StackView

Adds the children of this View relevant for accessibility to the given list as output. Since some Views are not important for accessibility the added child views are not necessarily direct children of this view, rather they are the first level of descendants important for accessibility.

Adds any focusable views that are descendants of this view (possibly including this view if it is focusable itself) to views. This method adds all focusable views regardless if we are in touch mode or only views focusable in touch mode if we are in touch mode or only views that can take accessibility focus if accessibility is enabled depending on the focusable mode parameter.

Adds any keyboard navigation cluster roots that are descendants of this view (possibly including this view if it is a cluster root itself) to views.

Returns whether this ViewGroup's drawable states also include its children's drawable states. This is used, for example, to make a group appear to be focused when its child EditText or button is focused.

Add any touchable views that are descendants of this view (possibly including this view if it is touchable itself) to views.

Adds a child view with this ViewGroup's default layout parameters and the specified width and height.

Note: do not invoke this method from draw(android.graphics.Canvas), onDraw(android.graphics.Canvas), dispatchDraw(android.graphics.Canvas) or any related method.

Adds a view during layout. This is useful if in your onLayout() method, you need to add more views (as does the list view for example). If index is negative, it means put it at the end of the list.

Adds a view during layout. This is useful if in your onLayout() method, you need to add more views (as does the list view for example). If index is negative, it means put it at the end of the list.

Subclasses should override this method to set layout animation parameters on the supplied child.

Attaches a view to this view group. Attaching a view assigns this group as the parent, sets the layout parameters and puts the view in the list of children so that it can be retrieved by calling getChildAt(int).

This method is intended to be lightweight and makes no assumptions about whether the parent or child should be redrawn. Proper use of this method will include also making any appropriate #requestLayout() or invalidate() calls. For example, callers can post a Runnable which performs a #requestLayout() on the next frame, after all detach/attach calls are finished, causing layout to be run prior to redrawing the view hierarchy.

This method should be called only for views which were detached from their parent.

Change the z order of the child so it's on top of all other children. This ordering change may affect layout, if this container uses an order-dependent layout scheme (e.g., LinearLayout). Prior to android.os.Build.VERSION_CODES#KITKAT this method should be followed by calls to requestLayout() and View.invalidate() on this parent to force the parent to redraw with the new child ordering.

If addStatesFromChildren is true, refreshes this group's drawable state (to include the states from its children).

Called when a child view has changed whether or not it is tracking transient state.

Prevents the specified child to be laid out during the next layout pass.

Called when a child of this parent is giving up focus

Removes any pending animations for views that have been removed. Call this if you don't want animations for exiting views to stack up.

Called when this view wants to give up focus. If focus is cleared onFocusChanged(boolean,int,android.graphics.Rect) is called.

Note: When not in touch-mode, the framework will try to give focus to the first focusable View from the top after focus is cleared. Hence, if this View is the first from the top that can take focus, then all callbacks related to clearing focus will be invoked after which the framework will give focus to this view.

Detaches all views from the parent. Detaching a view should be followed either by a call to attachViewToParent(android.view.View,int,android.view.ViewGroup.LayoutParams) or a call to removeDetachedView(android.view.View,boolean). Detachment should only be temporary; reattachment or removal should happen within the same drawing cycle as detachment. When a view is detached, its parent is null and cannot be retrieved by a call to getChildAt(int).

Detaches a view from its parent. Detaching a view should be followed either by a call to attachViewToParent(android.view.View,int,android.view.ViewGroup.LayoutParams) or a call to removeDetachedView(android.view.View,boolean). Detachment should only be temporary; reattachment or removal should happen within the same drawing cycle as detachment. When a view is detached, its parent is null and cannot be retrieved by a call to getChildAt(int).

Detaches a view from its parent. Detaching a view should be followed either by a call to attachViewToParent(android.view.View,int,android.view.ViewGroup.LayoutParams) or a call to removeDetachedView(android.view.View,boolean). Detachment should only be temporary; reattachment or removal should happen within the same drawing cycle as detachment. When a view is detached, its parent is null and cannot be retrieved by a call to getChildAt(int).

Detaches a range of views from their parents. Detaching a view should be followed either by a call to attachViewToParent(android.view.View,int,android.view.ViewGroup.LayoutParams) or a call to removeDetachedView(android.view.View,boolean). Detachment should only be temporary; reattachment or removal should happen within the same drawing cycle as detachment. When a view is detached, its parent is null and cannot be retrieved by a call to getChildAt(int).

Request to apply the given window insets to this view or another view in its subtree.

This method should be called by clients wishing to apply insets corresponding to areas obscured by window decorations or overlays. This can include the status and navigation bars, action bars, input methods and more. New inset categories may be added in the future. The method returns the insets provided minus any that were applied by this view or its children.

Clients wishing to provide custom behavior should override the onApplyWindowInsets(android.view.WindowInsets) method or alternatively provide a OnApplyWindowInsetsListener via the setOnApplyWindowInsetsListener method.

This method replaces the older fitSystemWindows method.

Pass a captured pointer event down to the focused view.

Dispatch a notification about a resource configuration change down the view hierarchy. ViewGroups should override to route to their children.

Dispatch to collect the ViewTranslationRequests for translation purpose by traversing the hierarchy when the app requests ui translation. Typically, this method should only be overridden by subclasses that provide a view hierarchy (such as ViewGroup). Other classes should override View.onCreateViewTranslationRequest for normal view or override View.onVirtualViewTranslationResponses for view contains virtual children. When requested to start the ui translation, the system will call this method to traverse the view hierarchy to collect ViewTranslationRequests and create a android.view.translation.Translator to translate the requests. All the ViewTranslationRequests must be added when the traversal is done.

