abstract class Animator : Cloneable

Known direct subclasses
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

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 types

An animation listener receives notifications from an animation.

A pause listener receives notifications from an animation when the animation is paused or resumed.

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

const Long

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

Public constructors

Public functions

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.

Unit

Adds a pause listener to this animator.

Unit

Adds a listener to the set of listeners that are sent update events through the life of an animation.

Unit

Cancels the animation.

Animator
Unit
end()

Ends the animation.

abstract Long

Gets the duration of the animation.

Interpolator?

Returns the timing interpolator that this animation uses.

abstract Long

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

Long

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

Boolean

Returns whether this animator is currently in a paused state.

abstract Boolean

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

Boolean

Returns whether this Animator has been started and not yet ended.

Unit

Pauses a running animation.

Unit

Removes all listeners and pauseListeners from this object.

Unit

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

Unit

Removes a listener from the set listening to this animation.

Unit

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

Unit

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

Unit

Resumes a paused animation, causing the animator to pick up where it left off when it was paused.

abstract Animator
setDuration(duration: @IntRange(from = 0) Long)

Sets the duration of the animation.

abstract Unit

The interpolator used in calculating the elapsed fraction of the animation.

abstract Unit
setStartDelay(startDelay: @IntRange(from = 0) Long)

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

Unit
setTarget(target: Any?)

Sets the target object whose property will be animated by this animation.

Unit

This method tells the object to use appropriate information to extract ending values for the animation.

Unit

This method tells the object to use appropriate information to extract starting values for the animation.

Unit

Starts this animation.

Constants

DURATION_INFINITE

const val DURATION_INFINITE = -1: Long

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

Public constructors

Animator

Animator()

Public functions

addListener

fun addListener(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

fun addPauseListener(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

fun addUpdateListener(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

fun cancel(): Unit

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

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

clone

fun clone(): Animator

end

fun end(): Unit

Ends the animation. This causes the animation to assign the end value of the property being animated, then calling the onAnimationEnd 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.

Returns
Long

The length of the animation, in milliseconds.

getInterpolator

fun getInterpolator(): Interpolator?

Returns the timing interpolator that this animation uses.

Returns
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.

Returns
Long

the number of milliseconds to delay running the animation

getTotalDuration

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 setRepeatCount} to 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).

Returns
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

fun isPaused(): Boolean

Returns whether this animator is currently in a paused state.

Returns
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).

Returns
Boolean

Whether the Animator is running.

isStarted

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.

Returns
Boolean

Whether the Animator has been started and not yet ended.

pause

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 started or has since ended, then the call is ignored. Paused animations can be resumed by calling resume.

removeAllListeners

fun removeAllListeners(): Unit

Removes all listeners and pauseListeners from this object.

removeAllUpdateListeners

fun removeAllUpdateListeners(): Unit

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

removeListener

fun removeListener(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

fun removePauseListener(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

fun removeUpdateListener(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

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.

setDuration

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

Sets the duration of the animation.

Parameters
duration: @IntRange(from = 0) Long

The length of the animation, in milliseconds.

setInterpolator

abstract fun setInterpolator(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(startDelay: @IntRange(from = 0) Long): Unit

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

Parameters
startDelay: @IntRange(from = 0) Long

The amount of the delay, in milliseconds

setTarget

fun setTarget(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

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

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

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 onAnimationStart 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.