当我在 jellybean 上的 archos 平板电脑上按下后退按钮时，Android Camera 表面 View 相机重新创建

Question

在我的代码中，我在单击按钮时进行了摄像头预览和视频录制，因此我的代码可以很好地进行录制和预览。

但是当我按下后退按钮时，在调用 surfaceview destroy 方法之后调用 surfaceview 创建和 surface view change 方法，所以我必须再次按下 back 按钮，此时它直接调用 surface destroy(第二次 surface create 和 surface change不被调用)

这是我的代码，任何人都可以帮助我吗？

public class VideoCapture extends Activity implements  SurfaceHolder.Callback {

public static final String LOGTAG = "VIDEOCAPTURE";
private static final int SELECT_PHOTO = 100;
private MediaRecorder recorder;
private SurfaceHolder holder;
private CamcorderProfile camcorderProfile;
private Camera camera;        

boolean recording = false;
boolean usecamera = true;
boolean previewRunning = false;
Button recorderButton,selectVideo;
long init,now,time;
Handler handler;
Runnable updater;
SimpleDateFormat df;
Camera.Parameters parameters;
String timeString, timeStamp,selectedVideoPath;


@Override
public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        requestWindowFeature(Window.FEATURE_NO_TITLE);
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
                        WindowManager.LayoutParams.FLAG_FULLSCREEN);
        setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
        setContentView(R.layout.main);
         handler = new Handler();
       df = new SimpleDateFormat("mm:ss");

        camcorderProfile = CamcorderProfile.get(CamcorderProfile.QUALITY_HIGH);
        recorderButton = (Button)findViewById(R.id.button);
        selectVideo = (Button)findViewById(R.id.videoselect);

        final TextView timerText = (TextView)findViewById(R.id.time);
        File dir = new File(Environment.getExternalStoragePublicDirectory(
                Environment.DIRECTORY_DCIM), "/Filme");
        if (!dir.exists()) {
            dir.mkdirs();
        }

        // Animation for blinking red dot while recording
        SurfaceView cameraView = (SurfaceView) findViewById(R.id.CameraView);

        holder = cameraView.getHolder();
        holder.addCallback(this);
        holder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);      

        cameraView.setClickable(true);


        cameraView.setOnClickListener(new OnClickListener(){
            @Override
            public void onClick(View v) {
                camera.autoFocus(new AutoFocusCallback(){
                    @Override
                    public void onAutoFocus(boolean arg0, Camera arg1) {
                        //camera.takePicture(shutterCallback, rawCallback, jpegCallback);
                    }
                });
            }
        });  

        selectVideo.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub

                  Intent photoPickerIntent = new Intent(Intent.ACTION_PICK);
                  photoPickerIntent.setType("video/*");

                  startActivityForResult(photoPickerIntent, SELECT_PHOTO);  
            }
        });

        recorderButton.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                 if (recording) {
                     recorderButton.setBackgroundResource(R.drawable.recordbutton_background_selector);
                        recorder.stop();
                        handler.removeCallbacks(updater); // stop handler


                     // to refresh media scan on storage 
                        sendBroadcast(new Intent(Intent.ACTION_MEDIA_MOUNTED, Uri.parse
                                ("file://" + Environment.getExternalStorageDirectory())));

                        String filepath =Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DCIM)+File.separator+"Filme"+File.separator+"Filme_"+timeStamp+".mp4";
                        Intent i = new Intent(getBaseContext(),VideoCutActivity.class);
                          i.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);

                          i.putExtra("path", filepath);
                          getBaseContext().startActivity(i);
                          finish();
                         /*
                        if (usecamera) {
                                try {
                                        camera.reconnect();
                                } catch (IOException e) {
                                        e.printStackTrace();

                                }
                        }                        
                      */
                        recording = false;
                        Log.v(LOGTAG, "Recording Stopped");
                        // Let's prepareRecorder so we can record again
                       // prepareRecorder();
                } else {
                    recorderButton.setBackgroundResource(R.drawable.stopbutton_background_selector);



                        recording = true;
                        prepareRecorder();
                     //   recorder.start();
                        Log.v(LOGTAG, "Recording Started");
                }
            }
        });

        // Recording timmer 
         updater = new Runnable() {
            @Override
            public void run() {

                    now=System.currentTimeMillis();
                    time=now-init;
                    timeString  = df.format(new Date(time));
                    timerText.setText(timeString);
                    handler.postDelayed(this, 30);

            }
        };

}
   @Override
  protected void onResume() {
       super.onResume();
  Log.e("onresume", "on resume");
    // Open the default i.e. the first rear facing camera. 
}



@Override
protected void onPause() {
    super.onPause();

    // Because the Camera object is a shared resource, it's very
    // important to release it when the activity is paused.
    if (recording) {
     recorder.stop();
        recording = false;
        recorder.release();
        camera.stopPreview();
        camera.setPreviewCallback(null);
        camera.release();
        camera = null;
}
else
{
    if (camera != null) {      
        previewRunning = false;
        camera.release();
        camera = null;
    }
}}


