New APIs for Android plugins that render to a Surface
Summary
#The Android embedder for Flutter introduces a new API, SurfaceProducer
,
which allows plugins to render to a Surface
without needing to manage what
the backing implementation is. Plugins using the older
createSurfaceTexture
API will continue to work with Impeller after the
next stable release, but are recommended to migrate to the new API.
Background
#An Android SurfaceTexture
is a backing implementation for a Surface
that uses an OpenGLES texture as the backing store.
For example, a plugin might display frames from a camera plugin:
In newer versions of the Android API (>= 29), Android introduced a
backend-agnostic HardwareBuffer
, which coincides with the minimum version
that Flutter will attempt to use the Vulkan renderer. The Android embedding
API needed to be updated to support a more generic Surface
creation API that
doesn't rely on OpenGLES.
Migration guide
#If you are using the older createSurfaceTexture
API, you should migrate to
the new createSurfaceProducer
API. The new API is more flexible and allows
the Flutter engine to opaquely pick the best implementation for the current
platform and API level.
-
Instead of creating a
SurfaceTextureEntry
, create aSurfaceProducer
:- TextureRegistry.SurfaceTextureEntry entry = textureRegistry.createSurfaceTexture(); + TextureRegistry.SurfaceProducer producer = textureRegistry.createSurfaceProducer();
-
Instead of creating a
new Surface(...)
, callgetSurface()
on theSurfaceProducer
:- Surface surface = new Surface(entry.surfaceTexture()); + Surface surface = producer.getSurface();
In order to conserve memory when the application is suspended in the background,
Android and Flutter may destroy a surface when it is no longer visible. To
ensure that the surface is recreated when the application is resumed, you should
use the provided setCallback
method to listen to surface lifecycle events:
surfaceProducer.setCallback(
new TextureRegistry.SurfaceProducer.Callback() {
@Override
public void onSurfaceCreated() {
// Do surface initialization here, and draw the current frame.
}
@Override
public void onSurfaceDestroyed() {
// Do surface cleanup here, and stop drawing frames.
}
}
);
A full example of using this new API can be found in PR 6989 for the
video_player_android
plugin.
Timeline
#Landed in version: 3.22
In stable release: 3.24
References
#API documentation:
Relevant issues:
Relevant PRs:
- PR 51061, where we test the new API in the engine tests.
- PR 6456, where we migrate the
video_player
plugin to use the new API. - PR 6461, where we migrate the
camera_android
plugin to use the new API. - PR 6989, where we add a full example of using the new API in the
video_player_android
plugin.
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