event themselves.

Parameters
dxConsumed int: Horizontal distance in pixels consumed by this view during this scroll step
dyConsumed int: Vertical distance in pixels consumed by this view during this scroll step
dxUnconsumed int: Horizontal scroll distance in pixels not consumed by this view
dyUnconsumed int: Horizontal scroll distance in pixels not consumed by this view
offsetInWindow int: Optional. If not null, on return this will contain the offset in local view coordinates of this view from before this operation to after it completes. View implementations may use this to adjust expected input coordinate tracking.
type int: the type of input which cause this scroll event
Returns
boolean true if the event was dispatched, false if it could not be dispatched.

dispatchNestedScroll

boolean dispatchNestedScroll (int dxConsumed, 
                int dyConsumed, 
                int dxUnconsumed, 
                int dyUnconsumed, 
                int[] offsetInWindow)

Parameters
dxConsumed int

dyConsumed int

dxUnconsumed int

dyUnconsumed int

offsetInWindow int

Returns
boolean

draw

void draw (Canvas c)

Parameters
c Canvas

drawChild

added in version 24.1.0
boolean drawChild (Canvas canvas, 
                View child, 
                long drawingTime)

Parameters
canvas Canvas

child View

drawingTime long

Returns
boolean

findChildViewUnder

added in version 22.1.0
View findChildViewUnder (float x, 
                float y)

Find the topmost view under the given point.

Parameters
x float: Horizontal position in pixels to search
y float: Vertical position in pixels to search
Returns
View The child view under (x, y) or null if no matching child is found

findContainingItemView

added in version 24.1.0
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 RecyclerView. This returned view can be used to get the ViewHolder by calling getChildViewHolder(View).

Parameters
view View: The view that is a descendant of the RecyclerView.
Returns
View The direct child of the RecyclerView which contains the given view or null if the provided view is not a descendant of this RecyclerView.

findContainingViewHolder

added in version 24.1.0
RecyclerView.ViewHolder findContainingViewHolder (View view)

Returns the ViewHolder that contains the given view.

Parameters
view View: The view that is a descendant of the RecyclerView.
Returns
RecyclerView.ViewHolder The ViewHolder that contains the given view or null if the provided view is not a descendant of this RecyclerView.

findViewHolderForAdapterPosition

added in version 22.1.0
RecyclerView.ViewHolder findViewHolderForAdapterPosition (int position)

Return the ViewHolder for the item in the given position of the data set. Unlike findViewHolderForLayoutPosition(int) this method takes into account any pending adapter changes that may not be reflected to the layout yet. On the other hand, if notifyDataSetChanged() has been called but the new layout has not been calculated yet, this method will return null since the new positions of views are unknown until the layout is calculated.

This method checks only the children of RecyclerView. If the item at the given position is not laid out, it will not create a new one.

When the ItemAnimator is running a change animation, there might be 2 ViewHolders representing the same Item. In this case, the updated ViewHolder will be returned.

Parameters
position int: The position of the item in the data set of the adapter
Returns
RecyclerView.ViewHolder The ViewHolder at position or null if there is no such item

findViewHolderForItemId

added in version 22.1.0
RecyclerView.ViewHolder findViewHolderForItemId (long id)

Return the ViewHolder for the item with the given id. The RecyclerView must use an Adapter with stableIds to return a non-null value.

This method checks only the children of RecyclerView. If the item with the given id is not laid out, it will not create a new one. When the ItemAnimator is running a change animation, there might be 2 ViewHolders with the same id. In this case, the updated ViewHolder will be returned.

Parameters
id long: The id for the requested item
Returns
RecyclerView.ViewHolder The ViewHolder with the given id or null if there is no such item

findViewHolderForLayoutPosition

added in version 22.1.0
RecyclerView.ViewHolder findViewHolderForLayoutPosition (int position)

Return the ViewHolder for the item in the given position of the data set as of the latest layout pass.

This method checks only the children of RecyclerView. If the item at the given position is not laid out, it will not create a new one.

Note that when Adapter contents change, ViewHolder positions are not updated until the next layout calculation. If there are pending adapter updates, the return value of this method may not match your adapter contents. You can use #getAdapterPosition() to get the current adapter position of a ViewHolder.

When the ItemAnimator is running a change animation, there might be 2 ViewHolders with the same layout position representing the same Item. In this case, the updated ViewHolder will be returned.

Parameters
position int: The position of the item in the data set of the adapter
Returns
RecyclerView.ViewHolder The ViewHolder at position or null if there is no such item

findViewHolderForPosition

added in version 22.1.0
RecyclerView.ViewHolder findViewHolderForPosition (int position)

This method was deprecated in API level 22.1.0.
use findViewHolderForLayoutPosition(int) or findViewHolderForAdapterPosition(int)

Parameters
position int

Returns
RecyclerView.ViewHolder

fling

added in version 22.1.0
boolean fling (int velocityX, 
                int velocityY)

Begin a standard fling with an initial velocity along each axis in pixels per second. If the velocity given is below the system-defined minimum this method will return false and no fling will occur.

