Callback

DISPATCH_MODE_CONTINUE_ON_SUBTREE

static val DISPATCH_MODE_CONTINUE_ON_SUBTREE: Int

Return value for getDispatchMode(): Dispatching of animation events should continue in the view hierarchy.

Value: 1

DISPATCH_MODE_STOP

static val DISPATCH_MODE_STOP: Int

Return value for getDispatchMode(): Dispatching of animation events should stop at this level in the view hierarchy, and no animation events should be dispatch to the subtree of the view hierarchy.

Value: 0

Callback

Callback(dispatchMode: Int)

Creates a new WindowInsetsAnimation callback with the given dispatch mode.

getDispatchMode

fun getDispatchMode(): Int

Retrieves the dispatch mode of this listener. Dispatch of the all animation events is hierarchical: It will starts at the root of the view hierarchy and then traverse it and invoke the callback of the specific View that is being traversed. The method may return either DISPATCH_MODE_CONTINUE_ON_SUBTREE to indicate that animation events should be propagated to the subtree of the view hierarchy, or DISPATCH_MODE_STOP to stop dispatching. In that case, all animation callbacks related to the animation passed in will be stopped from propagating to the subtree of the hierarchy.

Also note that DISPATCH_MODE_STOP behaves the same way as returning WindowInsets.CONSUMED during the regular insets dispatch in View.onApplyWindowInsets.

onEnd

open fun onEnd(animation: WindowInsetsAnimation): Unit

Called when an insets animation has ended.

onPrepare

open fun onPrepare(animation: WindowInsetsAnimation): Unit

Called when an insets animation is about to start and before the views have been laid out in the end state of the animation. The ordering of events during an insets animation is the following:

• Application calls WindowInsetsController.hide(int), WindowInsetsController.show(int), WindowInsetsController.controlWindowInsetsAnimation
• onPrepare is called on the view hierarchy listeners
• View.onApplyWindowInsets will be called with the end state of the animation
• View hierarchy gets laid out according to the changes the application has requested due to the new insets being dispatched
• onStart is called before the view hierarchy gets drawn in the new laid out state
• onProgress is called immediately after with the animation start state
• The frame gets drawn.

This ordering allows the application to inspect the end state after the animation has finished, and then revert to the starting state of the animation in the first onProgress callback by using post-layout view properties like View.setX and related methods.

Note that the animation might be cancelled before onStart is dispatched. On S and later, onEnd is immediately dispatched without an onStart in that case. On R, no callbacks are dispatched after onPrepare for such an animation.

Note: If the animation is application controlled by using WindowInsetsController.controlWindowInsetsAnimation, the end state of the animation is undefined as the application may decide on the end state only by passing in shown parameter when calling WindowInsetsAnimationController.finish. In this situation, the system will dispatch the insets in the opposite visibility state before the animation starts. Example: When controlling the input method with WindowInsetsController.controlWindowInsetsAnimation and the input method is currently showing, View.onApplyWindowInsets will receive a WindowInsets instance for which WindowInsets.isVisible will return false for WindowInsets.Type.ime.

onProgress

abstract fun onProgress(
    insets: WindowInsets, 
    runningAnimations: MutableList<WindowInsetsAnimation!>
): WindowInsets

Called when the insets change as part of running an animation. Note that even if multiple animations for different types are running, there will only be one progress callback per frame. The insets passed as an argument represents the overall state and will include all types, regardless of whether they are animating or not.

Note that insets dispatch is hierarchical: It will start at the root of the view hierarchy, and then traverse it and invoke the callback of the specific View being traversed. The method may return a modified instance by calling WindowInsets.inset(int, int, int, int) to indicate that a part of the insets have been used to offset or clip its children, and the children shouldn't worry about that part anymore. Furthermore, if getDispatchMode() returns DISPATCH_MODE_STOP, children of this view will not receive the callback anymore.

onStart

open fun onStart(
    animation: WindowInsetsAnimation, 
    bounds: WindowInsetsAnimation.Bounds
): WindowInsetsAnimation.Bounds

Called when an insets animation gets started.

Note that, like onProgress, dispatch of the animation start event is hierarchical: It will starts at the root of the view hierarchy and then traverse it and invoke the callback of the specific View that is being traversed. The method may return a modified instance of the bounds by calling Bounds.inset to indicate that a part of the insets have been used to offset or clip its children, and the children shouldn't worry about that part anymore. Furthermore, if getDispatchMode() returns DISPATCH_MODE_STOP, children of this view will not receive the callback anymore.