ChangeTransform

Artifact: androidx.transition:transition

View Source

Added in 1.0.0

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Kotlin |Java

class ChangeTransform : Transition

kotlin.Any
↳	androidx.transition.Transition
	↳	androidx.transition.ChangeTransform

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This Transition captures scale and rotation for Views before and after the scene change and animates those changes during the transition. A change in parent is handled as well by capturing the transforms from the parent before and after the scene change and animating those during the transition.

Summary

Public constructors
ChangeTransform()
ChangeTransform(context: Context, attrs: AttributeSet)

Public functions
Unit	captureEndValues(transitionValues: TransitionValues) Captures the values in the end scene for the properties that this transition monitors.
Unit	captureStartValues(transitionValues: TransitionValues) Captures the values in the start scene for the properties that this transition monitors.
Animator?	createAnimator(     sceneRoot: ViewGroup,     startValues: TransitionValues?,     endValues: TransitionValues? ) This method creates an animation that will be run for this transition given the information in the startValues and endValues structures captured earlier for the start and end scenes.
Boolean	getReparent() Returns whether parent changes will be tracked by the ChangeTransform.
Boolean	getReparentWithOverlay() Returns whether changes to parent should use an overlay or not.
Array<String!>	getTransitionProperties() Returns the set of property names used stored in the TransitionValues object passed into captureStartValues that this transition cares about for the purposes of canceling overlapping animations.
Unit	setReparent(reparent: Boolean) Sets whether parent changes will be tracked by the ChangeTransform.
Unit	setReparentWithOverlay(reparentWithOverlay: Boolean) Sets whether changes to parent should use an overlay or not.

Inherited Constants
From androidx.transition.Transition const Int MATCH_ID = 3 With setMatchOrder, chooses to match by getId. const Int MATCH_INSTANCE = 1 With setMatchOrder, chooses to match by View instance. const Int MATCH_ITEM_ID = 4 With setMatchOrder, chooses to match by the android.widget.Adapter item id. const Int MATCH_NAME = 2 With setMatchOrder, chooses to match by getTransitionName.

Inherited functions

From androidx.transition.Transition Transition addListener(listener: Transition.TransitionListener) Adds a listener to the set of listeners that are sent events through the life of an animation, such as start, repeat, and end. Transition addTarget(targetId: @IdRes Int) Adds the id of a target view that this Transition is interested in animating. Transition addTarget(targetName: String) Adds the transitionName of a target view that this Transition is interested in animating. Transition addTarget(targetType: Class<Any!>) Adds the Class of a target view that this Transition is interested in animating. Transition addTarget(target: View) Sets the target view instances that this Transition is interested in animating. Transition clone() Transition excludeChildren(targetId: @IdRes Int, exclude: Boolean) Whether to add the children of the given id to the list of targets to exclude from this transition. Transition excludeChildren(target: View, exclude: Boolean) Whether to add the children of given target to the list of target children to exclude from this transition. Transition excludeChildren(type: Class<Any!>, exclude: Boolean) Whether to add the given type to the list of types whose children should be excluded from this transition. Transition excludeTarget(targetId: @IdRes Int, exclude: Boolean) Whether to add the given id to the list of target ids to exclude from this transition. Transition excludeTarget(targetName: String, exclude: Boolean) Whether to add the given transitionName to the list of target transitionNames to exclude from this transition. Transition excludeTarget(target: View, exclude: Boolean) Whether to add the given target to the list of targets to exclude from this transition. Transition excludeTarget(type: Class<Any!>, exclude: Boolean) Whether to add the given type to the list of types to exclude from this transition. Long getDuration() Returns the duration set on this transition. Rect? getEpicenter() Returns the epicenter as specified by the android.transition.Transition.EpicenterCallback or null if no callback exists. Transition.EpicenterCallback? getEpicenterCallback() Returns the callback used to find the epicenter of the Transition. TimeInterpolator? getInterpolator() Returns the interpolator set on this transition. String getName() Returns the name of this Transition. PathMotion getPathMotion() Returns the algorithm object used to interpolate along two dimensions. TransitionPropagation? getPropagation() Returns the android.transition.TransitionPropagation used to calculate Animator start delays. Transition getRootTransition() If this Transition is not part of a TransitionSet, this is returned. Long getStartDelay() Returns the startDelay set on this transition. (Mutable)List<Int!> getTargetIds() Returns the array of target IDs that this transition limits itself to tracking and animating. (Mutable)List<String!>? getTargetNames() Returns the list of target transitionNames that this transition limits itself to tracking and animating. (Mutable)List<Class<Any!>!>? getTargetTypes() Returns the list of target transitionNames that this transition limits itself to tracking and animating. (Mutable)List<View!> getTargets() Returns the array of target views that this transition limits itself to tracking and animating. TransitionValues? getTransitionValues(view: View, start: Boolean) This method can be called by transitions to get the TransitionValues for any particular view during the transition-playing process. Boolean isSeekingSupported() Returns true if the Transition can be used by controlDelayedTransition. Boolean isTransitionRequired(     startValues: TransitionValues?,     endValues: TransitionValues? ) Returns whether or not the transition should create an Animator, based on the values captured during captureStartValues and captureEndValues. Transition removeListener(listener: Transition.TransitionListener) Removes a listener from the set listening to this animation. Transition removeTarget(target: Class<Any!>) Removes the given target from the list of targets that this Transition is interested in animating. Transition removeTarget(targetId: @IdRes Int) Removes the given targetId from the list of ids that this Transition is interested in animating. Transition removeTarget(targetName: String) Removes the given targetName from the list of transitionNames that this Transition is interested in animating. Transition removeTarget(target: View) Removes the given target from the list of targets that this Transition is interested in animating. Transition setDuration(duration: Long) Sets the duration of this transition. Unit setEpicenterCallback(epicenterCallback: Transition.EpicenterCallback?) Sets the callback to use to find the epicenter of a Transition. Transition setInterpolator(interpolator: TimeInterpolator?) Sets the interpolator of this transition. Unit setMatchOrder(matches: IntArray?) Sets the order in which Transition matches View start and end values. Unit setPathMotion(pathMotion: PathMotion?) Sets the algorithm used to calculate two-dimensional interpolation. Unit setPropagation(transitionPropagation: TransitionPropagation?) Sets the method for determining Animator start delays. Transition setStartDelay(startDelay: Long) Sets the startDelay of this transition. String toString()

