如何在android中创建一个我可以从服务器接收消息的简单的webclient客户端？

Question

public class CsmConnection extends AppCompatActivity {

    class EmptyClient extends WebSocketClient {

        public EmptyClient(URI serverUri, Draft draft) {
            super(serverUri, draft);
        }

        public EmptyClient(URI serverURI) {
            super(serverURI);
        }

        @Override
        public void onOpen(ServerHandshake handshakedata) {
            send("Hello, it is me. Mario :)");
            System.out.println("new connection opened");
        }

        @Override
        public void onClose(int code, String reason, boolean remote) {
            System.out.println("closed with exit code " + code + " additional info: " + reason);
        }

        @Override
        public void onMessage(String message) {
            System.out.println("received message: " + message);
        }

        @Override
        public void onMessage(ByteBuffer message) {
            System.out.println("received ByteBuffer");
        }

        @Override
        public void onError(Exception ex) {
            System.err.println("an error occurred:" + ex);
        }

    }

    private Button start;
    private TextView output;
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_csm_connection);
        start = (Button) findViewById(R.id.start);
        output = (TextView) findViewById(R.id.output);

        start.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                WebSocketClient client = null;
                try {
                    client = new EmptyClient(new URI("ws://192.168.2.234:54321"));
                } catch (URISyntaxException e) {
                    e.printStackTrace();
                }
                client.connect();
                client.getConnection();

            }
        });
    }

}

我想接收从服务器获取的数据，服务器的IP地址为ws://192.168.2.234:54321。我不确定如何从服务器中打印出数据。

我知道我可以连接到服务器。我尝试使用onMessage()函数，但是我意识到我不会从客户端输入任何内容。

我想从服务器获取消息并显示它。我该怎么做？