Animator

public abstract class Animator
extends Object implements Cloneable

java.lang.Object
   ↳ androidx.core.animation.Animator


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

interface Animator.AnimatorListener

An animation listener receives notifications from an animation. 

interface Animator.AnimatorPauseListener

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

interface Animator.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

long DURATION_INFINITE

The value used to indicate infinite duration (e.g.

Public constructors

Animator()

Public methods

void addListener(Animator.AnimatorListener listener)

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

void addPauseListener(Animator.AnimatorPauseListener listener)

Adds a pause listener to this animator.

void addUpdateListener(Animator.AnimatorUpdateListener listener)

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

void cancel()

Cancels the animation.

Animator clone()
void end()

Ends the animation.

abstract long getDuration()

Gets the duration of the animation.

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.

long getTotalDuration()

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

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).

boolean isStarted()

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

void pause()

Pauses a running animation.

void removeAllListeners()

Removes all listeners and pauseListeners from this object.

void removeAllUpdateListeners()

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

void removeListener(Animator.AnimatorListener listener)

Removes a listener from the set listening to this animation.

void removePauseListener(Animator.AnimatorPauseListener listener)

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

void removeUpdateListener(Animator.AnimatorUpdateListener listener)

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

void resume()

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

abstract Animator setDuration(long duration)

Sets the duration of the animation.

abstract void setInterpolator(Interpolator value)

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

abstract void setStartDelay(long startDelay)

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

void setTarget(Object target)

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

void setupEndValues()

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

void setupStartValues()

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

void start()

Starts this animation.

Inherited methods

Constants

DURATION_INFINITE

public static final long DURATION_INFINITE

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

Constant Value: -1 (0xffffffffffffffff)

Public constructors

Animator

public Animator ()

Public methods

addListener

public void addListener (Animator.AnimatorListener listener)

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

public void addPauseListener (Animator.AnimatorPauseListener listener)

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

public void addUpdateListener (Animator.AnimatorUpdateListener listener)

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

public void cancel ()

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

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

clone

public Animator clone ()

Returns
Animator

end

public void end ()

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

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

getDuration

public abstract long getDuration ()

Gets the duration of the animation.

Returns
long The length of the animation, in milliseconds.

getInterpolator

public Interpolator getInterpolator ()

Returns the timing interpolator that this animation uses.

Returns
Interpolator The timing interpolator for this animation.

getStartDelay

public abstract long getStartDelay ()

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

public long getTotalDuration ()

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).

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

public boolean isPaused ()

Returns whether this animator is currently in a paused state.

Returns
boolean True if the animator is currently paused, false otherwise.

See also:

isRunning

public abstract boolean isRunning ()

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

public boolean isStarted ()

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

public void pause ()

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

public void removeAllListeners ()

Removes all listeners and pauseListeners from this object.

removeAllUpdateListeners

public void removeAllUpdateListeners ()

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

removeListener

public void removeListener (Animator.AnimatorListener listener)

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

public void removePauseListener (Animator.AnimatorPauseListener listener)

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

public void removeUpdateListener (Animator.AnimatorUpdateListener listener)

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

public void resume ()

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

public abstract Animator setDuration (long duration)

Sets the duration of the animation.

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

Returns
Animator

setInterpolator

public abstract void setInterpolator (Interpolator value)

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 AccelerateDecelerateInterpolator.

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

setStartDelay

public abstract void setStartDelay (long startDelay)

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

public void setTarget (Object target)

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 Object: The object being animated

setupEndValues

public void setupEndValues ()

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

public void setupStartValues ()

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

public void start ()

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 Animator.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.