Public constructors

ChangeTransform

Added in 1.0.0

ChangeTransform()

ChangeTransform

Added in 1.0.0

ChangeTransform(context: Context, attrs: AttributeSet)

Public functions

captureEndValues

fun captureEndValues(transitionValues: TransitionValues): Unit

Captures the values in the end scene for the properties that this transition monitors. These values are then passed as the endValues structure in a later call to createAnimator. The main concern for an implementation is what the properties are that the transition cares about and what the values are for all of those properties. The start and end values will be compared later during the createAnimator method to determine what, if any, animations, should be run.

Subclasses must implement this method. The method should only be called by the transition system; it is not intended to be called from external classes.

Parameters

transitionValues: TransitionValues

The holder for any values that the Transition wishes to store. Values are stored in the values field of this TransitionValues object and are keyed from a String value. For example, to store a view's rotation value, a transition might call transitionValues.values.put("appname:transitionname:rotation", view.getRotation()). The target view will already be stored in the transitionValues structure when this method is called.

See also
captureStartValues
createAnimator

captureStartValues

fun captureStartValues(transitionValues: TransitionValues): Unit

Captures the values in the start scene for the properties that this transition monitors. These values are then passed as the startValues structure in a later call to createAnimator. The main concern for an implementation is what the properties are that the transition cares about and what the values are for all of those properties. The start and end values will be compared later during the createAnimator method to determine what, if any, animations, should be run.

Subclasses must implement this method. The method should only be called by the transition system; it is not intended to be called from external classes.

Parameters

transitionValues: TransitionValues

The holder for any values that the Transition wishes to store. Values are stored in the values field of this TransitionValues object and are keyed from a String value. For example, to store a view's rotation value, a transition might call transitionValues.values.put("appname:transitionname:rotation", view.getRotation()). The target view will already be stored in the transitionValues structure when this method is called.

See also
captureEndValues
createAnimator

createAnimator

fun createAnimator(
    sceneRoot: ViewGroup,
    startValues: TransitionValues?,
    endValues: TransitionValues?
): Animator?

This method creates an animation that will be run for this transition given the information in the startValues and endValues structures captured earlier for the start and end scenes. Subclasses of Transition should override this method. The method should only be called by the transition system; it is not intended to be called from external classes.