The default implementation calls View.onCreateViewTranslationRequest for normal view or calls View.onVirtualViewTranslationResponses for view contains virtual children to build ViewTranslationRequest if the view should be translated. The view is marked as having transient state so that recycling of views doesn't prevent the system from attaching the response to it. Therefore, if overriding this method, you should set or reset the transient state.

Dispatch a hint about whether this view is displayed. For instance, when a View moves out of the screen, it might receives a display hint indicating the view is not displayed. Applications should not rely on this hint as there is no guarantee that they will receive one.

Detects if this View is enabled and has a drag event listener. If both are true, then it calls the drag event listener with the android.view.DragEvent it received. If the drag event listener returns true, then dispatchDragEvent() returns true.

For all other cases, the method calls the onDragEvent() drag event handler method and returns its result.

This ensures that a drag event is always consumed, even if the View does not have a drag event listener. However, if the View has a listener and the listener returns true, then onDragEvent() is not called.

Called by draw to draw the child views. This may be overridden by derived classes to gain control just before its children are drawn (but after its own view has been drawn).

Dispatches drawable hotspot changes to child views that meet at least one of the following criteria:

• Returns false from both View.isClickable() and View.isLongClickable()
• Requests duplication of parent state via View.setDuplicateParentStateEnabled(boolean)

Perform dispatching of a saveHierarchyState(android.util.SparseArray) freeze()} to only this view, not to its children. For use when overriding dispatchSaveInstanceState(android.util.SparseArray) dispatchFreeze()} to allow subclasses to freeze their own state but not the state of their children.

Dispatch a generic motion event to the currently focused view.

Do not call this method directly. Call dispatchGenericMotionEvent(android.view.MotionEvent) instead.

Dispatch a generic motion event to the view under the first pointer.

Do not call this method directly. Call dispatchGenericMotionEvent(android.view.MotionEvent) instead.

Dispatch a hover event.

Do not call this method directly. Call dispatchGenericMotionEvent(android.view.MotionEvent) instead.

Dispatch a key event to the next view on the focus path. This path runs from the top of the view tree down to the currently focused view. If this view has focus, it will dispatch to itself. Otherwise it will dispatch the next node down the focus path. This method also fires any key listeners.

Dispatch a key event before it is processed by any input method associated with the view hierarchy. This can be used to intercept key events in special situations before the IME consumes them; a typical example would be handling the BACK key to update the application's UI instead of allowing the IME to see it and close itself.

Dispatches a key shortcut event.

Dispatches creation of a ViewStructures for autofill purposes down the hierarchy, when an Assist structure is being created as part of an autofill request.

The default implementation does the following:

• Sets the AutofillId in the structure.
• Calls onProvideAutofillStructure(android.view.ViewStructure,int).
• Calls onProvideAutofillVirtualStructure(android.view.ViewStructure,int).

Typically, this method should only be overridden by subclasses that provide a view hierarchy (such as ViewGroup) - other classes should override onProvideAutofillStructure(android.view.ViewStructure,int) or onProvideAutofillVirtualStructure(android.view.ViewStructure,int) instead.

When overridden, it must:

• Either call super.dispatchProvideAutofillStructure(structure, flags) or explicitly set the AutofillId in the structure (for example, by calling structure.setAutofillId(getAutofillId())).
• Decide how to handle the AUTOFILL_FLAG_INCLUDE_NOT_IMPORTANT_VIEWS flag - when set, all views in the structure should be considered important for autofill, regardless of what isImportantForAutofill() returns. We encourage you to respect this flag to provide a better user experience - this flag is typically used when an user explicitly requested autofill. If the flag is not set, then only views marked as important for autofill should be included in the structure - skipping non-important views optimizes the overall autofill performance.

This implementation adds in all child views of the view group, in addition to calling the default View implementation.

Dispatch creation of ViewStructure down the hierarchy. This implementation adds in all child views of the view group, in addition to calling the default View implementation.

Handle the scroll capture search request by checking this view if applicable, then to each child view.

Dispatch setActivated to all of this View's children.

Dispatch setPressed to all of this View's children.

Dispatch setSelected to all of this View's children.

Dispatch callbacks to setOnSystemUiVisibilityChangeListener down the view hierarchy.

Perform dispatching of a restoreHierarchyState(android.util.SparseArray) to only this view, not to its children. For use when overriding dispatchRestoreInstanceState(android.util.SparseArray) to allow subclasses to thaw their own state but not the state of their children.

Pass the touch screen motion event down to the target view, or this view if it is the target.

Pass a trackball motion event down to the focused view.

This method is the last chance for the focused view and its ancestors to respond to an arrow key. This is called when the focused view did not consume the key internally, nor could the view system find a new view in the requested direction to give focus to.

Dispatch a view visibility change down the view hierarchy. ViewGroups should override to route to their children.

Called when the window containing this view gains or loses window focus. ViewGroups should override to route to their children.

Dispatches WindowInsetsAnimation.Callback.onEnd(WindowInsetsAnimation) when Window Insets animation ends.

Dispatches WindowInsetsAnimation.Callback.onPrepare(WindowInsetsAnimation) when Window Insets animation is being prepared.

Dispatches WindowInsetsAnimation.Callback.onProgress(WindowInsets, List) when Window Insets animation makes progress.

Dispatches WindowInsetsAnimation.Callback.onStart(WindowInsetsAnimation, Bounds) when Window Insets animation is started.

Dispatch callbacks to onWindowSystemUiVisibilityChanged(int) down the view hierarchy.

