Assuming that you want the jpeg saved, you don't need raw callback, so change the call to takePicture() from:
mCamera.takePicture(null, mPicture, mPicture);
to
mCamera.takePicture(null, null, mPicture);
in your onTouchEvent(). This will use jpeg picture callback.
Calling takePicture() also causes the preview to stop, so you might want to call startPreview() again in your onPictureTaken() callback, if you want to take more pictures or have a preview restarted.
Also, in your onTouchEvent(), you might be getting multiple events, so filter for the one that works for you:
@Override
public boolean onTouchEvent(MotionEvent event) {
Toast.makeText(context, "Picture taken", Toast.LENGTH_SHORT).show();
//System.gc(); tried this because it was suggested in a stackoverflow question but it didn't help.
switch(event.getAction()) {
case MotionEvent.ACTION_DOWN:
// A pressed gesture has started, the motion contains the initial starting location
break;
case MotionEvent.ACTION_UP:
// A pressed gesture has finished, the motion contains the final release location
// as well as any intermediate points since the last down or move event.
mCamera.takePicture(null, mPicture, mPicture);
break;
default:
break;
}
return true; //processed
}
If you place takePicture() in ACTION_DOWN, it will be called as soon as you touch the screen, whereas when in ACTION_UP, it will happen when you remove finger. See which one works for you.