This method is called by the transition's parent (all the way up to the topmost Transition in the hierarchy) with the sceneRoot and start/end values that the transition may need to set up initial target values and construct an appropriate animation. For example, if an overall Transition is a TransitionSet consisting of several child transitions in sequence, then some of the child transitions may want to set initial values on target views prior to the overall Transition commencing, to put them in an appropriate state for the delay between that start and the child Transition start time. For example, a transition that fades an item in may wish to set the starting alpha value to 0, to avoid it blinking in prior to the transition actually starting the animation. This is necessary because the scene change that triggers the Transition will automatically set the end-scene on all target views, so a Transition that wants to animate from a different value should set that value prior to returning from this method.

Additionally, a Transition can perform logic to determine whether the transition needs to run on the given target and start/end values. For example, a transition that resizes objects on the screen may wish to avoid running for views which are not present in either the start or end scenes.

If there is an animator created and returned from this method, the transition mechanism will apply any applicable duration, startDelay, and interpolator to that animation and start it. A return value of null indicates that no animation should run. The default implementation returns null.

The method is called for every applicable target object, which is stored in the view field.

Parameters
sceneRoot: ViewGroup	The root of the transition hierarchy.
startValues: TransitionValues?	The values for a specific target in the start scene.
endValues: TransitionValues?	The values for the target in the end scene.

Returns
Animator?	A Animator to be started at the appropriate time in the overall transition for this scene change. A null value means no animation should be run.

getReparent

Added in 1.0.0

fun getReparent(): Boolean

Returns whether parent changes will be tracked by the ChangeTransform. If parent changes are tracked, then the transform will adjust to the transforms of the different parents. If they aren't tracked, only the transforms of the transitioning view will be tracked. Default is true.

Returns
Boolean	whether parent changes will be tracked by the ChangeTransform.

getReparentWithOverlay

Added in 1.0.0

fun getReparentWithOverlay(): Boolean

Returns whether changes to parent should use an overlay or not. When the parent change doesn't use an overlay, it affects the transforms of the child. The default value is true.

Note: when Overlays are not used when a parent changes, a view can be clipped when it moves outside the bounds of its parent. Setting setClipChildren and setClipToPadding can help. Also, when Overlays are not used and the parent is animating its location, the position of the child view will be relative to its parent's final position, so it may appear to "jump" at the beginning.

Returns
Boolean	true when a changed parent should execute the transition inside the scene root's overlay or false if a parent change only affects the transform of the transitioning view.

getTransitionProperties

fun getTransitionProperties(): Array<String!>

Returns the set of property names used stored in the TransitionValues object passed into captureStartValues that this transition cares about for the purposes of canceling overlapping animations. When any transition is started on a given scene root, all transitions currently running on that same scene root are checked to see whether the properties on which they based their animations agree with the end values of the same properties in the new transition. If the end values are not equal, then the old animation is canceled since the new transition will start a new animation to these new values. If the values are equal, the old animation is allowed to continue and no new animation is started for that transition.

A transition does not need to override this method. However, not doing so will mean that the cancellation logic outlined in the previous paragraph will be skipped for that transition, possibly leading to artifacts as old transitions and new transitions on the same targets run in parallel, animating views toward potentially different end values.

Returns
Array<String!>	An array of property names as described in the class documentation for TransitionValues. The default implementation returns null.

setReparent

Added in 1.0.0

fun setReparent(reparent: Boolean): Unit

Sets whether parent changes will be tracked by the ChangeTransform. If parent changes are tracked, then the transform will adjust to the transforms of the different parents. If they aren't tracked, only the transforms of the transitioning view will be tracked. Default is true.

Parameters
reparent: Boolean	Set to true to track parent changes or false to only track changes of the transitioning view without considering the parent change.

setReparentWithOverlay

Added in 1.0.0

fun setReparentWithOverlay(reparentWithOverlay: Boolean): Unit

Sets whether changes to parent should use an overlay or not. When the parent change doesn't use an overlay, it affects the transforms of the child. The default value is true.

Note: when Overlays are not used when a parent changes, a view can be clipped when it moves outside the bounds of its parent. Setting setClipChildren and setClipToPadding can help. Also, when Overlays are not used and the parent is animating its location, the position of the child view will be relative to its parent's final position, so it may appear to "jump" at the beginning.

Parameters
reparentWithOverlay: Boolean	true when a changed parent should execute the transition inside the scene root's overlay or falseif a parent change only affects the transform of the transitioning view.