Dispatch a window visibility change down the view hierarchy. ViewGroups should override to route to their children.

Draw one child of this View Group. This method is responsible for getting the canvas in the right state. This includes clipping, translating so that the child's scrolled origin is at 0, 0, and applying any animation transformations.

This function is called whenever the state of the view changes in such a way that it impacts the state of drawables being shown.

If the View has a StateListAnimator, it will also be called to run necessary state change animations.

Be sure to call through to the superclass when overriding this function.
If you override this method you must call through to the superclass implementation.

This method should always be called following an earlier call to startViewTransition(android.view.View). The given View is finally removed from its parent and will no longer be displayed. Note that this method does not perform the functionality of removing a view from its parent; it just discontinues the display of a View that has previously been removed.

Find the view in the hierarchy rooted at this view that currently has focus.

Walk up the View hierarchy to find the nearest OnBackInvokedDispatcher.

Finds the Views that contain given text. The containment is case insensitive. The search is performed by either the text that the View renders or the content description that describes the view for accessibility purposes and the view does not render or both. Clients can specify how the search is to be performed via passing the FIND_VIEWS_WITH_TEXT and FIND_VIEWS_WITH_CONTENT_DESCRIPTION flags.

Find the nearest view in the specified direction that wants to take focus.

Tells the parent that a new focusable view has become available. This is to handle transitions from the case where there are no focusable views to the case where the first focusable view appears.

This is used by the ViewRoot to perform an optimization when the view hierarchy contains one or several SurfaceView. SurfaceView is always considered transparent, but its children are not, therefore all View objects remove themselves from the global transparent region (passed as a parameter to this function).

Returns a set of default layout parameters. These parameters are requested when the View passed to addView(android.view.View) has no layout parameters already set. If null is returned, an exception is thrown from addView.

Returns a new set of layout parameters based on the supplied attributes set.

Returns a safe set of layout parameters based on the supplied layout params. When a ViewGroup is passed a View whose layout params do not pass the test of checkLayoutParams(android.view.ViewGroup.LayoutParams), this method is invoked. This method should return a new set of layout params suitable for this ViewGroup, possibly by copying the appropriate attributes from the specified set of layout params.

Returns the view at the specified position in the group.

Returns the number of children in the group.

Converts drawing order position to container position.

Children are not necessarily drawn in the order in which they appear in the container. ViewGroups can enable a custom ordering via setChildrenDrawingOrderEnabled(boolean). This method returns the container position of a child that appears in the given position in the current drawing order.

Converts drawing order position to container position. Override this if you want to change the drawing order of children. By default, it returns drawingPosition.

NOTE: In order for this method to be called, you must enable child ordering first by calling setChildrenDrawingOrderEnabled(boolean).

Does the hard part of measureChildren: figuring out the MeasureSpec to pass to a particular child. This method figures out the right MeasureSpec for one dimension (height or width) of one child view. The goal is to combine information from our MeasureSpec with the LayoutParams of the child to get the best possible results. For example, if the this view knows its size (because its MeasureSpec has a mode of EXACTLY), and the child has indicated in its LayoutParams that it wants to be the same size as the parent, the parent should ask the child to layout given an exact size.

Sets t to be the static transformation of the child, if set, returning a boolean to indicate whether a static transform was set. The default implementation simply returns false; subclasses may override this method for different behavior. setStaticTransformationsEnabled(boolean) must be set to true for this method to be called.

Compute the visible part of a rectangular region defined in terms of a child view's coordinates.

Returns the clipped visible part of the rectangle r, defined in the child's local coordinate system. r is modified by this method to contain the result, expressed in the global (root) coordinate system.

The resulting rectangle is always axis aligned. If a rotation is applied to a node in the View hierarchy, the result is the axis-aligned bounding box of the visible rectangle.

Returns whether this group's children are clipped to their bounds before drawing. The default value is true.

Returns whether this ViewGroup 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 Viewgroup. This clipping behavior is only enabled if padding is non-zero.

Gets the descendant focusability of this view group. The descendant focusability defines the relationship between this view group and its descendants when looking for a view to take focus in requestFocus(int,android.graphics.Rect).

Returns the focused child of this view, if any. The child may have focus or contain focus.

Returns the layout animation controller used to animate the group's children.

Returns the animation listener to which layout animation events are sent.

Returns the basis of alignment during layout operations on this ViewGroup: either LAYOUT_MODE_CLIP_BOUNDS or LAYOUT_MODE_OPTICAL_BOUNDS.

If no layoutMode was explicitly set, either programmatically or in an XML resource, the method returns the layoutMode of the view's parent ViewGroup if such a parent exists, otherwise the method returns a default value of LAYOUT_MODE_CLIP_BOUNDS.

Gets the LayoutTransition object for this ViewGroup. If the LayoutTransition object is not null, changes in layout which occur because of children being added to or removed from the ViewGroup will be animated according to the animations defined in that LayoutTransition object. By default, the transition object is null (so layout changes are not animated).

Return the current axes of nested scrolling for this ViewGroup.

A ViewGroup returning something other than SCROLL_AXIS_NONE is currently acting as a nested scrolling parent for one or more descendant views in the hierarchy.

Returns the ViewGroupOverlay for this view group, creating it if it does not yet exist. In addition to ViewOverlay's support for drawables, ViewGroupOverlay allows views to be added to the overlay. These views, like overlay drawables, are visual-only; they do not receive input events and should not be used as anything other than a temporary representation of a view in a parent container, such as might be used by an animation effect.

