SharedElementCallback

fun onCaptureSharedElementSnapshot(
    sharedElement: View!,
    viewToGlobalMatrix: Matrix!,
    screenBounds: RectF!
): Parcelable!

Creates a snapshot of a shared element to be used by the remote Activity and reconstituted with onCreateSnapshotView. A null return value will mean that the remote Activity will have a null snapshot View in onSharedElementStart and onSharedElementEnd.

This is not called for Fragment Transitions.

fun onCreateSnapshotView(context: Context!, snapshot: Parcelable!): View!

Reconstitutes a snapshot View from a Parcelable returned in onCaptureSharedElementSnapshot to be used in onSharedElementStart and onSharedElementEnd. The returned View will be sized and positioned after this call so that it is ready to be added to the decor View's overlay.

This is not called for Fragment Transitions.

fun onMapSharedElements(
    names: (Mutable)List<String!>!,
    sharedElements: (Mutable)Map<String!, View!>!
): Unit

Lets the SharedElementCallback adjust the mapping of shared element names to Views.

fun onRejectSharedElements(rejectedSharedElements: (Mutable)List<View!>!): Unit

Called after onMapSharedElements when transferring shared elements in. Any shared elements that have no mapping will be in rejectedSharedElements. The elements remaining in rejectedSharedElements will be transitioned out of the Scene. If a View is removed from rejectedSharedElements, it must be handled by the SharedElementListener.

Views in rejectedSharedElements will have their position and size set to the position of the calling shared element, relative to the Window decor View and contain snapshots of the View from the calling Activity or Fragment. This view may be safely added to the decor View's overlay to remain in position.

This method is not called for Fragment Transitions. All rejected shared elements will be handled by the exit transition.

fun onSharedElementEnd(
    sharedElementNames: (Mutable)List<String!>!,
    sharedElements: (Mutable)List<View!>!,
    sharedElementSnapshots: (Mutable)List<View!>!
): Unit

In Activity Transitions, onSharedElementEnd is called immediately before capturing the end of the shared element state on enter and reenter transitions and immediately before capturing the start of the shared element state for exit and return transitions.

In Fragment Transitions, onSharedElementEnd is called immediately before capturing the end state of all shared element transitions.

This call can be used to adjust the transition end state by modifying the shared element Views. Note that no layout step will be executed between onSharedElementEnd and the transition state capture.

Any changes made in onSharedElementStart that are not updated during layout should be corrected in onSharedElementEnd. For example, rotation or scale will not be affected by layout and if changed in onSharedElementStart, it will also have to be reset in onSharedElementEnd again to correct the end state.

fun onSharedElementStart(
    sharedElementNames: (Mutable)List<String!>!,
    sharedElements: (Mutable)List<View!>!,
    sharedElementSnapshots: (Mutable)List<View!>!
): Unit

In Activity Transitions, onSharedElementStart is called immediately before capturing the start of the shared element state on enter and reenter transitions and immediately before capturing the end of the shared element state for exit and return transitions.

In Fragment Transitions, onSharedElementStart is called immediately before capturing the start state of all shared element transitions.

This call can be used to adjust the transition start state by modifying the shared element Views. Note that no layout step will be executed between onSharedElementStart and the transition state capture.

For Activity Transitions, any changes made in onSharedElementEnd that are not updated during layout should be corrected in onSharedElementStart for exit and return transitions. For example, rotation or scale will not be affected by layout and if changed in onSharedElementEnd, it will also have to be reset in onSharedElementStart again to correct the end state.

fun onSharedElementsArrived(
    sharedElementNames: (Mutable)List<String!>!,
    sharedElements: (Mutable)List<View!>!,
    listener: SharedElementCallback.OnSharedElementsReadyListener!
): Unit

Called during an Activity Transition when the shared elements have arrived at the final location and are ready to be transferred. This method is called for both the source and destination Activities.

When the shared elements are ready to be transferred, onSharedElementsReady must be called to trigger the transfer.

The default behavior is to trigger the transfer immediately.