我想显示相机预览并在预览准备好后立即开始捕获（基于camera2 API）
为了做到这一点，我构建了一个示例应用程序，该应用程序应在预览准备就绪时根据 Google camera2Video 示例 开始自动捕获视频，并根据我的需要进行修改。
这是我的
OnCreateif (null == savedInstanceState) {
getFragmentManager().beginTransaction()
.replace(R.id.container, camera2VideoFragment)
.commit();
}
Runnable runnable = new Runnable() {
@Override
public void run() {
while (!camera2VideoFragment.isCameraReady) {
try {
Log.d("camera status", String.valueOf(camera2VideoFragment.isCameraReady));
Thread.sleep(500);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
camera2VideoFragment.captureVideo();
}
};
runnable.run();
Camera2VideoFragmentCameraDevice.StateCallbackprivate CameraDevice.StateCallback mStateCallback = new CameraDevice.StateCallback() {
@Override
public void onOpened(CameraDevice cameraDevice) {
mCameraDevice = cameraDevice;
startPreview();
mCameraOpenCloseLock.release();
isCameraReady = true; // Setting the Boolean to true here
if (null != mTextureView) {
configureTransform(mTextureView.getWidth(), mTextureView.getHeight());
}
}
问题，
isCameraReady问题：如何知道预览何时准备好并自动开始捕捉视频，无需按任何按钮？（单击按钮将停止录制，而不是开始录制）
下面是
Camera2VideoFragmentpublic class Camera2VideoFragment extends Fragment
implements FragmentCompat.OnRequestPermissionsResultCallback {
private static final SparseIntArray ORIENTATIONS = new SparseIntArray();
private static final String TAG = "Camera2VideoFragment";
private static final int REQUEST_VIDEO_PERMISSIONS = 1;
private static final String FRAGMENT_DIALOG = "dialog";
static {
ORIENTATIONS.append(Surface.ROTATION_0, 90);
ORIENTATIONS.append(Surface.ROTATION_90, 0);
ORIENTATIONS.append(Surface.ROTATION_180, 270);
ORIENTATIONS.append(Surface.ROTATION_270, 180);
}
private AutoFitTextureView mTextureView;
private CameraDevice mCameraDevice;
private CameraCaptureSession mPreviewSession;
private TextureView.SurfaceTextureListener mSurfaceTextureListener
= new TextureView.SurfaceTextureListener() {
@Override
public void onSurfaceTextureAvailable(SurfaceTexture surfaceTexture,
int width, int height) {
openCamera(width, height);
}
@Override
public void onSurfaceTextureSizeChanged(SurfaceTexture surfaceTexture,
int width, int height) {
configureTransform(width, height);
}
@Override
public boolean onSurfaceTextureDestroyed(SurfaceTexture surfaceTexture) {
return true;
}
@Override
public void onSurfaceTextureUpdated(SurfaceTexture surfaceTexture) {
}
};
private Size mPreviewSize;
private Size mVideoSize;
private CaptureRequest.Builder mPreviewBuilder;
private MediaRecorder mMediaRecorder;
private static boolean mIsRecordingVideo;
private HandlerThread mBackgroundThread;
private Handler mBackgroundHandler;
private Semaphore mCameraOpenCloseLock = new Semaphore(1);
public static Boolean isCameraReady = false; // I add this variable in order to found when can I start recording
private CameraDevice.StateCallback mStateCallback = new CameraDevice.StateCallback() {
@Override
public void onOpened(CameraDevice cameraDevice) {
mCameraDevice = cameraDevice;
startPreview();
mCameraOpenCloseLock.release();
isCameraReady = true; // Here I set the Boolean to true
if (null != mTextureView) {
configureTransform(mTextureView.getWidth(), mTextureView.getHeight());
}
}
@Override
public void onDisconnected(CameraDevice cameraDevice) {
mCameraOpenCloseLock.release();
cameraDevice.close();
mCameraDevice = null;
isCameraReady = false;
}
@Override
public void onError(CameraDevice cameraDevice, int error) {
mCameraOpenCloseLock.release();
cameraDevice.close();
mCameraDevice = null;
Activity activity = getActivity();
if (null != activity) {
activity.finish();
}
isCameraReady = false;
}
};
public void captureVideo()
{
if (mIsRecordingVideo) {
stopRecordingVideo();
} else {
startRecordingVideo();
}
}
private void startBackgroundThread() {
mBackgroundThread = new HandlerThread("CameraBackground");
mBackgroundThread.start();
mBackgroundHandler = new Handler(mBackgroundThread.getLooper());
}
private void stopBackgroundThread() {
mBackgroundThread.quitSafely();
try {
mBackgroundThread.join();
mBackgroundThread = null;
mBackgroundHandler = null;
} catch (InterruptedException e) {
e.printStackTrace();
}
}
private void openCamera(int width, int height) {
if (!hasPermissionsGranted(VIDEO_PERMISSIONS)) {
requestVideoPermissions();
return;
}
final Activity activity = getActivity();
if (null == activity || activity.isFinishing()) {
return;
}
CameraManager manager = (CameraManager) activity.getSystemService(Context.CAMERA_SERVICE);
