Camera preview not working

Question

I'm in trouble with camera preview. But first, here's the flow of my app:

1. Show Camera preview for video recording (works fine)
2. When video recording stops (user presses stop), play the recorded video (works fine)
3. on Recorded video completion, start camera preview (not working)

I can't figure it out why it's not working, there's no error returned in Logcat.

Anyone have an idea/suggestions for this preview to work?

Edits: When I pressed the hardware Home button then launch the app back, the camera preview works again.

Here's my code:

main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    ...>

    <VideoView android:id="@+id/videoView1" 
        android:layout_height="fill_parent" android:layout_width="fill_parent" android:layout_weight=".5"/>


    <RelativeLayout android:id="@+id/surfaceViewWrapper" android:layout_height="fill_parent" android:layout_width="fill_parent" android:layout_weight=".5">
        <com.sample.video.CameraSurfaceView
            android:id="@+id/cameraView" android:layout_width="fill_parent" android:layout_height="fill_parent" android:background="#00ff00"
            />
    </RelativeLayout>
</LinearLayout>

CameraSurfaceView.java

public class CameraSurfaceView extends ViewGroup  implements SurfaceHolder.Callback{
    ...
    private Camera mCamera;
    private MediaRecorder mMediaRecorder;
    private int frontCameraId;

    public CameraSurfaceView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }

    public CameraSurfaceView(Context context, AttributeSet attrs) {
        super(context, attrs);
        mSurfaceView = new SurfaceView(context);
        addView(mSurfaceView);

        mHolder = mSurfaceView.getHolder();
        mHolder.addCallback(this);
        mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);

        frontCameraId = 0;
    }

    //---Recording---
    public void startRecording(){
        mMediaRecorder.start();
    }

    public boolean prepareVideoRecorder() throws IOException{
        //Some code here from google, I didn't include in this post to make this not too long
        ...
    }

    public void stopRecording() {
        mMediaRecorder.stop();
    }

    public void releaseMediaRecorder(){
        if (mMediaRecorder != null) {
            mMediaRecorder.reset();   // clear recorder configuration
            mMediaRecorder.release(); // release the recorder object
            mMediaRecorder = null;
            mCamera.lock();           // lock camera for later use
        }
    }

    //###---Camera---
    public void releaseCamera(){
        //Some code here from google, I didn't include in this post to make this not too long
        ...
    }
    public void useFrontCamera(){
        int numberOfCameras = Camera.getNumberOfCameras();

        CameraInfo cameraInfo = new CameraInfo();
        for (int i = 0; i < numberOfCameras; i++) {
            Camera.getCameraInfo(i, cameraInfo);
            if (cameraInfo.facing == CameraInfo.CAMERA_FACING_FRONT) {
                frontCameraId = i;
            }
        }

        mCamera = Camera.open(frontCameraId);
        if (mCamera != null) {
            mSupportedPreviewSizes = mCamera.getParameters().getSupportedPreviewSizes();
            requestLayout();
        }
    }

    public void surfaceCreated(SurfaceHolder holder) {
        // The Surface has been created, acquire the camera and tell it where
        // to draw.
        try {
            if (mCamera != null) {
                mCamera.setPreviewDisplay(holder);
            }
        } catch (IOException exception) {
            Log.e(TAG, "IOException caused by setPreviewDisplay()", exception);
        }
    }

    public void surfaceDestroyed(SurfaceHolder holder) {
        // Surface will be destroyed when we return, so stop the preview.
        if (mCamera != null) {
            mCamera.stopPreview();
        }
    }

    public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
        // Now that the size is known, set up the camera parameters and begin
        // the preview.
        if (mCamera != null) {
            Camera.Parameters parameters = mCamera.getParameters();
            parameters.setPreviewSize(mPreviewSize.width, mPreviewSize.height);
            requestLayout();

            mCamera.setParameters(parameters);
            mCamera.startPreview();
        }

    }

    public void startPreview(){
       mCamera.startPreview();
    }

    public void setCamera(Camera camera){
        this.mCamera = camera;
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        //Some code here from google, I didn't include in this post to make this not too long
        ...
    }

    @Override
    protected void onLayout(boolean changed, int l, int t, int r, int b) {
        //Some code here from google, I didn't include in this post to make this not too long
        ...
    }

    private Size getOptimalPreviewSize(List<Size> sizes, int w, int h) {
        //Some code here from google, I didn't include in this post to make this not too long
        ...
    }
    }
    CameraPreview code: http://developer.android.com/resources/samples/ApiDemos/src/com/example/android/apis/graphics/CameraPreview.html

MainActivity.java

public class MainActivity extends Activity{
    CameraSurfaceView cameraSurfaceView;
    private boolean isRecording = false;
    private VideoView mVideoView;
    MediaPlayer mpPlayer;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        cameraSurfaceView = (CameraSurfaceView)findViewById(R.id.cameraView);
        mVideoView = (VideoView)findViewById(R.id.videoView1);
    }

    @Override
    protected void onResume() {
        super.onResume();
        cameraSurfaceView.useFrontCamera();
    }

