import org.fourthline.cling.support.renderingcontrol.callback.GetVolume; //导入依赖的package包/类
public static void getVolume(final Handler handler) {
    Device device = SystemManager.getInstance().getSelectedDevice();
    //Check selected device
    if (device == null) return;

    Service rcService = device.findService(SystemManager.RENDERING_CONTROL_SERVICE);
    if (rcService != null) {
        ControlPoint cp = SystemManager.getInstance().getControlPoint();
        cp.execute(new GetVolume(rcService) {

            @Override
            public void received(ActionInvocation actionInvocation, int currentVolume) {
                //Send currentVolume to handler.
                Log.i(TAG, "GetVolume:" + currentVolume);
                Message msg = Message.obtain(handler, NowplayingFragment.GET_VOLUME_ACTION, currentVolume, 0);
                msg.sendToTarget();
            }

            @Override
            public void failure(ActionInvocation invocation, UpnpResponse operation, String defaultMsg) {
                Log.e(TAG, "GetVolume failed");
            }
        });
    }
}