TextureViewImplementation.java
/*
* Copyright 2019 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package androidx.camera.view;
import static androidx.camera.core.SurfaceRequest.Result;
import android.graphics.SurfaceTexture;
import android.util.Log;
import android.view.Surface;
import android.view.TextureView;
import android.view.View;
import android.widget.FrameLayout;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.camera.core.Preview;
import androidx.camera.core.SurfaceRequest;
import androidx.camera.core.impl.utils.executor.CameraXExecutors;
import androidx.camera.core.impl.utils.futures.FutureCallback;
import androidx.camera.core.impl.utils.futures.Futures;
import androidx.concurrent.futures.CallbackToFutureAdapter;
import androidx.core.content.ContextCompat;
import androidx.core.util.Preconditions;
import com.google.common.util.concurrent.ListenableFuture;
/**
* The {@link TextureView} implementation for {@link PreviewView}
*/
final class TextureViewImplementation extends PreviewViewImplementation {
private static final String TAG = "TextureViewImpl";
TextureView mTextureView;
SurfaceTexture mSurfaceTexture;
ListenableFuture<Result> mSurfaceReleaseFuture;
SurfaceRequest mSurfaceRequest;
@Nullable
@Override
View getPreview() {
return mTextureView;
}
@NonNull
@Override
public Preview.SurfaceProvider getSurfaceProvider() {
return (surfaceRequest) -> {
mResolution = surfaceRequest.getResolution();
initializePreview();
if (mSurfaceRequest != null) {
mSurfaceRequest.willNotProvideSurface();
}
mSurfaceRequest = surfaceRequest;
surfaceRequest.addRequestCancellationListener(
ContextCompat.getMainExecutor(mTextureView.getContext()), () -> {
if (mSurfaceRequest != null && mSurfaceRequest == surfaceRequest) {
mSurfaceRequest = null;
mSurfaceReleaseFuture = null;
}
});
tryToProvidePreviewSurface();
};
}
@Override
public void initializePreview() {
Preconditions.checkNotNull(mParent);
Preconditions.checkNotNull(mResolution);
mTextureView = new TextureView(mParent.getContext());
mTextureView.setLayoutParams(
new FrameLayout.LayoutParams(mResolution.getWidth(), mResolution.getHeight()));
mTextureView.setSurfaceTextureListener(new TextureView.SurfaceTextureListener() {
@Override
public void onSurfaceTextureAvailable(final SurfaceTexture surfaceTexture,
final int width, final int height) {
mSurfaceTexture = surfaceTexture;
tryToProvidePreviewSurface();
}
@Override
public void onSurfaceTextureSizeChanged(final SurfaceTexture surfaceTexture,
final int width, final int height) {
Log.d(TAG, "onSurfaceTextureSizeChanged(width:" + width + ", height: " + height
+ " )");
}
/**
* If a surface has been provided to the camera (meaning
* {@link TextureViewImplementation#mSurfaceRequest} is null), but the camera
* is still using it (meaning {@link TextureViewImplementation#mSurfaceReleaseFuture} is
* not null), a listener must be added to
* {@link TextureViewImplementation#mSurfaceReleaseFuture} to ensure the surface
* is properly released after the camera is done using it.
*
* @param surfaceTexture The {@link SurfaceTexture} about to be destroyed.
* @return false if the camera is not done with the surface, true otherwise.
*/
@Override
public boolean onSurfaceTextureDestroyed(final SurfaceTexture surfaceTexture) {
mSurfaceTexture = null;
if (mSurfaceRequest == null && mSurfaceReleaseFuture != null) {
Futures.addCallback(mSurfaceReleaseFuture,
new FutureCallback<Result>() {
@Override
public void onSuccess(Result result) {
Preconditions.checkState(result.getResultCode()
!= Result.RESULT_SURFACE_ALREADY_PROVIDED,
"Unexpected result from SurfaceRequest. Surface was "
+ "provided twice.");
surfaceTexture.release();
}
@Override
public void onFailure(Throwable t) {
throw new IllegalStateException("SurfaceReleaseFuture did not "
+ "complete nicely.", t);
}
}, ContextCompat.getMainExecutor(mTextureView.getContext()));
return false;
} else {
return true;
}
}
@Override
public void onSurfaceTextureUpdated(final SurfaceTexture surfaceTexture) {
}
});
// Even though PreviewView calls `removeAllViews()` before calling init(), it should be
// called again here in case `getPreviewSurfaceProvider()` is called more than once on
// the same TextureViewImplementation instance.
mParent.removeAllViews();
mParent.addView(mTextureView);
}
@SuppressWarnings("WeakerAccess")
void tryToProvidePreviewSurface() {
if (mResolution == null || mSurfaceTexture == null || mSurfaceRequest == null) {
return;
}
mSurfaceTexture.setDefaultBufferSize(mResolution.getWidth(), mResolution.getHeight());
final Surface surface = new Surface(mSurfaceTexture);
final ListenableFuture<Result> surfaceReleaseFuture =
CallbackToFutureAdapter.getFuture(completer -> {
mSurfaceRequest.provideSurface(surface,
CameraXExecutors.directExecutor(), completer::set);
return "provideSurface[request=" + mSurfaceRequest + " surface=" + surface
+ "]";
});
mSurfaceReleaseFuture = surfaceReleaseFuture;
mSurfaceReleaseFuture.addListener(() -> {
surface.release();
if (mSurfaceReleaseFuture == surfaceReleaseFuture) {
mSurfaceReleaseFuture = null;
}
}, ContextCompat.getMainExecutor(mTextureView.getContext()));
mSurfaceRequest = null;
onSurfaceProvided();
}
}