Note: Overlays do not currently work correctly with SurfaceView or TextureView; contents in overlays for these types of views may not display correctly.

Returns an integer indicating what types of drawing caches are kept in memory.

Check whether this ViewGroup should ignore focus requests for itself and its children.

Returns true if this view has or contains focus

Indicates whether the view is currently tracking transient state that the app should not need to concern itself with saving and restoring, but that the framework should take special note to preserve when possible.

A view with transient state cannot be trivially rebound from an external data source, such as an adapter binding item views in a list. This may be because the view is performing an animation, tracking user selection of content, or similar.

Returns the position in the group of the specified child view.

Don't call or override this method. It is used for the implementation of the view hierarchy.

Don't call or override this method. It is used for the implementation of the view hierarchy. This implementation returns null if this ViewGroup does not have a parent, if this ViewGroup is already fully invalidated or if the dirty rectangle does not intersect with this ViewGroup's bounds.

Indicates whether this ViewGroup will always try to draw its children using their drawing cache. By default this property is enabled.

Indicates whether the children's drawing cache is used during a layout animation. By default, the drawing cache is enabled but this will prevent nested layout animations from working. To nest animations, you must disable the cache.

Indicates whether the ViewGroup is drawing its children in the order defined by getChildDrawingOrder(int,int).

Indicates whether the ViewGroup is currently drawing its children using their drawing cache.

Returns whether layout calls on this container are currently being suppressed, due to an earlier call to suppressLayout(boolean).

Returns true if MotionEvents dispatched to this ViewGroup can be split to multiple children.

Returns true if this ViewGroup should be considered as a single entity for removal when executing an Activity transition. If this is false, child elements will move individually during the transition.

Call Drawable.jumpToCurrentState() on all Drawable objects associated with this view.

Also calls StateListAnimator.jumpToCurrentState() if there is a StateListAnimator attached to this view.
If you override this method you must call through to the superclass implementation.

Assign a size and position to a view and all of its descendants

This is the second phase of the layout mechanism. (The first is measuring). In this phase, each parent calls layout on all of its children to position them. This is typically done using the child measurements that were stored in the measure pass().

Derived classes should not override this method. Derived classes with children should override onLayout. In that method, they should call layout on each of their children.

Ask one of the children of this view to measure itself, taking into account both the MeasureSpec requirements for this view and its padding. The heavy lifting is done in getChildMeasureSpec.

Ask one of the children of this view to measure itself, taking into account both the MeasureSpec requirements for this view and its padding and margins. The child must have MarginLayoutParams The heavy lifting is done in getChildMeasureSpec.

Ask all of the children of this view to measure themselves, taking into account both the MeasureSpec requirements for this view and its padding. We skip children that are in the GONE state The heavy lifting is done in getChildMeasureSpec.

Notifies a view parent that the accessibility state of one of its descendants has changed and that the structure of the subtree is different.

Offset a rectangle that is in a descendant's coordinate space into our coordinate space.

Offset a rectangle that is in our coordinate space into an ancestor's coordinate space.

This is called when the view is attached to a window. At this point it has a Surface and will start drawing. Note that this function is guaranteed to be called before onDraw(android.graphics.Canvas), however it may be called any time before the first onDraw -- including before or after onMeasure(int,int).
If you override this method you must call through to the superclass implementation.

Generate the new android.graphics.drawable.Drawable state for this view. This is called by the view system when the cached Drawable state is determined to be invalid. To retrieve the current state, you should use getDrawableState.

The target View has been invalidated, or has had a drawing property changed that requires the hierarchy to re-render. This method is called by the View hierarchy to signal ancestors that a View either needs to re-record its drawing commands, or drawing properties have changed. This is how Views schedule a drawing traversal. This signal is generally only dispatched for attached Views, since only they need to draw. If you override this method you must call through to the superclass implementation.

Implement this method to intercept hover events before they are handled by child views.

This method is called before dispatching a hover event to a child of the view group or to the view group's own onHoverEvent to allow the view group a chance to intercept the hover event. This method can also be used to watch all pointer motions that occur within the bounds of the view group even when the pointer is hovering over a child of the view group rather than over the view group itself.

The view group can prevent its children from receiving hover events by implementing this method and returning true to indicate that it would like to intercept hover events. The view group must continuously return true from onInterceptHoverEvent for as long as it wishes to continue intercepting hover events from its children.

Interception preserves the invariant that at most one view can be hovered at a time by transferring hover focus from the currently hovered child to the view group or vice-versa as needed.

If this method returns true and a child is already hovered, then the child view will first receive a hover exit event and then the view group itself will receive a hover enter event in onHoverEvent. Likewise, if this method had previously returned true to intercept hover events and instead returns false while the pointer is hovering within the bounds of one of a child, then the view group will first receive a hover exit event in onHoverEvent and then the hovered child will receive a hover enter event.

The default implementation handles mouse hover on the scroll bars.

Implement this method to intercept all touch screen motion events. This allows you to watch events as they are dispatched to your children, and take ownership of the current gesture at any point.

Using this function takes some care, as it has a fairly complicated interaction with View.onTouchEvent(MotionEvent), and using it requires implementing that method as well as this one in the correct way. Events will be received in the following order:

1. You will receive the down event here.
2. The down event will be handled either by a child of this view group, or given to your own onTouchEvent() method to handle; this means you should implement onTouchEvent() to return true, so you will continue to see the rest of the gesture (instead of looking for a parent view to handle it). Also, by returning true from onTouchEvent(), you will not receive any following events in onInterceptTouchEvent() and all touch processing must happen in onTouchEvent() like normal.
3. For as long as you return false from this function, each following event (up to and including the final up) will be delivered first here and then to the target's onTouchEvent().
4. If you return true from here, you will not receive any following events: the target view will receive the same event but with the action MotionEvent.ACTION_CANCEL, and all further events will be delivered to your onTouchEvent() method and no longer appear here.

