怎么调用AIDL 2

@Override
    protected void onDestroy() {
        if (mIsBound) {
            // If we have received the service, and hence registered with
            // it, then now is the time to unregister.
            if (mService != null) {
                try {
                    mService.unregisterCallback(mPTTServiceListener.callback);
                } catch (RemoteException e) {
                    // There is nothing special we need to do if the service
                    // has crashed.
                }
            }
            
            Log.d(TAG, "onDestroy()");
            // Detach our existing connection.
            unbindService(mConnection);
            mIsBound = false;
        }
    	super.onDestroy();
    }
    
    // maintain connection with PTTService
    private IPTTService mService = null;
    private ServiceConnection mConnection = new ServiceConnection() {
        public void onServiceConnected(ComponentName className,
                IBinder service) {
        	Log.d(TAG, "onServiceConnected");
            mService = IPTTService.Stub.asInterface(service);
            try{
            	mService.registerCallback(mPTTServiceListener.callback);
            }catch(RemoteException e){
            	e.printStackTrace();
            }
            
            mIsBound = true;
            
            try {
                if(mService.getServiceState() != SERVICE_STATE_NoneService){
                	mTestButton.setEnabled(true);
                	Log.d(TAG, "ServiceState = " + mService.getServiceState());
                }
			} catch (RemoteException e) {
				// TODO: handle exception
			}
            
            //Toast.makeText(MainActivity.this, "connected",Toast.LENGTH_SHORT).show();
        }

        public void onServiceDisconnected(ComponentName className) {
        	Log.d(TAG, "onServiceDisconnected");
            mService = null;
            mTestButton.setEnabled(false);
        }
    };
    
    // listener for PTT service
    PTTServiceListener mPTTServiceListener = new PTTServiceListener(){
    	@Override
    	void onPTTServiceNotification(Bundle data) {
    		
    	};
    	
    	@Override
    	void onPTTServiceError(String strMsg) {
    		Toast.makeText(MainActivity.this, strMsg, Toast.LENGTH_SHORT).show();
    	};
    };
    
}