我创建了一个包含自定义SurfaceView的库：
public class CameraPreview extends SurfaceView implements SurfaceHolder.Callback {
private static final String TAG = CameraPreview.class.getSimpleName();
private final SurfaceHolder mHolder;
private final Camera mCamera;
private final int mCameraId;
public CameraPreview(Context context, Camera camera, int cameraId) {
super(context);
mCamera = camera;
mCameraId = cameraId;
mHolder = getHolder();
mHolder.addCallback(this);
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
// The Surface has been created, now tell the camera where to draw the preview.
try {
mCamera.setPreviewDisplay(holder);
mCamera.startPreview();
} catch (IOException e) {
Log.e(TAG, "Error setting camera preview: " + e.getMessage());
}
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
// If your preview can change or rotate, take care of those events here.
// Make sure to stop the preview before resizing or reformatting it.
if (mHolder.getSurface() == null) {
// preview surface does not exist
return;
}
// stop preview before making changes
try {
mCamera.stopPreview();
} catch (Exception e){
// ignore: tried to stop a non-existent preview
}
// Adjust orientation
final int rotation = CameraUtil.getAdjustedDisplayOrientation(getContext(), mCameraId);
mCamera.setDisplayOrientation(rotation);
// set preview size and make any resize, rotate or
// reformatting changes here
// start preview with new settings
try {
mCamera.setPreviewDisplay(mHolder);
mCamera.startPreview();
} catch (Exception e){
Log.d(TAG, "Error starting camera preview: " + e.getMessage());
}
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
// Empty. Take care of releasing the Camera preview in your activity.
}
}
我创建了另一个库类CameraPreview的实例：
public class LibraryClass implements PreciseCountdownTimer.PreciseCountdownTimerCallback {
private static final String TAG = LibraryClass.class.getSimpleName();
private static final long MAX_RECORD_TIME_MILLIS = 3000;
private static final long INTERVAL_MILLIS = 1000;
private static LibraryClass mInstance;
private Activity mActivity;
private CameraInitListener mCallback;
private int mCameraId = -1;
private Camera mCamera;
private CameraPreview mCameraPreview;
private MediaRecorder mMediaRecorder;
private PreciseCountdownTimer mTimer;
private boolean mIsRecording = false;
private File mTempVideoFile;
public static LibraryClass getInstance() {
if (mInstance == null) {
mInstance = new LibraryClass();
}
return mInstance;
}
// Call this in onResume of the activity
public void initialize(Activity activity) {
mActivity = activity;
try {
mCallback = (CameraInitListener) activity;
} catch (ClassCastException e) {
throw new ClassCastException(activity.getClass().getSimpleName()
+ " must implement CameraInitListener");
}
if (ViewUtil.checkValidRootView(activity)) {
PermissionUtil.requestPermissions(activity);
prepareCamera();
addCameraPreview();
prepareMediaRecorder();
prepareTimer();
mCallback.onCameraInitialized();
}
}
// Call this in onPause of the activity
public void release() {
releaseMediaRecorder();
releaseCamera();
removeCameraPreview();
releaseTimer();
}
public void startRecording() {
if (checkPermissions()) {
try {
mIsRecording = true;
mMediaRecorder.start();
mTimer.start();
Log.d(TAG, "Recording started.");
} catch (IllegalStateException e) {
releaseMediaRecorder();
releaseTimer();
}
} else {
releaseMediaRecorder();
}
}
public void stopRecording() {
mIsRecording = false;
mMediaRecorder.stop();
releaseMediaRecorder();
releaseTimer();
getSignedUrl();
}
@Override
public void onPreciseTimerTick(long remainingTime) {
}
@Override
public void onPreciseTimerFinished() {
mIsRecording = false;
mMediaRecorder.stop();
releaseMediaRecorder();
releaseTimer();
getSignedUrl();
}
private boolean checkPermissions() {
if (PermissionUtil.checkCameraPermission(mActivity)
&& PermissionUtil.checkRecordAudioPermission(mActivity)
&& PermissionUtil.checkWriteExternalStoragePermission(mActivity)) {
return true;
} else {
return false;
}
}
private void prepareCamera() {
mCameraId = CameraUtil.getFrontCameraId();
if (mCameraId != -1) {
try {
mCamera = Camera.open(mCameraId);
} catch (Exception e) {
Log.e(TAG, "Error initializing front camera.");
e.printStackTrace();
mCamera = null;
}
}
}
private void releaseCamera() {
if (mCamera != null){
mCamera.release();
mCamera = null;
}
}
private void addCameraPreview() {
if (mCamera == null) {
return;
}
mCameraPreview = new CameraPreview(mActivity, mCamera, mCameraId);
mCameraPreview.setLayoutParams(new FrameLayout.LayoutParams(100, 100, Gravity.TOP|Gravity.RIGHT));
mCameraPreview.setBackgroundColor(ContextCompat.getColor(mActivity, android.R.color.holo_red_dark));
final ViewGroup rootView = ViewUtil.getRootView(mActivity);
rootView.addView(mCameraPreview);
}
private void removeCameraPreview() {
if (mCameraPreview != null) {
final ViewGroup rootView = ViewUtil.getRootView(mActivity);
rootView.removeView(mCameraPreview);
}
}
private void prepareMediaRecorder() {
if (mCamera == null) {
return;
}
mCamera.unlock();
mMediaRecorder = new MediaRecorder();
mMediaRecorder.setCamera(mCamera);
mMediaRecorder.setAudioSource(MediaRecorder.AudioSource.CAMCORDER);
mMediaRecorder.setVideoSource(MediaRecorder.VideoSource.CAMERA);
mMediaRecorder.setProfile(CamcorderProfile.get(mCameraId, CamcorderProfile.QUALITY_HIGH));
// mTempVideoFile = FileUtil.getTempVideoFile(getContext());
mTempVideoFile = new File(Environment.getExternalStoragePublicDirectory(
Environment.DIRECTORY_MOVIES), DateUtil.getCurrentTimeStamp() + ".mp4");
mMediaRecorder.setOutputFile(mTempVideoFile.getAbsolutePath());
mMediaRecorder.setPreviewDisplay(mCameraPreview.getHolder().getSurface());
// mMediaRecorder.setOrientationHint(90);
try {
mMediaRecorder.prepare();
} catch (IllegalStateException|IOException e) {
Log.e(TAG, "Error preparing MediaRecorder: " + e.getMessage());
releaseMediaRecorder();
}
}
private void releaseMediaRecorder() {
if (mMediaRecorder != null) {
mMediaRecorder.reset();
mMediaRecorder.release();
mMediaRecorder = null;
}
if (mCamera != null) {
mCamera.lock();
}
}
private void prepareTimer() {
mTimer = new PreciseCountdownTimer(MAX_RECORD_TIME_MILLIS, INTERVAL_MILLIS, this);
}
private void releaseTimer() {
if (mTimer != null) {
mTimer.stop();
}
}
我设置了一些调试断点，没有调用任何SurfaceView方法：surfaceCreated，surfaceChanged，surfaceDestroyed。
当我致电mMediaRecorder.prepare()时，它会捕获异常并releaseMediaRecorder。
为什么我会收到错误？
E/MediaRecorderJNI: Application lost the surface
Error preparing MediaRecorder: invalid preview surface