Request a fling from a nested scroll.

This method signifies that a nested scrolling child has detected suitable conditions for a fling. Generally this means that a touch scroll has ended with a velocity in the direction of scrolling that meets or exceeds the minimum fling velocity along a scrollable axis.

If a nested scrolling child view would normally fling but it is at the edge of its own content, it can use this method to delegate the fling to its nested scrolling parent instead. The parent may optionally consume the fling or observe a child fling.

React to a nested fling before the target view consumes it.

This method siginfies that a nested scrolling child has detected a fling with the given velocity along each axis. Generally this means that a touch scroll has ended with a velocity in the direction of scrolling that meets or exceeds the minimum fling velocity along a scrollable axis.

If a nested scrolling parent is consuming motion as part of a pre-scroll, it may be appropriate for it to also consume the pre-fling to complete that same motion. By returning true from this method, the parent indicates that the child should not fling its own internal content as well.

React to an accessibility action delegated by a target descendant view before the target processes it.

This method may be called by a target descendant view if the target wishes to give a view in its parent chain a chance to react to the event before normal processing occurs. Most commonly this will be a scroll event such as android.view.accessibility.AccessibilityNodeInfo#ACTION_SCROLL_FORWARD. A ViewParent that supports acting as a nested scrolling parent should override this method and act accordingly to implement scrolling via accesibility systems.

Subclasses should always call super.onNestedPrePerformAccessibilityAction

React to a nested scroll in progress before the target view consumes a portion of the scroll.

When working with nested scrolling often the parent view may want an opportunity to consume the scroll before the nested scrolling child does. An example of this is a drawer that contains a scrollable list. The user will want to be able to scroll the list fully into view before the list itself begins scrolling.

onNestedPreScroll is called when a nested scrolling child invokes View.dispatchNestedPreScroll(int, int, int[], int[]). The implementation should report how any pixels of the scroll reported by dx, dy were consumed in the consumed array. Index 0 corresponds to dx and index 1 corresponds to dy. This parameter will never be null. Initial values for consumed[0] and consumed[1] will always be 0.

React to a nested scroll in progress.

This method will be called when the ViewParent's current nested scrolling child view dispatches a nested scroll event. To receive calls to this method the ViewParent must have previously returned true for a call to onStartNestedScroll(android.view.View,android.view.View,int).

Both the consumed and unconsumed portions of the scroll distance are reported to the ViewParent. An implementation may choose to use the consumed portion to match or chase scroll position of multiple child elements, for example. The unconsumed portion may be used to allow continuous dragging of multiple scrolling or draggable elements, such as scrolling a list within a vertical drawer where the drawer begins dragging once the edge of inner scrolling content is reached.

React to the successful claiming of a nested scroll operation.

This method will be called after onStartNestedScroll returns true. It offers an opportunity for the view and its superclasses to perform initial configuration for the nested scroll. Implementations of this method should always call their superclass's implementation of this method if one is present.

Look for a descendant to call android.view.View#requestFocus on. Called by ViewGroup.requestFocus(int, android.graphics.Rect) when it wants to request focus within its children. Override this to customize how your ViewGroup requests focus within its children.

Called when a child has requested sending an AccessibilityEvent and gives an opportunity to its parent to augment the event.

If an android.view.View.AccessibilityDelegate has been specified via calling android.view.View#setAccessibilityDelegate(android.view.View.AccessibilityDelegate) its android.view.View.AccessibilityDelegate#onRequestSendAccessibilityEvent(ViewGroup, View, AccessibilityEvent) is responsible for handling this call.

Resolve the pointer icon that should be used for specified pointer in the motion event. The default implementation will resolve the pointer icon to one set using setPointerIcon(android.view.PointerIcon) for mouse devices. Subclasses may override this to customize the icon for the given pointer. For example, to always show the PointerIcon.TYPE_HANDWRITING icon for a stylus pointer, the event can be resolved in the following way:

@Override
  public PointerIcon onResolvePointerIcon(MotionEvent event, int pointerIndex) {
      final int toolType = event.getToolType(pointerIndex);
      if (!event.isFromSource(InputDevice.SOURCE_MOUSE)
              && event.isFromSource(InputDevice.SOURCE_STYLUS)
              && (toolType == MotionEvent.TOOL_TYPE_STYLUS
                      || toolType == MotionEvent.TOOL_TYPE_ERASER)) {
          // Show this pointer icon only if this pointer is a stylus.
          return PointerIcon.getSystemIcon(mContext, PointerIcon.TYPE_HANDWRITING);
      }
      // Use the default logic for determining the pointer icon for other non-stylus pointers,
      // like for the mouse cursor.
      return super.onResolvePointerIcon(event, pointerIndex);
  }
  

React to a descendant view initiating a nestable scroll operation, claiming the nested scroll operation if appropriate.

This method will be called in response to a descendant view invoking View.startNestedScroll(int). Each parent up the view hierarchy will be given an opportunity to respond and claim the nested scrolling operation by returning true.

This method may be overridden by ViewParent implementations to indicate when the view is willing to support a nested scrolling operation that is about to begin. If it returns true, this ViewParent will become the target view's nested scrolling parent for the duration of the scroll operation in progress. When the nested scroll is finished this ViewParent will receive a call to onStopNestedScroll(android.view.View).

React to a nested scroll operation ending.

