Animator

Kotlin |Java

abstract class Animator : Cloneable

kotlin.Any
↳	androidx.core.animation.Animator

Known Direct Subclasses AnimatorSet, ValueAnimator AnimatorSet This class plays a set of Animator objects in the specified order. ValueAnimator This class provides a simple timing engine for running animations which calculate animated values and set them on target objects.

Known Indirect Subclasses ObjectAnimator, TimeAnimator ObjectAnimator This subclass of ValueAnimator provides support for animating properties on target objects. TimeAnimator This class provides a simple callback mechanism to listeners that is synchronized with all other animators in the system.

This is the superclass for classes which provide basic support for animations which can be started, ended, and have AnimatorListeners added to them.

Summary

Nested classes
abstract	AnimatorListener An animation listener receives notifications from an animation.
abstract	AnimatorPauseListener A pause listener receives notifications from an animation when the animation is paused or resumed.
abstract	AnimatorUpdateListener Implementors of this interface can add themselves as update listeners to an ValueAnimator instance to receive callbacks on every animation frame, after the current frame's values have been calculated for that ValueAnimator.

Constants
static Long	DURATION_INFINITE The value used to indicate infinite duration (e.g. when Animators repeat infinitely).

Public constructors
<init>() This is the superclass for classes which provide basic support for animations which can be started, ended, and have AnimatorListeners added to them.

Public methods
open Unit	addListener(@NonNull listener: Animator.AnimatorListener) Adds a listener to the set of listeners that are sent events through the life of an animation, such as start, repeat, and end.
open Unit	addPauseListener(@NonNull listener: Animator.AnimatorPauseListener) Adds a pause listener to this animator.
open Unit	addUpdateListener(@NonNull listener: Animator.AnimatorUpdateListener) Adds a listener to the set of listeners that are sent update events through the life of an animation.
open Unit	cancel() Cancels the animation.
open Animator	clone()
open Unit	end() Ends the animation.
abstract Long	getDuration() Gets the duration of the animation.
open Interpolator?	getInterpolator() Returns the timing interpolator that this animation uses.
abstract Long	getStartDelay() The amount of time, in milliseconds, to delay processing the animation after start() is called.
open Long	getTotalDuration() Gets the total duration of the animation, accounting for animation sequences, start delay, and repeating.
open Boolean	isPaused() Returns whether this animator is currently in a paused state.
abstract Boolean	isRunning() Returns whether this Animator is currently running (having been started and gone past any initial startDelay period and not yet ended).
open Boolean	isStarted() Returns whether this Animator has been started and not yet ended.
open Unit	pause() Pauses a running animation.
open Unit	removeAllListeners() Removes all listeners and pauseListeners from this object.
open Unit	removeAllUpdateListeners() Removes all listeners from the set listening to frame updates for this animation.
open Unit	removeListener(@NonNull listener: Animator.AnimatorListener) Removes a listener from the set listening to this animation.
open Unit	removePauseListener(@NonNull listener: Animator.AnimatorPauseListener) Removes a pause listener from the set listening to this animation.
open Unit	removeUpdateListener(@NonNull listener: Animator.AnimatorUpdateListener) Removes a listener from the set listening to frame updates for this animation.
open Unit	resume() Resumes a paused animation, causing the animator to pick up where it left off when it was paused.
abstract Animator	setDuration(@IntRange(0) duration: Long) Sets the duration of the animation.
abstract Unit	setInterpolator(@Nullable value: Interpolator?) The interpolator used in calculating the elapsed fraction of the animation.
abstract Unit	setStartDelay(@IntRange(0) startDelay: Long) The amount of time, in milliseconds, to delay processing the animation after start() is called.
open Unit	setTarget(@Nullable target: Any?) Sets the target object whose property will be animated by this animation.
open Unit	setupEndValues() This method tells the object to use appropriate information to extract ending values for the animation.
open Unit	setupStartValues() This method tells the object to use appropriate information to extract starting values for the animation.
open Unit	start() Starts this animation.

