SharedElementCallback

Artifact: androidx.core:core

View Source

Added in 1.1.0

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Kotlin |Java

public abstract class SharedElementCallback

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Listener provided in setEnterSharedElementCallback and setExitSharedElementCallback to monitor the Activity transitions. The events can be used to customize Activity Transition behavior.

Summary

Nested types
public interface SharedElementCallback.OnSharedElementsReadyListener Listener to be called after onSharedElementsArrived when the shared elements are ready to be hidden in the source Activity and shown in the destination Activity.

Public constructors
SharedElementCallback()

Public methods
Parcelable	onCaptureSharedElementSnapshot(     View sharedElement,     Matrix viewToGlobalMatrix,     RectF screenBounds ) Creates a snapshot of a shared element to be used by the remote Activity and reconstituted with onCreateSnapshotView.
View	onCreateSnapshotView(Context context, Parcelable snapshot) Reconstitutes a snapshot View from a Parcelable returned in onCaptureSharedElementSnapshot to be used in onSharedElementStart and onSharedElementEnd.
void	onMapSharedElements(     List<String> names,     Map<String, View> sharedElements ) Lets the SharedElementCallback adjust the mapping of shared element names to Views.
void	onRejectSharedElements(List<View> rejectedSharedElements) Called after onMapSharedElements when transferring shared elements in.
void	onSharedElementEnd(     List<String> sharedElementNames,     List<View> sharedElements,     List<View> sharedElementSnapshots ) 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.
void	onSharedElementStart(     List<String> sharedElementNames,     List<View> sharedElements,     List<View> sharedElementSnapshots ) 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.
void	onSharedElementsArrived(     List<String> sharedElementNames,     List<View> sharedElements,     SharedElementCallback.OnSharedElementsReadyListener listener ) Called during an Activity Transition when the shared elements have arrived at the final location and are ready to be transferred.

Public constructors

SharedElementCallback

Added in 1.1.0

public SharedElementCallback()

Public methods

onCaptureSharedElementSnapshot

Added in 1.1.0

public Parcelable onCaptureSharedElementSnapshot(
    View sharedElement,
    Matrix viewToGlobalMatrix,
    RectF screenBounds
)

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.

Parameters
View sharedElement	The shared element View to create a snapshot for.
Matrix viewToGlobalMatrix	A matrix containing a transform from the view to the screen coordinates.
RectF screenBounds	The bounds of shared element in screen coordinate space. This is the bounds of the view with the viewToGlobalMatrix applied.

Returns
Parcelable	A snapshot to send to the remote Activity to be reconstituted with onCreateSnapshotView and passed into onSharedElementStart and onSharedElementEnd.

onCreateSnapshotView

Added in 1.1.0

public View onCreateSnapshotView(Context context, Parcelable snapshot)

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.

Parameters
Context context	The Context used to create the snapshot View.
Parcelable snapshot	The Parcelable returned by onCaptureSharedElementSnapshot.

Returns
View	A View to be sent in onSharedElementStart and onSharedElementEnd. A null value will produce a null snapshot value for those two methods.

onMapSharedElements

Added in 1.1.0

public void onMapSharedElements(
    List<String> names,
    Map<String, View> sharedElements
)

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

Parameters
List<String> names	The names of all shared elements transferred from the calling Activity or Fragment in the order they were provided.
Map<String, View> sharedElements	The mapping of shared element names to Views. The best guess will be filled into sharedElements based on the transitionNames.

onRejectSharedElements

Added in 1.1.0

public void onRejectSharedElements(List<View> rejectedSharedElements)

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.

Parameters
List<View> rejectedSharedElements	Views containing visual information of shared elements that are not part of the entering scene. These Views are positioned relative to the Window decor View. A View removed from this list will not be transitioned automatically.

onSharedElementEnd

Added in 1.1.0

public void onSharedElementEnd(
    List<String> sharedElementNames,
    List<View> sharedElements,
    List<View> sharedElementSnapshots
)

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.

Parameters
List<String> sharedElementNames	The names of the shared elements that were accepted into the View hierarchy.
List<View> sharedElements	The shared elements that are part of the View hierarchy.
List<View> sharedElementSnapshots	The Views containing snap shots of the shared element from the launching Window. These elements will not be part of the scene, but will be positioned relative to the Window decor View. This list will be null for Fragment Transitions.

onSharedElementStart

Added in 1.1.0

public void onSharedElementStart(
    List<String> sharedElementNames,
    List<View> sharedElements,
    List<View> sharedElementSnapshots
)

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.

Parameters
List<String> sharedElementNames	The names of the shared elements that were accepted into the View hierarchy.
List<View> sharedElements	The shared elements that are part of the View hierarchy.
List<View> sharedElementSnapshots	The Views containing snap shots of the shared element from the launching Window. These elements will not be part of the scene, but will be positioned relative to the Window decor View. This list is null for Fragment Transitions.

onSharedElementsArrived

Added in 1.1.0

public void onSharedElementsArrived(
    List<String> sharedElementNames,
    List<View> sharedElements,
    SharedElementCallback.OnSharedElementsReadyListener listener
)

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.

Parameters
List<String> sharedElementNames	The names of the shared elements that are being transferred..
List<View> sharedElements	The shared elements that are part of the View hierarchy.
SharedElementCallback.OnSharedElementsReadyListener listener	The listener to call when the shared elements are ready to be hidden in the source Activity or shown in the destination Activity.