switch back/front camera on fly

Question

If I use only CAMERA_FACING_BACK or CAMERA_FACING_FRONT all works fine.

I have trouble with switch from CAMERA_FACING_BACK to

Answer 1

Use this code:

if (mCamera != null) {
      mCamera.stopPreview();                  
      mCamera.release();
      mCamera = null;
}

//swap the id of the camera to be used
if (currentCameraId == Camera.CameraInfo.CAMERA_FACING_BACK)
  currentCameraId = Camera.CameraInfo.CAMERA_FACING_FRONT;
else 
  currentCameraId = Camera.CameraInfo.CAMERA_FACING_BACK;         

try {                
       mCamera = Camera.open(currentCameraId);   

       mCamera.setDisplayOrientation(90);

       mCamera.setPreviewDisplay(surfaceHolder);               

       mCamera.startPreview();

     } 
catch (Exception e) { e.printStackTrace(); } 

Answer 2

In onCreate() of my activity I add the following onClick listener to a button overlayed on my Preview SurfaceView (there are numerous example on the web for previewing):

ImageButton useOtherCamera = (ImageButton) findViewById(R.id.useOtherCamera);
//if phone has only one camera, hide "switch camera" button
if(Camera.getNumberOfCameras() == 1){
    useOtherCamera.setVisibility(View.INVISIBLE);
}
else {
    useOtherCamera.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
    if (inPreview) {
        camera.stopPreview();
    }
    //NB: if you don't release the current camera before switching, you app will crash
    camera.release();

    //swap the id of the camera to be used
    if(currentCameraId == Camera.CameraInfo.CAMERA_FACING_BACK){
        currentCameraId = Camera.CameraInfo.CAMERA_FACING_FRONT;
    }
    else {
        currentCameraId = Camera.CameraInfo.CAMERA_FACING_BACK;
    }
    camera = Camera.open(currentCameraId);
    //Code snippet for this method from somewhere on android developers, i forget where
    setCameraDisplayOrientation(CameraActivity.this, currentCameraId, camera);
    try {
        //this step is critical or preview on new camera will no know where to render to
        camera.setPreviewDisplay(previewHolder);
    } catch (IOException e) {
        e.printStackTrace();
    }
    camera.startPreview();
}

On my test device the back camera has an ID of 0 and the front has an id of 1. I suggest using Camera.CameraInfo static variables for your camera id's rather than hard-coding values. I am sure that will only cause issues on other devices.

Answer 3

I removed and re-added SurfaceView in my layout and so it worked.

public void switchCamera(int cameraType)
{
    if(context.getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA_FRONT))
    {
        if(Camera.getNumberOfCameras() > cameraType)
        {
            // Set selected camera
            this.cameraType = cameraType;
        }
        else
        {
            // Set default camera (Rear)
            this.cameraType = Camera.CameraInfo.CAMERA_FACING_BACK;
        }

        if(mCamera != null)
        {
            // Destroy previuos Holder
            surfaceDestroyed(holder);
            holder.removeCallback(this);

            // Remove and re-Add SurfaceView
            ViewGroup rootLayout = (ViewGroup) surface.getParent();
            rootLayout.removeView(surface);
            surface = new SurfaceView(context);
            holder = surface.getHolder();
            holder.addCallback(this);
            rootLayout.addView(surface, new ViewGroup.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT));
        }
    }
}

Answer 4

I have to remove the surface preview before adding a new one:

if (mPreview != null) {
        mPreview.surfaceDestroyed(mPreview.getHolder());
        mPreview.getHolder().removeCallback(mPreview);
        mPreview.destroyDrawingCache();
        FrameLayout preview = (FrameLayout) view.findViewById(R.id.camera_frame);
        preview.removeView(mPreview);
        mPreview.mCamera = null;
        mPreview = null;

    }

//then add your preview

Answer 5

I restart Activity with cameraId = 2 and this is working.