Perform cleanup after a nested scrolling operation. This method will be called when a nested scroll stops, for example when a nested touch scroll ends with a MotionEvent.ACTION_UP or MotionEvent.ACTION_CANCEL event. Implementations of this method should always call their superclass's implementation of this method if one is present.

The default implementation of onStopNestedScroll calls stopNestedScroll() to halt any recursive nested scrolling in progress.

Called when a new child is added to this ViewGroup. Overrides should always call super.onViewAdded.

Called when a child view is removed from this ViewGroup. Overrides should always call super.onViewRemoved.

You can set the preferred frame rate for a ViewGroup and its children using a positive number or by specifying the preferred frame rate category using constants, including REQUESTED_FRAME_RATE_CATEGORY_NO_PREFERENCE, REQUESTED_FRAME_RATE_CATEGORY_LOW, REQUESTED_FRAME_RATE_CATEGORY_NORMAL, REQUESTED_FRAME_RATE_CATEGORY_HIGH. Keep in mind that the preferred frame rate affects the frame rate for the next frame, so use this method carefully. It's important to note that the preference is valid as long as the ViewGroup or any of its children is invalidated. To undo the frame rate propagation, call the API with REQUESTED_FRAME_RATE_CATEGORY_DEFAULT.

Tell view hierarchy that the global view attributes need to be re-evaluated.

Called by a ViewGroup subclass to remove child views from itself, when it must first know its size on screen before it can calculate how many child views it will render. An example is a Gallery or a ListView, which may "have" 50 children, but actually only render the number of children that can currently fit inside the object on screen. Do not call this method unless you are extending ViewGroup and understand the view measuring and layout pipeline.

Note: do not invoke this method from draw(android.graphics.Canvas), onDraw(android.graphics.Canvas), dispatchDraw(android.graphics.Canvas) or any related method.

Finishes the removal of a detached view. This method will dispatch the detached from window event and notify the hierarchy change listener.

This method is intended to be lightweight and makes no assumptions about whether the parent or child should be redrawn. Proper use of this method will include also making any appropriate #requestLayout() or invalidate() calls. For example, callers can post a Runnable which performs a #requestLayout() on the next frame, after all detach/remove calls are finished, causing layout to be run prior to redrawing the view hierarchy.

Removes a view during layout. This is useful if in your onLayout() method, you need to remove more views.

Note: do not invoke this method from draw(android.graphics.Canvas), onDraw(android.graphics.Canvas), dispatchDraw(android.graphics.Canvas) or any related method.

Removes the specified range of views from the group.

Note: do not invoke this method from draw(android.graphics.Canvas), onDraw(android.graphics.Canvas), dispatchDraw(android.graphics.Canvas) or any related method.

Removes a range of views during layout. This is useful if in your onLayout() method, you need to remove more views.

Note: do not invoke this method from draw(android.graphics.Canvas), onDraw(android.graphics.Canvas), dispatchDraw(android.graphics.Canvas) or any related method.

Called when a child of this parent wants focus

Called when a child of this group wants a particular rectangle to be positioned onto the screen. ViewGroups overriding this can trust that:

• child will be a direct child of this group
• rectangle will be in the child's content coordinates

ViewGroups overriding this should uphold the contract:

• nothing will change if the rectangle is already visible
• the view port will be scrolled only just enough to make the rectangle visible

Called when a child does not want this parent and its ancestors to intercept touch events with ViewGroup.onInterceptTouchEvent(MotionEvent).

This parent should pass this call onto its parents. This parent must obey this request for the duration of the touch (that is, only clear the flag after this parent has received an up or a cancel.

Call this to try to give focus to a specific view or to one of its descendants and give it hints about the direction and a specific rectangle that the focus is coming from. The rectangle can help give larger views a finer grained hint about where focus is coming from, and therefore, where to show selection, or forward focus change internally. A view will not actually take focus if it is not focusable (isFocusable returns false), or if it is focusable and it is not focusable in touch mode (isFocusableInTouchMode) while the device is in touch mode. A View will not take focus if it is not visible. A View will not take focus if one of its parents has android.view.ViewGroup#getDescendantFocusability() equal to ViewGroup.FOCUS_BLOCK_DESCENDANTS. See also focusSearch(int), which is what you call to say that you have focus, and you want your parent to look for the next one. You may wish to override this method if your custom View has an internal View that it wishes to forward the request to. Looks for a view to give focus to respecting the setting specified by getDescendantFocusability(). Uses onRequestFocusInDescendants(int,android.graphics.Rect) to find focus within the children of this group when appropriate.

Called by a child to request from its parent to send an AccessibilityEvent. The child has already populated a record for itself in the event and is delegating to its parent to send the event. The parent can optionally add a record for itself.

Note: An accessibility event is fired by an individual view which populates the event with a record for its state and requests from its parent to perform the sending. The parent can optionally add a record for itself before dispatching the request to its parent. A parent can also choose not to respect the request for sending the event. The accessibility event is sent by the topmost view in the view tree.

Called when a child wants the view hierarchy to gather and report transparent regions to the window compositor. Views that "punch" holes in the view hierarchy, such as SurfaceView can use this API to improve performance of the system. When no such a view is present in the hierarchy, this optimization in unnecessary and might slightly reduce the view hierarchy performance.

Gives focus to the default-focus view in the view hierarchy that has this view as a root. If the default-focus view cannot be found, falls back to calling requestFocus(int).

Schedules the layout animation to be played after the next layout pass of this view group. This can be used to restart the layout animation when the content of the view group changes or when the activity is paused and resumed.

