Choreographer


public final class Choreographer
extends Object

java.lang.Object
   ↳ android.view.Choreographer


Coordinates the timing of animations, input and drawing.

The choreographer receives timing pulses (such as vertical synchronization) from the display subsystem then schedules work to occur as part of rendering the next display frame.

Applications typically interact with the choreographer indirectly using higher level abstractions in the animation framework or the view hierarchy. Here are some examples of things you can do using the higher-level APIs.

However, there are a few cases where you might want to use the functions of the choreographer directly in your application. Here are some examples.

  • If your application does its rendering in a different thread, possibly using GL, or does not use the animation framework or view hierarchy at all and you want to ensure that it is appropriately synchronized with the display, then use Choreographer#postFrameCallback.
  • ... and that's about it.

Each Looper thread has its own choreographer. Other threads can post callbacks to run on the choreographer but they will run on the Looper to which the choreographer belongs.

Summary

Nested classes

interface Choreographer.FrameCallback

Implement this interface to receive a callback when a new display frame is being rendered. 

class Choreographer.FrameData

The payload for VsyncCallback which includes frame information such as when the frame started being rendered, and multiple possible frame timelines and their information including deadline and expected present time. 

class Choreographer.FrameTimeline

Holds data that describes one possible VSync frame event to render at. 

interface Choreographer.VsyncCallback

Implement this interface to receive a callback to start the next frame. 

Public methods

static Choreographer getInstance()

Gets the choreographer for the calling thread.

void postFrameCallback(Choreographer.FrameCallback callback)

Posts a frame callback to run on the next frame.

void postFrameCallbackDelayed(Choreographer.FrameCallback callback, long delayMillis)

Posts a frame callback to run on the next frame after the specified delay.

void postVsyncCallback(Choreographer.VsyncCallback callback)

Posts a vsync callback to run on the next frame.

void removeFrameCallback(Choreographer.FrameCallback callback)

Removes a previously posted frame callback.

void removeVsyncCallback(Choreographer.VsyncCallback callback)

Removes a previously posted vsync callback.

Inherited methods

Public methods

getInstance

Added in API level 16
public static Choreographer getInstance ()

Gets the choreographer for the calling thread. Must be called from a thread that already has a Looper associated with it.

Returns
Choreographer The choreographer for this thread.

Throws
IllegalStateException if the thread does not have a looper.

postFrameCallback

Added in API level 16
public void postFrameCallback (Choreographer.FrameCallback callback)

Posts a frame callback to run on the next frame.

The callback runs once then is automatically removed.

Parameters
callback Choreographer.FrameCallback: The frame callback to run during the next frame.

postFrameCallbackDelayed

Added in API level 16
public void postFrameCallbackDelayed (Choreographer.FrameCallback callback, 
                long delayMillis)

Posts a frame callback to run on the next frame after the specified delay.

The callback runs once then is automatically removed.

Parameters
callback Choreographer.FrameCallback: The frame callback to run during the next frame.

delayMillis long: The delay time in milliseconds.

postVsyncCallback

Added in API level 33
public void postVsyncCallback (Choreographer.VsyncCallback callback)

Posts a vsync callback to run on the next frame.

The callback runs once then is automatically removed.

Parameters
callback Choreographer.VsyncCallback: The vsync callback to run during the next frame. This value cannot be null.

removeFrameCallback

Added in API level 16
public void removeFrameCallback (Choreographer.FrameCallback callback)

Removes a previously posted frame callback.

Parameters
callback Choreographer.FrameCallback: The frame callback to remove.

removeVsyncCallback

Added in API level 33
public void removeVsyncCallback (Choreographer.VsyncCallback callback)

Removes a previously posted vsync callback.

Parameters
callback Choreographer.VsyncCallback: The vsync callback to remove. This value may be null.