Parameters
velocityX int: Initial horizontal velocity in pixels per second
velocityY int: Initial vertical velocity in pixels per second
Returns
boolean true if the fling was started, false if the velocity was too low to fling or LayoutManager does not support scrolling in the axis fling is issued.

focusSearch

View focusSearch (View focused, 
                int direction)

Since RecyclerView is a collection ViewGroup that includes virtual children (items that are in the Adapter but not visible in the UI), it employs a more involved focus search strategy that differs from other ViewGroups.

It first does a focus search within the RecyclerView. If this search finds a View that is in the focus direction with respect to the currently focused View, RecyclerView returns that child as the next focus target. When it cannot find such child, it calls onFocusSearchFailed(View, int, Recycler, State) to layout more Views in the focus search direction. If LayoutManager adds a View that matches the focus search criteria, it will be returned as the focus search result. Otherwise, RecyclerView will call parent to handle the focus search like a regular ViewGroup.

When the direction is FOCUS_FORWARD or FOCUS_BACKWARD, a View that is not in the focus direction is still valid focus target which may not be the desired behavior if the Adapter has more children in the focus direction. To handle this case, RecyclerView converts the focus direction to an absolute direction and makes a preliminary focus search in that direction. If there are no Views to gain focus, it will call onFocusSearchFailed(View, int, Recycler, State) before running a focus search with the original (relative) direction. This allows RecyclerView to provide better candidates to the focus search while still allowing the view system to take focus from the RecyclerView and give it to a more suitable child if such child exists.

Parameters
focused View: The view that currently has focus
direction int: One of FOCUS_UP, FOCUS_DOWN, FOCUS_LEFT, FOCUS_RIGHT, FOCUS_FORWARD, FOCUS_BACKWARD or 0 for not applicable.
Returns
View A new View that can be the next focus after the focused View

generateLayoutParams

ViewGroup.LayoutParams generateLayoutParams (AttributeSet attrs)

Parameters
attrs AttributeSet

Returns
ViewGroup.LayoutParams

getAdapter

added in version 22.1.0
Adapter getAdapter ()

Retrieves the previously set adapter or null if no adapter is set.

Returns
Adapter The previously set adapter

getBaseline

int getBaseline ()

Return the offset of the RecyclerView's text baseline from the its top boundary. If the LayoutManager of this RecyclerView does not support baseline alignment, this method returns -1.

Returns
int the offset of the baseline within the RecyclerView's bounds or -1 if baseline alignment is not supported

getChildAdapterPosition

added in version 22.1.0
int getChildAdapterPosition (View child)

Return the adapter position that the given child view corresponds to.

Parameters
child View: Child View to query
Returns
int Adapter position corresponding to the given view or NO_POSITION

getChildItemId

added in version 22.1.0
long getChildItemId (View child)

Return the stable item id that the given child view corresponds to.

Parameters
child View: Child View to query
Returns
long Item id corresponding to the given view or NO_ID

getChildLayoutPosition

added in version 22.1.0
int getChildLayoutPosition (View child)

Return the adapter position of the given child view as of the latest completed layout pass.

This position may not be equal to Item's adapter position if there are pending changes in the adapter which have not been reflected to the layout yet.

Parameters
child View: Child View to query
Returns
int Adapter position of the given View as of last layout pass or NO_POSITION if the View is representing a removed item.

getChildPosition

added in version 22.1.0
int getChildPosition (View child)

This method was deprecated in API level 22.1.0.
use getChildAdapterPosition(View) or getChildLayoutPosition(View).

Parameters
child View

Returns
int

getChildViewHolder

added in version 22.1.0
RecyclerView.ViewHolder getChildViewHolder (View child)

Retrieve the RecyclerView.ViewHolder for the given child view.

Parameters
child View: Child of this RecyclerView to query for its ViewHolder
Returns
RecyclerView.ViewHolder The child view's ViewHolder

getClipToPadding

boolean getClipToPadding ()

Returns whether this RecyclerView will clip its children to its padding, and resize (but not clip) any EdgeEffect to the padded region, if padding is present.

By default, children are clipped to the padding of their parent RecyclerView. This clipping behavior is only enabled if padding is non-zero.

Returns
boolean true if this RecyclerView clips children to its padding and resizes (but doesn't clip) any EdgeEffect to the padded region, false otherwise.

getCompatAccessibilityDelegate

added in version 22.1.0
RecyclerViewAccessibilityDelegate getCompatAccessibilityDelegate ()

Returns the accessibility delegate compatibility implementation used by the RecyclerView.

