我有一个Android视频捕获应用，但在三星设备中，我收到以下错误。
我试图从mRecordButton.click中移除startPreview（）（这是实际停止录制的按钮），但没有成功。
我可以做些什么？
错误：
Fatal Exception: java.lang.NullPointerException: Attempt to invoke virtual method 'android.hardware.camera2.CaptureRequest$Builder android.hardware.camera2.CameraDevice.createCaptureRequest(int)' on a null object reference
at com.jobconvo.www.newjcapp.CameraActivity.startPreview(CameraActivity.java:427)
at com.jobconvo.www.newjcapp.CameraActivity.access$800(CameraActivity.java:53)
at com.jobconvo.www.newjcapp.CameraActivity$5.onClick(CameraActivity.java:268)
at android.view.View.performClick(View.java:5716)
at android.widget.TextView.performClick(TextView.java:10926)
at android.view.View$PerformClick.run(View.java:22596)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:7325)
at java.lang.reflect.Method.invoke(Method.java)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120)
我的相机活动代码：
public class CameraActivity extends AppCompatActivity {
private static final int STATE_PREVIEW = 0;
private static final int STATE_WAIT_LOCK = 1;
private int mCaptureState = STATE_PREVIEW;
private TextureView mTextureView;
private TextureView.SurfaceTextureListener mSurfaceTextureListener = new TextureView.SurfaceTextureListener() {
@Override
public void onSurfaceTextureAvailable(SurfaceTexture surface, int width, int height) {
setupCamera(width, height);
try {
connectCamera();
} catch (CameraAccessException e) {
e.printStackTrace();
}
}
@Override
public void onSurfaceTextureSizeChanged(SurfaceTexture surface, int width, int height) {
}
@Override
public boolean onSurfaceTextureDestroyed(SurfaceTexture surface) {
return false;
}
@Override
public void onSurfaceTextureUpdated(SurfaceTexture surface) {
}
};
private CameraDevice mCameraDevice;
private CameraDevice.StateCallback mCameraDeviceStateCallback = new CameraDevice.StateCallback() {
@Override
public void onOpened(CameraDevice camera) {
mCameraDevice = camera;
mMediaRecorder = new MediaRecorder();
if (mIsRecording) {
try {
createVideoFileName();
} catch (IOException e) {
e.printStackTrace();
}
startRecord();
mMediaRecorder.start();
runOnUiThread(new Runnable() {
@Override
public void run() {
countDownTimer.start();
}
});
} else {
startPreview();
}
}
@Override
public void onDisconnected(CameraDevice camera) {
camera.close();
mCameraDevice = null;
}
@Override
public void onError(CameraDevice camera, int error) {
camera.close();
mCameraDevice = null;
}
};
private HandlerThread mBackgroundHandlerThread;
private Handler mBackgroundHandler;
private String mCameraId;
private Size mPreviewSize;
private Size mVideoSize;
private MediaRecorder mMediaRecorder;
private int mTotalRotation;
private CameraCaptureSession mPreviewCaptureSession;
private CameraCaptureSession.CaptureCallback mPreviewCaptureCallback = new
CameraCaptureSession.CaptureCallback() {
private void process(CaptureResult captureResult) {
switch (mCaptureState) {
case STATE_PREVIEW:
// Do nothing
break;
case STATE_WAIT_LOCK:
mCaptureState = STATE_PREVIEW;
Integer afState = captureResult.get(CaptureResult.CONTROL_AF_STATE);
if (afState == CaptureResult.CONTROL_AF_STATE_FOCUSED_LOCKED ||
afState == CaptureResult.CONTROL_AF_STATE_NOT_FOCUSED_LOCKED) {
Toast.makeText(getApplicationContext(), "AF Locked!", Toast.LENGTH_SHORT).show();
}
break;
}
}
@Override
public void onCaptureCompleted(CameraCaptureSession session, CaptureRequest request, TotalCaptureResult result) {
super.onCaptureCompleted(session, request, result);
process(result);
}
};
private CameraCaptureSession mRecordCaptureSession;
private CameraCaptureSession.CaptureCallback mRecordCaptureCallback = new
CameraCaptureSession.CaptureCallback() {
private void process(CaptureResult captureResult) {
switch (mCaptureState) {
case STATE_PREVIEW:
// Do nothing
break;
case STATE_WAIT_LOCK:
mCaptureState = STATE_PREVIEW;