try {
Log.d(TAG, "tryAcquire");
if (!mCameraOpenCloseLock.tryAcquire(2500, TimeUnit.MILLISECONDS)) {
throw new RuntimeException("Time out waiting to lock camera opening.");
}
String cameraId = manager.getCameraIdList()[0];
// Choose the sizes for camera preview and video recording
CameraCharacteristics characteristics = manager.getCameraCharacteristics(cameraId);
StreamConfigurationMap map = characteristics
.get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP);
mVideoSize = chooseVideoSize(map.getOutputSizes(MediaRecorder.class));
mPreviewSize = chooseOptimalSize(map.getOutputSizes(SurfaceTexture.class),
width, height, mVideoSize);
int orientation = getResources().getConfiguration().orientation;
if (orientation == Configuration.ORIENTATION_LANDSCAPE) {
mTextureView.setAspectRatio(mPreviewSize.getWidth(), mPreviewSize.getHeight());
} else {
mTextureView.setAspectRatio(mPreviewSize.getHeight(), mPreviewSize.getWidth());
}
configureTransform(width, height);
mMediaRecorder = new MediaRecorder();
manager.openCamera(cameraId, mStateCallback, null);
} catch (CameraAccessException e) {
Toast.makeText(activity, "Cannot access the camera.", Toast.LENGTH_SHORT).show();
activity.finish();
} catch (NullPointerException e) {
// Currently an NPE is thrown when the Camera2API is used but not supported on the
// device this code runs.
ErrorDialog.newInstance(getString(R.string.camera_error))
.show(getChildFragmentManager(), FRAGMENT_DIALOG);
} catch (InterruptedException e) {
throw new RuntimeException("Interrupted while trying to lock camera opening.");
}
}
private void startPreview() {
if (null == mCameraDevice || !mTextureView.isAvailable() || null == mPreviewSize) {
return;
}
try {
setUpMediaRecorder();
SurfaceTexture texture = mTextureView.getSurfaceTexture();
assert texture != null;
texture.setDefaultBufferSize(mPreviewSize.getWidth(), mPreviewSize.getHeight());
mPreviewBuilder = mCameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_RECORD);
List<Surface> surfaces = new ArrayList<Surface>();
Surface previewSurface = new Surface(texture);
surfaces.add(previewSurface);
mPreviewBuilder.addTarget(previewSurface);
Surface recorderSurface = mMediaRecorder.getSurface();
surfaces.add(recorderSurface);
mPreviewBuilder.addTarget(recorderSurface);
mCameraDevice.createCaptureSession(surfaces, new CameraCaptureSession.StateCallback()
{
@Override
public void onConfigured(CameraCaptureSession cameraCaptureSession) {
mPreviewSession = cameraCaptureSession;
updatePreview();
}
@Override
public void onConfigureFailed(CameraCaptureSession cameraCaptureSession) {
Activity activity = getActivity();
if (null != activity) {
Toast.makeText(activity, "Failed", Toast.LENGTH_SHORT).show();
}
}
}, mBackgroundHandler);
isCameraReady = true;
} catch (CameraAccessException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
private void updatePreview() {
if (null == mCameraDevice) {
return;
}
try {
setUpCaptureRequestBuilder(mPreviewBuilder);
HandlerThread thread = new HandlerThread("CameraPreview");
thread.start();
mPreviewSession.setRepeatingRequest(mPreviewBuilder.build(), null, mBackgroundHandler);
} catch (CameraAccessException e) {
e.printStackTrace();
}
}
private void setUpCaptureRequestBuilder(CaptureRequest.Builder builder) {
builder.set(CaptureRequest.CONTROL_MODE, CameraMetadata.CONTROL_MODE_AUTO);
}
private void configureTransform(int viewWidth, int viewHeight) {
Activity activity = getActivity();
if (null == mTextureView || null == mPreviewSize || null == activity) {
return;
}
int rotation = activity.getWindowManager().getDefaultDisplay().getRotation();
Matrix matrix = new Matrix();
RectF viewRect = new RectF(0, 0, viewWidth, viewHeight);
RectF bufferRect = new RectF(0, 0, mPreviewSize.getHeight(), mPreviewSize.getWidth());
float centerX = viewRect.centerX();
float centerY = viewRect.centerY();
if (Surface.ROTATION_90 == rotation || Surface.ROTATION_270 == rotation) {
bufferRect.offset(centerX - bufferRect.centerX(), centerY - bufferRect.centerY());
matrix.setRectToRect(viewRect, bufferRect, Matrix.ScaleToFit.FILL);
float scale = Math.max(
(float) viewHeight / mPreviewSize.getHeight(),
(float) viewWidth / mPreviewSize.getWidth());
matrix.postScale(scale, scale, centerX, centerY);
matrix.postRotate(90 * (rotation - 2), centerX, centerY);
}
mTextureView.setTransform(matrix);
}
private void setUpMediaRecorder() throws IOException {
final Activity activity = getActivity();