Sets whether this ViewGroup's drawable states also include its children's drawable states. This is used, for example, to make a group appear to be focused when its child EditText or button is focused.

Indicates whether this ViewGroup will always try to draw its children using their drawing cache. This property can be set to true when the cache rendering is slightly different from the children's normal rendering. Renderings can be different, for instance, when the cache's quality is set to low. When this property is disabled, the ViewGroup will use the drawing cache of its children only when asked to. It's usually the task of subclasses to tell ViewGroup when to start using the drawing cache and when to stop using it.

Enables or disables the children's drawing cache during a layout animation. By default, the drawing cache is enabled but this will prevent nested layout animations from working. To nest animations, you must disable the cache.

Enables or disables the drawing cache for each child of this view group.

Tells the ViewGroup whether to draw its children in the order defined by the method getChildDrawingOrder(int,int).

Note that Z reordering, done by dispatchDraw(android.graphics.Canvas), will override custom child ordering done via this method.

Tells the ViewGroup to draw its children using their drawing cache. This property is ignored when isAlwaysDrawnWithCacheEnabled() is true. A child's drawing cache will be used only if it has been enabled. Subclasses should call this method to start and stop using the drawing cache when they perform performance sensitive operations, like scrolling or animating.

By default, children are clipped to their bounds before drawing. This allows view groups to override this behavior for animations, etc.

Sets whether this ViewGroup 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 ViewGroup. This clipping behavior is only enabled if padding is non-zero.

Set the descendant focusability of this view group. This defines the relationship between this view group and its descendants when looking for a view to take focus in requestFocus(int,android.graphics.Rect).

Sets the layout animation controller used to animate the group's children after the first layout.

Specifies the animation listener to which layout animation events must be sent. Only android.view.animation.Animation.AnimationListener#onAnimationStart(Animation) and android.view.animation.Animation.AnimationListener#onAnimationEnd(Animation) are invoked.

Sets the basis of alignment during the layout of this ViewGroup. Valid values are either LAYOUT_MODE_CLIP_BOUNDS or LAYOUT_MODE_OPTICAL_BOUNDS.

Sets the LayoutTransition object for this ViewGroup. If the LayoutTransition object is not null, changes in layout which occur because of children being added to or removed from the ViewGroup will be animated according to the animations defined in that LayoutTransition object. By default, the transition object is null (so layout changes are not animated).

Replacing a non-null transition will cause that previous transition to be canceled, if it is currently running, to restore this container to its correct post-transition state.

Enable or disable the splitting of MotionEvents to multiple children during touch event dispatch. This behavior is enabled by default for applications that target an SDK version of Build.VERSION_CODES.HONEYCOMB or newer.

When this option is enabled MotionEvents may be split and dispatched to different child views depending on where each pointer initially went down. This allows for user interactions such as scrolling two panes of content independently, chording of buttons, and performing independent gestures on different pieces of content.

Register a callback to be invoked when a child is added to or removed from this view.

Indicates what types of drawing caches should be kept in memory after they have been created.

You can set the preferred frame rate for a ViewGroup using a positive number or by specifying the preferred frame rate category using constants, including REQUESTED_FRAME_RATE_CATEGORY_NO_PREFERENCE, REQUESTED_FRAME_RATE_CATEGORY_LOW, REQUESTED_FRAME_RATE_CATEGORY_NORMAL, REQUESTED_FRAME_RATE_CATEGORY_HIGH. Keep in mind that the preferred frame rate affects the frame rate for the next frame, so use this method carefully. It's important to note that the preference is valid as long as the ViewGroup is invalidated. Please also be aware that the requested frame rate will not propagate to child views.

When this property is set to true, this ViewGroup supports static transformations on children; this causes getChildStaticTransformation(android.view.View,android.view.animation.Transformation) to be invoked when a child is drawn. Any subclass overriding getChildStaticTransformation(android.view.View,android.view.animation.Transformation) should set this property to true.

Set whether this ViewGroup should ignore focus requests for itself and its children. If this option is enabled and the ViewGroup or a descendant currently has focus, focus will proceed forward.

Changes whether or not this ViewGroup should be treated as a single entity during Activity Transitions.

Sets a WindowInsetsAnimation.Callback to be notified about animations of windows that cause insets.

The callback's dispatch mode will affect whether animation callbacks are dispatched to the children of this view.

Return true if the pressed state should be delayed for children or descendants of this ViewGroup. Generally, this should be done for containers that can scroll, such as a List. This prevents the pressed state from appearing when the user is actually trying to scroll the content. The default implementation returns true for compatibility reasons. Subclasses that do not scroll should generally override this method and return false.

Shows the context menu for the specified view or its ancestors.

In most cases, a subclass does not need to override this. However, if the subclass is added directly to the window manager (for example, ViewManager.addView(View, android.view.ViewGroup.LayoutParams)) then it should override this and show the context menu.

Shows the context menu for the specified view or its ancestors anchored to the specified view-relative coordinate.

In most cases, a subclass does not need to override this. However, if the subclass is added directly to the window manager (for example, ViewManager.addView(View, android.view.ViewGroup.LayoutParams)) then it should override this and show the context menu.

If a subclass overrides this method it should also override showContextMenuForChild(android.view.View).

Start an action mode for the specified view with the default type ActionMode.TYPE_PRIMARY.

In most cases, a subclass does not need to override this. However, if the subclass is added directly to the window manager (for example, ViewManager.addView(View, android.view.ViewGroup.LayoutParams)) then it should override this and start the action mode.

Start an action mode of a specific type for the specified view.