Returns
RecyclerViewAccessibilityDelegate An instance of AccessibilityDelegateCompat used by RecyclerView

getDecoratedBoundsWithMargins

added in version 25.1.0
void getDecoratedBoundsWithMargins (View view, 
                Rect outBounds)

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.

getEdgeEffectFactory

added in version 27.1.0
RecyclerView.EdgeEffectFactory getEdgeEffectFactory ()

Retrieves the previously set RecyclerView.EdgeEffectFactory or the default factory if nothing was set.

Returns
RecyclerView.EdgeEffectFactory The previously set RecyclerView.EdgeEffectFactory

getItemAnimator

added in version 22.1.0
RecyclerView.ItemAnimator getItemAnimator ()

Gets the current ItemAnimator for this RecyclerView. A null return value indicates that there is no animator and that item changes will happen without any animations. By default, RecyclerView instantiates and uses an instance of DefaultItemAnimator.

Returns
RecyclerView.ItemAnimator ItemAnimator The current ItemAnimator. If null, no animations will occur when changes occur to the items in this RecyclerView.

getItemDecorationAt

added in version 26.1.0
RecyclerView.ItemDecoration getItemDecorationAt (int index)

Returns an RecyclerView.ItemDecoration previously added to this RecyclerView.

Parameters
index int: The index position of the desired ItemDecoration.
Returns
RecyclerView.ItemDecoration the ItemDecoration at index position
Throws
IndexOutOfBoundsException on invalid index

getItemDecorationCount

added in version 27.1.0
int getItemDecorationCount ()

Returns the number of RecyclerView.ItemDecoration currently added to this RecyclerView.

Returns
int number of ItemDecorations currently added added to this RecyclerView.

getLayoutManager

added in version 22.1.0
RecyclerView.LayoutManager getLayoutManager ()

Return the RecyclerView.LayoutManager currently responsible for layout policy for this RecyclerView.

Returns
RecyclerView.LayoutManager The currently bound LayoutManager

getMaxFlingVelocity

added in version 24.1.0
int getMaxFlingVelocity ()

Returns the maximum fling velocity used by this RecyclerView.

Returns
int The maximum fling velocity used by this RecyclerView.

getMinFlingVelocity

added in version 24.1.0
int getMinFlingVelocity ()

Returns the minimum velocity to start a fling.

Returns
int The minimum velocity to start a fling

getOnFlingListener

added in version 25.1.0
RecyclerView.OnFlingListener getOnFlingListener ()

Get the current RecyclerView.OnFlingListener from this RecyclerView.

Returns
RecyclerView.OnFlingListener The RecyclerView.OnFlingListener instance currently set (can be null).

getPreserveFocusAfterLayout

added in version 24.1.0
boolean getPreserveFocusAfterLayout ()

Returns true if the RecyclerView should attempt to preserve currently focused Adapter Item's focus even if the View representing the Item is replaced during a layout calculation.

By default, this value is true.

Returns
boolean True if the RecyclerView will try to preserve focused Item after a layout if it loses focus.

getRecycledViewPool

added in version 22.1.0
RecyclerView.RecycledViewPool getRecycledViewPool ()

Retrieve this RecyclerView's RecyclerView.RecycledViewPool. This method will never return null; if no pool is set for this view a new one will be created. See setRecycledViewPool for more information.

Returns
RecyclerView.RecycledViewPool The pool used to store recycled item views for reuse.

getScrollState

added in version 22.1.0
int getScrollState ()

Return the current scrolling state of the RecyclerView.

Returns
int SCROLL_STATE_IDLE, SCROLL_STATE_DRAGGING or SCROLL_STATE_SETTLING

hasFixedSize

added in version 22.1.0
boolean hasFixedSize ()

Returns
boolean true if the app has specified that changes in adapter content cannot change the size of the RecyclerView itself.

hasNestedScrollingParent

boolean hasNestedScrollingParent ()

Returns
boolean

hasNestedScrollingParent

added in version 26.1.0
boolean hasNestedScrollingParent (int type)

Returns true if this view has a nested scrolling parent for the given input type.

The presence of a nested scrolling parent indicates that this view has initiated a nested scroll and it was accepted by an ancestor view further up the view hierarchy.

Parameters
type int: the type of input which cause this scroll event
Returns
boolean whether this view has a nested scrolling parent

hasPendingAdapterUpdates

added in version 22.1.0
boolean hasPendingAdapterUpdates ()

Returns whether there are pending adapter updates which are not yet applied to the layout.

If this method returns true, it means that what user is currently seeing may not reflect them adapter contents (depending on what has changed). You may use this information to defer or cancel some operations.

This method returns true if