Integer afState = captureResult.get(CaptureResult.CONTROL_AF_STATE);
if (afState == CaptureResult.CONTROL_AF_STATE_FOCUSED_LOCKED ||
afState == CaptureResult.CONTROL_AF_STATE_NOT_FOCUSED_LOCKED) {
Toast.makeText(getApplicationContext(), "AF Locked!", Toast.LENGTH_SHORT).show();
}
break;
}
}
@Override
public void onCaptureCompleted(CameraCaptureSession session, CaptureRequest request, TotalCaptureResult result) {
super.onCaptureCompleted(session, request, result);
process(result);
}
};
private CaptureRequest.Builder mCaptureRequestBuilder;
private Button mRecordButton;
private boolean mIsRecording = false;
private boolean mIsTimelapse = false;
private File mVideoFolder;
private String mVideoFileName;
private MainModel mainModel;
private static SparseIntArray ORIENTATIONS = new SparseIntArray();
static {
ORIENTATIONS.append(Surface.ROTATION_0, 0);
ORIENTATIONS.append(Surface.ROTATION_90, 90);
ORIENTATIONS.append(Surface.ROTATION_180, 180);
ORIENTATIONS.append(Surface.ROTATION_270, 270);
}
private static class CompareSizeByArea implements Comparator<Size> {
@Override
public int compare(Size lhs, Size rhs) {
return Long.signum((long) (lhs.getWidth() * lhs.getHeight()) -
(long) (rhs.getWidth() * rhs.getHeight()));
}
}
int questionId;
int questionAnswerTime;
String interviewId;
TextView showTimer;
private static String formatTime(int elapsed) {
int ss = elapsed % 60;
elapsed /= 60;
int min = elapsed % 60;
elapsed /= 60;
int hh = elapsed % 24;
return strzero(min) + ":" + strzero(ss);
}
private static String strzero(int n) {
if (n < 10)
return "0" + String.valueOf(n);
return String.valueOf(n);
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_camera);
Fabric.with(this, new Crashlytics());
mainModel = (MainModel) getIntent().getSerializableExtra("serialized_data");
interviewId = mainModel.getInterviewID();
final ScriptQuestion getQuestion = mainModel.questions.get(0);
questionId = getQuestion.getQuestionId();
questionAnswerTime = getQuestion.getQuestionAnswerTime();
showTimer = (TextView) findViewById(R.id.chronometer);
mTextureView = (TextureView) findViewById(R.id.textureView);
mRecordButton = (Button) findViewById(R.id.videoButton);
mRecordButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
countDownTimer.cancel();
mIsRecording = false;
mIsTimelapse = false;
// Starting the preview prior to stopping recording which should hopefully
// resolve issues being seen in Samsung devices.
startPreview();
mMediaRecorder.stop();
mMediaRecorder.reset();
Intent mediaStoreUpdateIntent = new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE);
mediaStoreUpdateIntent.setData(Uri.fromFile(new File(mVideoFileName)));
sendBroadcast(mediaStoreUpdateIntent);
goNext();
}
});
}
private CountDownTimer countDownTimer = new CountDownTimer(600000, 1000) {
public void onTick(long millisUntilFinished) {
// 600000 = 10 minutes
int restTime = questionAnswerTime * 60 - (600 - ((int) (millisUntilFinished) / 1000));
String tmpRest = formatTime(restTime);
showTimer.setText(tmpRest);
if (restTime < 1) {
onFinish();
}
}
public void onFinish() {
mRecordButton.performClick();
}
};
@Override
protected void onResume() {
super.onResume();
startBackgroundThread();
if (mTextureView.isAvailable()) {
setupCamera(mTextureView.getWidth(), mTextureView.getHeight());
} else {
mTextureView.setSurfaceTextureListener(mSurfaceTextureListener);
}
mIsRecording = true;
}
@Override
protected void onPause() {
closeCamera();
stopBackgroundThread();
super.onPause();
}
@Override
public void onWindowFocusChanged(boolean hasFocus) {
super.onWindowFocusChanged(hasFocus);
View decorView = getWindow().getDecorView();
if (hasFocus) {
decorView.setSystemUiVisibility(View.SYSTEM_UI_FLAG_LAYOUT_STABLE
| View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY
| View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN
