protected void initPowerShutter(ComboPreferences prefs) {
        prefs.setLocalId(getApplicationContext(), 0);
        String val = prefs.getString(CameraSettings.KEY_POWER_SHUTTER,
                getResources().getString(R.string.pref_camera_power_shutter_default));
        mPowerShutter = val.equals(CameraSettings.VALUE_ON);
        if (mPowerShutter && mShowCameraAppView) {
            getWindow().addFlags(WindowManager.LayoutParams.PREVENT_POWER_KEY);
        } else {
            getWindow().clearFlags(WindowManager.LayoutParams.PREVENT_POWER_KEY);
        }
    }