我試圖在Android中通過TCP套接字發送消息，但它不起作用。（我的手機是客戶端）下面是來自類 TCPClient 的代碼：public class TcpClient {    public static String SERVER_IP = "192.168.200.1"; //server IP address    public static final int SERVER_PORT = 1500;    // message to send to the server    private String mServerMessage;    // sends message received notifications    private OnMessageReceived mMessageListener = null;    // while this is true, the server will continue running    private boolean mRun = false;    // used to send messages    private PrintWriter mBufferOut;    // used to read messages from the server    private BufferedReader mBufferIn;    private Socket socket;    private Context context;    /**     * Constructor of the class. OnMessagedReceived listens for the messages received from server     */    public TcpClient(OnMessageReceived listener) {        mMessageListener = listener;    }    /**     * Sends the message entered by client to the server     *     * param message text entered by client     */    public String sendMessage(String message) {        byte[] bytesToSend = message.getBytes();        if (bytesToSend != null && socket != null && socket.isConnected()) {            try {                socket.getOutputStream().write(bytesToSend, 0, 9);                return "deu";            } catch (Exception e2) {                e2.printStackTrace();                return e2.getMessage();            }        }        else return "aa";    }    /**     * Close the connection and release the members     */    public void stopClient() {        sendMessage("disconnecting");        mRun = false;        if (mBufferOut != null) {            mBufferOut.flush();            mBufferOut.close();        }        mMessageListener = null;        mBufferIn = null;        mBufferOut = null;        mServerMessage = null;    }