| View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
| View.SYSTEM_UI_FLAG_FULLSCREEN
| View.SYSTEM_UI_FLAG_HIDE_NAVIGATION);
}
}
private void setupCamera(int width, int height) {
CameraManager cameraManager = (CameraManager) getSystemService(Context.CAMERA_SERVICE);
try {
for (String cameraId : cameraManager.getCameraIdList()) {
CameraCharacteristics cameraCharacteristics = cameraManager.getCameraCharacteristics(cameraId);
if (cameraCharacteristics.get(CameraCharacteristics.LENS_FACING) ==
CameraCharacteristics.LENS_FACING_BACK) {
continue;
}
StreamConfigurationMap map = cameraCharacteristics.get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP);
int deviceOrientation = getWindowManager().getDefaultDisplay().getRotation();
mTotalRotation = sensorToDeviceRotation(cameraCharacteristics, deviceOrientation);
boolean swapRotation = mTotalRotation == 90 || mTotalRotation == 270;
int rotatedWidth = width;
int rotatedHeight = height;
if (swapRotation) {
rotatedWidth = height;
rotatedHeight = width;
}
mPreviewSize = chooseOptimalSize(map.getOutputSizes(SurfaceTexture.class), rotatedWidth, rotatedHeight);
mVideoSize = chooseOptimalSize(map.getOutputSizes(MediaRecorder.class), rotatedWidth, rotatedHeight);
mCameraId = cameraId;
return;
}
} catch (CameraAccessException e) {
e.printStackTrace();
}
}
private void connectCamera() throws CameraAccessException {
CameraManager cameraManager = (CameraManager) getSystemService(Context.CAMERA_SERVICE);
if (ActivityCompat.checkSelfPermission(this, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
return;
}
cameraManager.openCamera(mCameraId, mCameraDeviceStateCallback, mBackgroundHandler);
}
private void startRecord() {
try {
if(mIsRecording) {
setupMediaRecorder();
} else if(mIsTimelapse) {
setupTimelapse();
}
SurfaceTexture surfaceTexture = mTextureView.getSurfaceTexture();
surfaceTexture.setDefaultBufferSize(mPreviewSize.getWidth(), mPreviewSize.getHeight());
Surface previewSurface = new Surface(surfaceTexture);
Surface recordSurface = mMediaRecorder.getSurface();
mCaptureRequestBuilder = mCameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_RECORD);
mCaptureRequestBuilder.addTarget(previewSurface);
mCaptureRequestBuilder.addTarget(recordSurface);
mCameraDevice.createCaptureSession(Arrays.asList(previewSurface, recordSurface),
new CameraCaptureSession.StateCallback() {
@Override
public void onConfigured(CameraCaptureSession session) {
mRecordCaptureSession = session;
try {
mRecordCaptureSession.setRepeatingRequest(
mCaptureRequestBuilder.build(), null, null
);
} catch (CameraAccessException e) {
e.printStackTrace();
}
}
@Override
public void onConfigureFailed(CameraCaptureSession session) {
//Log.d(TAG, "onConfigureFailed: startRecord");
}
}, null);
} catch (Exception e) {
e.printStackTrace();
}
}
private void startPreview() {
SurfaceTexture surfaceTexture = mTextureView.getSurfaceTexture();
assert surfaceTexture != null;
surfaceTexture.setDefaultBufferSize(mPreviewSize.getWidth(), mPreviewSize.getHeight());
Surface previewSurface = new Surface(surfaceTexture);
try {
mCaptureRequestBuilder = mCameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW);
mCaptureRequestBuilder.addTarget(previewSurface);
mCameraDevice.createCaptureSession(Arrays.asList(previewSurface),
new CameraCaptureSession.StateCallback() {
@Override
public void onConfigured(CameraCaptureSession session) {
//Log.d(TAG, "onConfigured: startPreview");
mPreviewCaptureSession = session;
try {
mPreviewCaptureSession.setRepeatingRequest(mCaptureRequestBuilder.build(),
null, mBackgroundHandler);
} catch (CameraAccessException e) {
e.printStackTrace();
}
}
@Override
public void onConfigureFailed(CameraCaptureSession session) {
//Log.d(TAG, "onConfigureFailed: startPreview");
}
}, null);
} catch (CameraAccessException e) {
e.printStackTrace();
}
}
private void closeCamera() {