@Override
protected void onActivityResult(int requestCode, int resultCode, Intent imageReturnedIntent) { 
    super.onActivityResult(requestCode, resultCode, imageReturnedIntent); 

    switch(requestCode) { 
    case SELECT_PHOTO:
        if(resultCode == RESULT_OK){  
            Uri selectedImage = imageReturnedIntent.getData();
            selectedVideoPath  = getPath(selectedImage);

          Intent i = new Intent(getBaseContext(),VideoCutActivity.class);
          i.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);

          i.putExtra("path", selectedVideoPath);
          VideoCapture.this.startActivity(i);
          finish();

        }
    }
}

public String getPath(Uri uri) {
     String[] proj = { MediaStore.Images.Media.DATA };
        CursorLoader loader = new CursorLoader(getBaseContext(), uri, proj, null, null, null);
        Cursor cursor = loader.loadInBackground();
        int column_index = cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA);
        cursor.moveToFirst();
        return cursor.getString(column_index);
    }


private void prepareRecorder() {
recorder = new MediaRecorder();
        recorder.setPreviewDisplay(holder.getSurface());

        if (usecamera) {
                camera.unlock();
                recorder.setCamera(camera);
        }

        recorder.setAudioSource(MediaRecorder.AudioSource.DEFAULT);
        recorder.setVideoSource(MediaRecorder.VideoSource.DEFAULT);
        recorder.setProfile(camcorderProfile);


        timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
        recorder.setOutputFile(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DCIM)+File.separator+"Filme"+File.separator+"Filme_"+timeStamp+".mp4");
        Log.v(LOGTAG, "camcorderProfile");


        try {
                recorder.prepare();
                recorder.start();
                init = System.currentTimeMillis();
                handler.post(updater);

        } catch (IllegalStateException e) {
                e.printStackTrace();
                finish();
        } catch (IOException e) {
                e.printStackTrace();
                finish();
        }
}



public void surfaceCreated(SurfaceHolder holder) {
        Log.v(LOGTAG, "surfaceCreated");

        if (usecamera) {
                camera = Camera.open();
                parameters = camera.getParameters();
                try {
                    Log.i("Capture","surface created");
                     parameters.setFocusMode(Camera.Parameters.FOCUS_MODE_AUTO);
                     camera.setParameters(parameters);
                        camera.setPreviewDisplay(holder);
                        camera.startPreview();
                        previewRunning = true;
                }
                catch (IOException e) {
                        Log.e(LOGTAG,e.getMessage());
                        e.printStackTrace();
                }        
        }                

}


public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
        Log.v(LOGTAG, "surfaceChanged");

        if (!recording && usecamera) {

                if (previewRunning){
                    Log.e("Capture","preview is running");
                        camera.stopPreview();
                }

                try {
                    Log.e("Capture","inside try of surface changed");
                    parameters = camera.getParameters();
                    parameters.setFocusMode(Camera.Parameters.FOCUS_MODE_AUTO);
                    parameters.setPreviewSize(camcorderProfile.videoFrameWidth, camcorderProfile.videoFrameHeight);
                    parameters.setPreviewFrameRate(camcorderProfile.videoFrameRate);

                        camera.setParameters(parameters);
                        camera.setPreviewDisplay(holder);
                        camera.startPreview();
                        previewRunning = true;
                }
                catch (IOException e) {

                        Log.e(LOGTAG,e.getMessage());
                        e.printStackTrace();
                }        

               // prepareRecorder();        
        }
}


public void surfaceDestroyed(SurfaceHolder holder) {
        Log.v(LOGTAG, "surfaceDestroyed");

        if (camera != null) {
            camera.stopPreview();
        }

        if (recording) {
            try{
            Log.e("Capture","inside recording  of surface destory");
                recorder.stop();
                recording = false;
                recorder.release();
                camera.stopPreview();
                camera.setPreviewCallback(null);
                camera.release();
                camera = null;
            }
            catch (RuntimeException e) {
                Log.d("surface destroyed", "Problem in surfaceDestroyed"); 
                e.printStackTrace();
            } 
        }

Answer 1

基于调试/聊天讨论:

• 第一次返回时，现有的 Camera Activity 被销毁并创建了另一个。使用以下内容跟踪返回堆栈中的更改:

  adb shell dumpsys Activity | grep -i 运行

• 不需要新的任务，所以这是无用的:i.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);

  显然，使用 i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP) 有帮助!

但我不确定为什么这会有所帮助。 (特别是，因为 IIUC，使用 *CLEAR_TOP，将使用堆栈上 Activity 的现有实例(使用 onNewIntent)，但在这里(根据 dumpsys 的输出，创建了一个新 Activity :|)。但它适用于爱可视。