if (null == activity) {
return;
}
mMediaRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
mMediaRecorder.setVideoSource(MediaRecorder.VideoSource.SURFACE);
mMediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);
mMediaRecorder.setOutputFile(getVideoFile(activity).getAbsolutePath());
mMediaRecorder.setVideoEncodingBitRate(10000000);
mMediaRecorder.setVideoFrameRate(30);
mMediaRecorder.setVideoSize(mVideoSize.getWidth(), mVideoSize.getHeight());
mMediaRecorder.setVideoEncoder(MediaRecorder.VideoEncoder.H264);
mMediaRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AAC);
int rotation = activity.getWindowManager().getDefaultDisplay().getRotation();
int orientation = ORIENTATIONS.get(rotation);
mMediaRecorder.setOrientationHint(orientation);
mMediaRecorder.prepare();
}
private void startRecordingVideo() {
try {
mIsRecordingVideo = true;
mMediaRecorder.start();
} catch (IllegalStateException e) {
e.printStackTrace();
}
}
private void stopRecordingVideo() {
mIsRecordingVideo = false;
mMediaRecorder.stop();
mMediaRecorder.reset();
Activity activity = getActivity();
if (null != activity) {
Toast.makeText(activity, "Video saved: " + getVideoFile(activity),
Toast.LENGTH_SHORT).show();
}
startPreview();
}
}
尝试一下这个希望它对你有用。
public class MainActivity extends AppCompatActivity {
private Uri fileUri;
public static final int MEDIA_TYPE_VIDEO = 2;
private static final int CAPTURE_VIDEO_ACTIVITY_REQUEST_CODE = 200;
public static MainActivity ActivityContext =null;
public static TextView output;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ActivityContext = this;
Button buttonRecording = (Button)findViewById(R.id.recording);
output = (TextView)findViewById(R.id.output);
// buttonRecording.setOnClickListener(new Button.OnClickListener() {
// @Override
// public void onClick(View arg0) {
// create new Intentwith with Standard Intent action that can be
// sent to have the camera application capture an video and return it.
Intent intent = new Intent(MediaStore.ACTION_VIDEO_CAPTURE);
// create a file to save the video
fileUri = getOutputMediaFileUri(MEDIA_TYPE_VIDEO);
// set the image file name
intent.putExtra(MediaStore.EXTRA_OUTPUT, fileUri);
// set the video image quality to high
intent.putExtra(MediaStore.EXTRA_VIDEO_QUALITY, 1);
// start the Video Capture Intent
startActivityForResult(intent, CAPTURE_VIDEO_ACTIVITY_REQUEST_CODE);
// }
// });
}
/** Create a file Uri for saving an image or video */
private static Uri getOutputMediaFileUri(int type){
return Uri.fromFile(getOutputMediaFile(type));
}
/** Create a File for saving an image or video */
private static File getOutputMediaFile(int type){
// Check that the SDCard is mounted
File mediaStorageDir = new File(Environment.getExternalStoragePublicDirectory(
Environment.DIRECTORY_PICTURES), "MyCameraVideo");
// Create the storage directory(MyCameraVideo) if it does not exist
if (! mediaStorageDir.exists()){
if (! mediaStorageDir.mkdirs()){
output.setText("Failed to create directory MyCameraVideo.");
Toast.makeText(ActivityContext, "Failed to create directory MyCameraVideo.",
Toast.LENGTH_LONG).show();
Log.d("MyCameraVideo", "Failed to create directory MyCameraVideo.");
return null;
}
}
// Create a media file name
// For unique file name appending current timeStamp with file name
java.util.Date date= new java.util.Date();
String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss")
.format(date.getTime());
File mediaFile;
if(type == MEDIA_TYPE_VIDEO) {
// For unique video file name appending current timeStamp with file name
mediaFile = new File(mediaStorageDir.getPath() + File.separator +
"VID_"+ timeStamp + ".mp4");
} else {
return null;
}
return mediaFile;
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
// After camera screen this code will excuted
if (requestCode == CAPTURE_VIDEO_ACTIVITY_REQUEST_CODE) {
if (resultCode == RESULT_OK) {
output.setText("Video File : " +data.getData());
// Video captured and saved to fileUri specified in the Intent
Toast.makeText(this, "Video saved to:" +
data.getData(), Toast.LENGTH_LONG).show();
} else if (resultCode == RESULT_CANCELED) {
output.setText("User cancelled the video capture.");
// User cancelled the video capture
Toast.makeText(this, "User cancelled the video capture.",
Toast.LENGTH_LONG).show();
} else {
output.setText("Video capture failed.");
// Video capture failed, advise user
Toast.makeText(this, "Video capture failed.",
Toast.LENGTH_LONG).show();
}
}
}
}