Constants

DURATION_INFINITE

static val DURATION_INFINITE: Long

The value used to indicate infinite duration (e.g. when Animators repeat infinitely).

Value: -1

Public constructors

<init>

Animator()

This is the superclass for classes which provide basic support for animations which can be started, ended, and have AnimatorListeners added to them.

Public methods

addListener

open fun addListener(@NonNull listener: Animator.AnimatorListener): Unit

Adds a listener to the set of listeners that are sent events through the life of an animation, such as start, repeat, and end.

Parameters
listener	Animator.AnimatorListener: the listener to be added to the current set of listeners for this animation.

addPauseListener

open fun addPauseListener(@NonNull listener: Animator.AnimatorPauseListener): Unit

Adds a pause listener to this animator.

Parameters
listener	Animator.AnimatorPauseListener: the listener to be added to the current set of pause listeners for this animation.

addUpdateListener

open fun addUpdateListener(@NonNull listener: Animator.AnimatorUpdateListener): Unit

Adds a listener to the set of listeners that are sent update events through the life of an animation. This method is called on all listeners for every frame of the animation, after the values for the animation have been calculated.

Parameters
listener	Animator.AnimatorUpdateListener: the listener to be added to the current set of listeners for this animation.

cancel

open fun cancel(): Unit

Cancels the animation. Unlike end(), cancel() causes the animation to stop in its tracks, sending an AnimatorListener#onAnimationCancel(Animator) to its listeners, followed by an AnimatorListener#onAnimationEnd(Animator) message.

This method must be called on the thread that is running the animation.

clone

@NonNull open fun clone(): Animator

end

open fun end(): Unit

Ends the animation. This causes the animation to assign the end value of the property being animated, then calling the AnimatorListener#onAnimationEnd(Animator) method on its listeners.

This method must be called on the thread that is running the animation.

getDuration

abstract fun getDuration(): Long

Gets the duration of the animation.

Return
Long	The length of the animation, in milliseconds.

getInterpolator

@Nullable open fun getInterpolator(): Interpolator?

Returns the timing interpolator that this animation uses.

Return
Interpolator?	The timing interpolator for this animation.

getStartDelay

abstract fun getStartDelay(): Long

The amount of time, in milliseconds, to delay processing the animation after start() is called.

Return
Long	the number of milliseconds to delay running the animation

getTotalDuration

open fun getTotalDuration(): Long

Gets the total duration of the animation, accounting for animation sequences, start delay, and repeating.

When the animation repeats infinite times, or when any of the child animators does (via ValueAnimator#setRepeatCount(int)} to ValueAnimator#INFINITE), the total duration will be DURATION_INFINITE. Otherwise, the total duration is the sum of start delay and animation running time (i.e. duration of one iteration multiplied by the number of iterations).

Return
Long	Total time an animation takes to finish, starting from the time start() is called. DURATION_INFINITE will be returned if the animation or any child animation repeats infinite times.

isPaused

open fun isPaused(): Boolean

Returns whether this animator is currently in a paused state.

Return
Boolean	True if the animator is currently paused, false otherwise.

See Also

• #pause()
• #resume()

isRunning

abstract fun isRunning(): Boolean

Returns whether this Animator is currently running (having been started and gone past any initial startDelay period and not yet ended).

Return
Boolean	Whether the Animator is running.

isStarted

open fun isStarted(): Boolean

Returns whether this Animator has been started and not yet ended. For reusable Animators (which most Animators are, apart from the one-shot animator produced by createCircularReveal()), this state is a superset of isRunning(), because an Animator with a nonzero startDelay will return true for isStarted() during the delay phase, whereas isRunning() will return true only after the delay phase is complete. Non-reusable animators will always return true after they have been started, because they cannot return to a non-started state.

Return
Boolean	Whether the Animator has been started and not yet ended.

pause

open fun pause(): Unit

Pauses a running animation. This method should only be called on the same thread on which the animation was started. If the animation has not yet been or has since ended, then the call is ignored. Paused animations can be resumed by calling resume().

