为什么我的PrintWriter没有将数据发送到服务器？

我正在开发一个Android应用程序。Android应用程序（客户端）将与pc（服务器）连接并共享数据。现在，我可以成功建立连接，但是无法发送数据。这是我的Java文件，具有建立连接和发送数据的所有逻辑。

ServerConnection.java

public class ServerConnection  {

    private static  int SERVER_PORT = 1100;
    private static  String SERVER_IP = "192.168.43.7";
    private boolean isConnected=false,connectionDone=false;
    private boolean mouseMoved=false;
    Context context;
    private Socket socket;
    private PrintWriter out;

    public void startConnection(String port , String ip){
        SERVER_IP = ip.toString();

        ConnectPhoneTask connectPhoneTask = new ConnectPhoneTask();
        connectPhoneTask.execute(SERVER_IP);
    }


    public void sendDataToServer(String text){
        try {
            if(isConnected) {
                out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(socket.getOutputStream())), true); //create output stream to send data to server

            }
        }catch (IOException e){
            Log.e("remotedroid", "Error while creating OutWriter", e);
            Toast.makeText(context, "Error: while creating OutWriter "+e, Toast.LENGTH_LONG).show();
        }
        if(out!=null){
            out.println(text);
        }
        else{
            Log.e("check" , "Something is wrong here");
        }
    }

    public class ConnectPhoneTask extends AsyncTask<String,Void,Boolean> {

        @Override
        protected Boolean doInBackground(String... params) {
            boolean result = true;

            try {
                InetAddress serverAddr = InetAddress.getByName(params[0]);
                socket = new Socket(serverAddr, SERVER_PORT);//Open socket on server IP and port

            } catch (IOException e) {
                Log.e("remotedroid", "Error while connecting", e);
                result = false;
            }
            return result;
        }

        @Override
        protected void onPostExecute(Boolean result)
        {
            isConnected = result;
            try {
                if(isConnected) {
                    out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(socket.getOutputStream())), true); //create output stream to send data to server

                }
            }catch (IOException e){
                Log.e("remotedroid", "Error while creating OutWriter", e);
            }
        }
    }

}

并且此片段将启动连接并发送数据（通过调用sendDataToServer(String text)方法）。

LogIntoServer.java

public class LogIntoServer extends Fragment {

    private EditText ipadr,portadr;
    private Button connect,disconnect;
    ServerConnection serverConnection;
    String SERVER_IP ;
    String SERVER_PORT;
    PrintWriter out;


    public LogIntoServer() {
        // Required empty public constructor
    }


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        View v = inflater.inflate(R.layout.fragment_log_into_server, container, false);
        ipadr      = v.findViewById(R.id.ipadr);
        portadr    = v.findViewById(R.id.portadr);
        connect    = v.findViewById(R.id.connect);
        disconnect = v.findViewById(R.id.disconnect);

        serverConnection = new ServerConnection();
        connect.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                 SERVER_IP = ipadr.getText().toString();
                 SERVER_PORT = portadr.getText().toString();
                 serverConnection.startConnection(SERVER_PORT , SERVER_IP);
                 serverConnection.sendDataToServer("Connection Successful");
            }
        });

        disconnect.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                serverConnection.sendDataToServer("exit");
            }
        });

        return v;
    }

}

如果我双击连接按钮，则它将仅发送一次“连接成功”。请帮忙。