mCamera
seems to be null
after this line:
mCamera = Camera.open();
According to Android Camera Reference:
If the device does not have a back-facing camera, this returns null.
In case you don't have a back camera you need to see the id of any cameras that are available.
Call Camera.getNumberOfCameras() and then pass a valid camera id into Camera.open(id)
To find more information about a specific camera,
call Camera.getCameraInfo()
where you can check the fields to determine what kind of camera it is