In most cases, a subclass does not need to override this. However, if the subclass is added directly to the window manager (for example, ViewManager.addView(View, android.view.ViewGroup.LayoutParams)) then it should override this and start the action mode.

Runs the layout animation. Calling this method triggers a relayout of this view group.

This method tells the ViewGroup that the given View object, which should have this ViewGroup as its parent, should be kept around (re-displayed when the ViewGroup draws its children) even if it is removed from its parent. This allows animations, such as those used by android.app.Fragment and android.animation.LayoutTransition to animate the removal of views. A call to this method should always be accompanied by a later call to endViewTransition(android.view.View), such as after an animation on the View has finished, so that the View finally gets removed.

Tells this ViewGroup to suppress all layout() calls until layout suppression is disabled with a later call to suppressLayout(false). When layout suppression is disabled, a requestLayout() call is sent if layout() was attempted while layout was being suppressed.

Add any focusable views that are descendants of this view (possibly including this view if it is focusable itself) to views. If we are in touch mode, only add views that are also focusable in touch mode.

Add a listener for attach state changes. This listener will be called whenever this view is attached or detached from a window. Remove the listener using removeOnAttachStateChangeListener(android.view.View.OnAttachStateChangeListener).

Add a listener that will be called when the bounds of the view change due to layout processing.

Adds a listener which will receive unhandled KeyEvents. This must be called on the UI thread.

This method returns a ViewPropertyAnimator object, which can be used to animate specific properties on this View.

Convenience method for sending a AccessibilityEvent.TYPE_ANNOUNCEMENT AccessibilityEvent to suggest that an accessibility service announce the specified text to its users.

Note: The event generated with this API carries no semantic meaning, and accessibility services may choose to ignore it. Apps that accurately supply accessibility with the semantics of their UI should not need to specify what exactly is announced.

In general, do not attempt to generate announcements as confirmation message for simple actions like a button press. Label your controls concisely and precisely instead.

To convey significant UI changes like window changes, use android.app.Activity#setTitle(CharSequence) and setAccessibilityPaneTitle(java.lang.CharSequence).

Use setAccessibilityLiveRegion(int) to inform the user of changes to critical views within the user interface. These should still be used sparingly as they may generate announcements every time a View is updated.

Use setStateDescription(java.lang.CharSequence) to convey state changes to views within the user interface. While a live region may send different types of events generated by the view, state description will send AccessibilityEvent.TYPE_WINDOW_CONTENT_CHANGED events of type AccessibilityEvent.CONTENT_CHANGE_TYPE_STATE_DESCRIPTION.

For notifying users about errors, such as in a login screen with text that displays an "incorrect password" notification, set AccessibilityNodeInfo.setError(CharSequence) and dispatch an AccessibilityEvent.TYPE_WINDOW_CONTENT_CHANGED event with a change type of AccessibilityEvent.CONTENT_CHANGE_TYPE_ERROR, instead. Some widgets may expose methods that convey error states to accessibility automatically, such as android.widget.TextView#setError(CharSequence), which manages these accessibility semantics and event dispatch for callers.

Automatically fills the content of the virtual children within this view.

Views with virtual children support the Autofill Framework mainly by:

• Providing the metadata defining what the virtual children mean and how they can be autofilled.
• Implementing the methods that autofill the virtual children.

onProvideAutofillVirtualStructure(android.view.ViewStructure,int) is responsible for the former, this method is responsible for the latter - see autofill(android.view.autofill.AutofillValue) and onProvideAutofillVirtualStructure(android.view.ViewStructure,int) for more info about autofill.

If a child value is updated asynchronously, the next call to AutofillManager.notifyValueChanged(View, int, AutofillValue) must happen after the value was changed to the autofilled value. If not, the child will not be considered autofilled.

Note: To indicate that a virtual view was autofilled, ?android:attr/autofilledHighlight should be drawn over it until the data changes.

Automatically fills the content of this view with the value.

Views support the Autofill Framework mainly by:

• Providing the metadata defining what the view means and how it can be autofilled.
• Implementing the methods that autofill the view.

onProvideAutofillStructure(android.view.ViewStructure,int) is responsible for the former, this method is responsible for latter.

This method does nothing by default, but when overridden it typically:

1. Checks if the provided value matches the expected type (which is defined by getAutofillType()).
2. Checks if the view is editable - if it isn't, it should return right away.
3. Call the proper getter method on AutofillValue to fetch the actual value.
4. Pass the actual value to the equivalent setter in the view.

For example, a text-field view could implement the method this way:

@Override
  public void autofill(AutofillValue value) {
    if (!value.isText() || !this.isEditable()) {
       return;
    }
    CharSequence text = value.getTextValue();
    if (text != null) {
      this.setText(text);
    }
  }
  

If the value is updated asynchronously, the next call to AutofillManager.notifyValueChanged(View) must happen after the value was changed to the autofilled value. If not, the view will not be considered autofilled.

Note: After this method is called, the value returned by getAutofillValue() must be equal to the value passed to it, otherwise the view will not be highlighted as autofilled.

Trigger the scrollbars to draw. When invoked this method starts an animation to fade the scrollbars out after a default delay. If a subclass provides animated scrolling, the start delay should equal the duration of the scrolling animation.

The animation starts only if at least one of the scrollbars is enabled, as specified by isHorizontalScrollBarEnabled() and isVerticalScrollBarEnabled(). When the animation is started, this method returns true, and false otherwise. If the animation is started, this method calls invalidate(); in that case the caller should not call invalidate().

This method should be invoked every time a subclass directly updates the scroll parameters.

This method is automatically invoked by scrollBy(int,int) and scrollTo(int,int).