How to recover camera preview from sleep?

Question

I have an application that shows camera preview and I would like the user to be able to put the phone to sleep and then wake it so that my application will recover correctly

Answer 1

I was having the same issue and here's why:

The onPause method does not recycle the CameraPreview class I made (that implements SurfaceView Callbacks). Instead of trying to re instantiate that entire object itself, i merely updated the camera object reference i was passing it to be either

null

or

cameraPreview.setCamera(mCamera);

I called a getCameraInstance method to re initialize the camera, then passed it into the preivew object.

Now the problem is here:

private void initializeCameraView(){

    RelativeLayout preview = (RelativeLayout)rootView.findViewById(R.id.camera_preview);

    preview.addView(cameraPreview);
}

in onResume, i called this method to re initialize the cameraPreview object. However, it was freezing because I was trying to add another cameraPreview to the preview view. This was my fix, plain and simple. If it already exists, remove it, then put it right back in. Hope this helps!

private void initializeCameraView(){

    RelativeLayout preview = (RelativeLayout)rootView.findViewById(R.id.camera_preview);
    //removes the problem with the camera freezing onResume
    if(cameraPreview != null) {
        preview.removeView(cameraPreview);
    }
    preview.addView(cameraPreview);
}

Answer 2

One solution maybe setting the surfaceview to invisible and visible again in onResume(), this makes the surfaceview destroy and recreates.