    @Override
    protected void onPause() {
        super.onPause();
        cameraSurfaceView.releaseMediaRecorder();
        cameraSurfaceView.releaseCamera();
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu){
        menu.add(0, 0, 0, "Start Recording");
        menu.add(0, 1, 0, "Stop Recording");
        menu.add(0, 2, 0, "Play Recording");
        return super.onCreateOptionsMenu(menu);
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item){
        switch (item.getItemId())
        {
            case 0:
                if(isRecording){
                    // stop recording and release camera
                    cameraSurfaceView.stopRecording();  // stop the recording
                    cameraSurfaceView.releaseMediaRecorder(); // release the MediaRecorder object

                    isRecording = false;
                }else{
                    try {
                        // initialize video camera
                        if (cameraSurfaceView.prepareVideoRecorder()) {


                            // Camera is available and unlocked, MediaRecorder is prepared,
                            // now you can start recording
                            cameraSurfaceView.startRecording();

                            // inform the user that recording has started
                            isRecording = true;
                            Toast.makeText(getBaseContext(), "Recording Start.", Toast.LENGTH_SHORT).show();
                        } else {
                            // prepare didn't work, release the camera
                            cameraSurfaceView.releaseMediaRecorder();
                        }
                    }catch (Exception e) {
                        String message = e.getMessage();
                        Log.i(null, "Problem Start"+message);
                        cameraSurfaceView.releaseMediaRecorder();
                    }
                }

                break;
            case 1: 
                if(isRecording){
                    // stop recording and release camera
                    cameraSurfaceView.stopRecording();  // stop the recording
                    cameraSurfaceView.releaseMediaRecorder(); // release the MediaRecorder object

                    // inform the user that recording has stopped
                    isRecording = false;
                }
                break;
            case 2:
                //play video
                cameraSurfaceView.releaseMediaRecorder();
                cameraSurfaceView.releaseCamera();

                if (mVideoView.getVisibility() == View.INVISIBLE) {
                    mVideoView.setVisibility(View.VISIBLE);
                }


                if(cameraSurfaceView.getVisibility() == View.VISIBLE)
                    cameraSurfaceView.setVisibility(View.INVISIBLE);


                try {
                    mpPlayer = new MediaPlayer();
                    mpPlayer.setDisplay(mVideoView.getHolder());
                    mpPlayer.setDataSource(MainActivity2.this, Uri.parse(Environment.getExternalStorageDirectory() + "/Sample Video Recording/sample.mp4"));
                    mpPlayer.setOnCompletionListener(onVideoComplete);
                    mpPlayer.setOnErrorListener(onErrorMediaPlayer);
                    mpPlayer.prepare();
                    mpPlayer.start();
                } catch (IllegalArgumentException e) {e.printStackTrace();
                } catch (SecurityException e) {e.printStackTrace();
                } catch (IllegalStateException e) {e.printStackTrace();
                } catch (IOException e) {e.printStackTrace();
                }
                break;
            default:
                break;
        }
        return super.onOptionsItemSelected(item);
    }

    public MediaPlayer.OnErrorListener onErrorMediaPlayer = new MediaPlayer.OnErrorListener(){
        @Override
        public boolean onError(MediaPlayer mp, int what, int extra) {
            mp.reset();
            return false;
        }

    };
    public MediaPlayer.OnPreparedListener onNarrPreparedListener = new MediaPlayer.OnPreparedListener(){
        @Override
        public void onPrepared(MediaPlayer mp) {

        }
    };

    private MediaPlayer.OnCompletionListener onVideoComplete = new MediaPlayer.OnCompletionListener() {
        @Override
        public void onCompletion(MediaPlayer mp) {
            mpPlayer.stop();
            mpPlayer.release();

            if (mVideoView.getVisibility() == View.VISIBLE) {
                mVideoView.setVisibility(View.INVISIBLE);
            }

            if(cameraSurfaceView != null){
            cameraSurfaceView.releaseMediaRecorder();
            cameraSurfaceView.releaseCamera();
            }

            if(cameraSurfaceView.getVisibility() == View.INVISIBLE)
                cameraSurfaceView.setVisibility(View.VISIBLE);

            cameraSurfaceView.useFrontCamera();
            cameraSurfaceView.startPreview();
        }
    };
}

Manifest:

...
    <uses-permission android:name="android.permission.CAMERA"/>
    <uses-permission android:name="android.permission.RECORD_AUDIO"/>
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

    <uses-feature android:name="android.hardware.camera" android:required="false"/>
...

Thanks ahead guys.

Answer 1

calling cameraProvider.unbindAll() resolves this

Answer 2

You have to unlock the camera before creating MediaRecorder. And lock it before releasing it.

Try this code, it will work Have fun...

if(mCamera == null) 

{
 mCamera = Camera.open();
 mCamera.unlock();
}


if(mMediaRecorder == null)
    mMediaRecorder = new MediaRecorder();


mMediaRecorder.setPreviewDisplay(surface);
mMediaRecorder.setCamera(mCamera);
mMediaRecorder.setVideoSource(MediaRecorder.VideoSource.CAMERA);