See Also

• #resume()
• #isPaused()
• AnimatorPauseListener

removeAllListeners

open fun removeAllListeners(): Unit

Removes all listeners and pauseListeners from this object.

removeAllUpdateListeners

open fun removeAllUpdateListeners(): Unit

Removes all listeners from the set listening to frame updates for this animation.

removeListener

open fun removeListener(@NonNull listener: Animator.AnimatorListener): Unit

Removes a listener from the set listening to this animation.

Parameters
listener	Animator.AnimatorListener: the listener to be removed from the current set of listeners for this animation.

removePauseListener

open fun removePauseListener(@NonNull listener: Animator.AnimatorPauseListener): Unit

Removes a pause listener from the set listening to this animation.

Parameters
listener	Animator.AnimatorPauseListener: the listener to be removed from the current set of pause listeners for this animation.

removeUpdateListener

open fun removeUpdateListener(@NonNull listener: Animator.AnimatorUpdateListener): Unit

Removes a listener from the set listening to frame updates for this animation.

Parameters
listener	Animator.AnimatorUpdateListener: the listener to be removed from the current set of update listeners for this animation.

resume

open fun resume(): Unit

Resumes a paused animation, causing the animator to pick up where it left off when it was paused. This method should only be called on the same thread on which the animation was started. Calls to resume() on an animator that is not currently paused will be ignored.

See Also

• #pause()
• #isPaused()
• AnimatorPauseListener

setDuration

@NonNull abstract fun setDuration(@IntRange(0) duration: Long): Animator

Sets the duration of the animation.

Parameters
duration	Long: The length of the animation, in milliseconds.

setInterpolator

abstract fun setInterpolator(@Nullable value: Interpolator?): Unit

The interpolator used in calculating the elapsed fraction of the animation. The interpolator determines whether the animation runs with linear or non-linear motion, such as acceleration and deceleration. The default value is androidx.core.animation.AccelerateDecelerateInterpolator.

Parameters
value	Interpolator?: the interpolator to be used by this animation, or null to use the default one.

setStartDelay

abstract fun setStartDelay(@IntRange(0) startDelay: Long): Unit

The amount of time, in milliseconds, to delay processing the animation after start() is called.

Parameters
startDelay	Long: The amount of the delay, in milliseconds

setTarget

open fun setTarget(@Nullable target: Any?): Unit

Sets the target object whose property will be animated by this animation. Not all subclasses operate on target objects (for example, ValueAnimator, but this method is on the superclass for the convenience of dealing generically with those subclasses that do handle targets.

Note: The target is stored as a weak reference internally to avoid leaking resources by having animators directly reference old targets. Therefore, you should ensure that animator targets always have a hard reference elsewhere.

Parameters
target	Any?: The object being animated

setupEndValues

open fun setupEndValues(): Unit

This method tells the object to use appropriate information to extract ending values for the animation. For example, a AnimatorSet object will pass this call to its child objects to tell them to set up the values. A ObjectAnimator object will use the information it has about its target object and PropertyValuesHolder objects to get the start values for its properties. A ValueAnimator object will ignore the request since it does not have enough information (such as a target object) to gather these values.

setupStartValues

open fun setupStartValues(): Unit

This method tells the object to use appropriate information to extract starting values for the animation. For example, a AnimatorSet object will pass this call to its child objects to tell them to set up the values. A ObjectAnimator object will use the information it has about its target object and PropertyValuesHolder objects to get the start values for its properties. A ValueAnimator object will ignore the request since it does not have enough information (such as a target object) to gather these values.

start

open fun start(): Unit

Starts this animation. If the animation has a nonzero startDelay, the animation will start running after that delay elapses. A non-delayed animation will have its initial value(s) set immediately, followed by calls to AnimatorListener#onAnimationStart(Animator) for any listeners of this animator.

The animation started by calling this method will be run on the thread that called this method. This thread should have a Looper on it (a runtime exception will be thrown if this is not the case). Also, if the animation will animate properties of objects in the view hierarchy, then the calling thread should be the UI thread for that view hierarchy.