if(mCameraDevice != null) {
mCameraDevice.close();
mCameraDevice = null;
}
if(mMediaRecorder != null) {
mMediaRecorder.release();
mMediaRecorder = null;
}
}
private void startBackgroundThread() {
mBackgroundHandlerThread = new HandlerThread("Camera2VideoImage");
mBackgroundHandlerThread.start();
mBackgroundHandler = new Handler(mBackgroundHandlerThread.getLooper());
}
private void stopBackgroundThread() {
mBackgroundHandlerThread.quitSafely();
try {
mBackgroundHandlerThread.join();
mBackgroundHandlerThread = null;
mBackgroundHandler = null;
} catch (InterruptedException e) {
e.printStackTrace();
}
}
private static int sensorToDeviceRotation(CameraCharacteristics cameraCharacteristics, int deviceOrientation) {
int sensorOrienatation = cameraCharacteristics.get(CameraCharacteristics.SENSOR_ORIENTATION);
deviceOrientation = ORIENTATIONS.get(deviceOrientation);
return (sensorOrienatation + deviceOrientation + 360) % 360;
}
private static Size chooseOptimalSize(Size[] choices, int width, int height) {
List<Size> bigEnough = new ArrayList<Size>();
for(Size option : choices) {
if(option.getHeight() == option.getWidth() * height / width &&
option.getWidth() >= width && option.getHeight() >= height) {
bigEnough.add(option);
}
}
if(bigEnough.size() > 0) {
return Collections.min(bigEnough, new CompareSizeByArea());
} else {
return choices[0];
}
}
private File createVideoFileName() throws IOException {
File mediaStorageDir = new File(Environment.getExternalStorageDirectory(), "JobConvoVideos");
mVideoFolder = new File(mediaStorageDir, "JobConvoVideos");
if(!mVideoFolder.exists()) {
mVideoFolder.mkdirs();
}
String prepend = "android-" + interviewId + "-" + String.valueOf(questionId) + ".mp4";
File videoFile = new File(mediaStorageDir.getPath() + File.separator + prepend);
mVideoFileName = videoFile.getAbsolutePath();
return videoFile;
}
public static File getOutputMediaFile(String _interviewId, int qstId, Context _context){
String idInterview = _interviewId;
idInterview = "android-" + idInterview + "-" + String.valueOf(qstId) + ".mp4";
File mediaStorageDir = new File(Environment.getExternalStorageDirectory(), "JobConvoVideos");
_context.getExternalFilesDir("JobConvoVideos");
File f = new File(mediaStorageDir.getPath() + File.separator + idInterview);
return f;
}
private void setupMediaRecorder() throws IOException {
mMediaRecorder.setVideoSource(MediaRecorder.VideoSource.SURFACE);
mMediaRecorder.setAudioSource(MediaRecorder.AudioSource.DEFAULT);
mMediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);
mMediaRecorder.setOutputFile(mVideoFileName);
mMediaRecorder.setVideoEncodingBitRate(1000000);
mMediaRecorder.setVideoFrameRate(30);
mMediaRecorder.setVideoSize(mVideoSize.getWidth(), mVideoSize.getHeight());
mMediaRecorder.setVideoEncoder(MediaRecorder.VideoEncoder.MPEG_4_SP);
mMediaRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
mMediaRecorder.setOrientationHint(mTotalRotation);
mMediaRecorder.getMaxAmplitude();
mMediaRecorder.prepare();
}
private void setupTimelapse() throws IOException {
mMediaRecorder.setVideoSource(MediaRecorder.VideoSource.SURFACE);
mMediaRecorder.setProfile(CamcorderProfile.get(CamcorderProfile.QUALITY_QVGA));
mMediaRecorder.setOutputFile(mVideoFileName);
mMediaRecorder.setCaptureRate(2);
mMediaRecorder.setOrientationHint(mTotalRotation);
mMediaRecorder.prepare();
}
private void goNext() {
finish();
Intent goUpload = new Intent(this, VideoUploadActivity.class);
goUpload.putExtra("serialized_data", mainModel);
startActivity(goUpload);
}
@Override
public void onBackPressed() {
Toast.makeText(getApplicationContext(), R.string.getBack, Toast.LENGTH_LONG).show();
}
}
答案 0 :(得分：0)
I added a try catch here in which the app has shown a great improvement. Nonetheless it still crashes sometimes. Not very often.
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