无法在Android emulator客户端中从python服务器接收数据

我试图编写一个基于python（套接字）的服务器和一个Android客户端，但是 将数据从服务器发送到客户端时，客户端不会收到任何数据。服务器从客户端接收数据。
我认为问题可能出在emulator上，而不是服务器上，因为我确实建立了连接，来自服务器的消息可能被emulator的防火墙阻止。 代码如下：

客户：

public class MainActivity extends AppCompatActivity {
    Thread Thread1 = null;
    EditText etIP, etPort;
    TextView tvMessages;
    EditText etMessage;
    Button btnSend;
    String SERVER_IP;
    int SERVER_PORT;
    Boolean done = false;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        etIP = findViewById(R.id.etIP);
        etPort = findViewById(R.id.etPort);
        tvMessages = findViewById(R.id.tvMessages);
        etMessage = findViewById(R.id.etMessage);
        btnSend = findViewById(R.id.btnSend);
        Button btnConnect = findViewById(R.id.btnConnect);

        btnConnect.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                done = false;
                tvMessages.setText("");
                SERVER_IP = etIP.getText().toString().trim();
                SERVER_PORT = Integer.parseInt(etPort.getText().toString().trim());
                Thread1 = new Thread(new Thread1());
                Thread1.start();
            }
        });
        btnSend.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String message = etMessage.getText().toString().trim();
                if (!message.isEmpty()) {
                    if(! done) {
                        String android_id= Settings.Secure.getString(MainActivity.this.getContentResolver(),
                                Settings.Secure.ANDROID_ID);
                        new Thread(new Thread3(android_id)).start();
                        done = true;
                    }
                    new Thread(new Thread3(message)).start();
                }
            }
        });
    }
    private PrintWriter output;
    private BufferedReader input;
    class Thread1 implements Runnable {
        public void run() {
            Socket socket;
            try {
                socket = new Socket(SERVER_IP, SERVER_PORT);
                output = new PrintWriter(socket.getOutputStream());
                input = new BufferedReader(new InputStreamReader(socket.getInputStream()));
                runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                        tvMessages.setText("Connected\n");
                    }
                });
                new Thread(new Thread2()).start();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
    class Thread2 implements Runnable {
        @Override
        public void run() {
            while (true) {
                try {
                    final String message = input.readLine();
                    if (message != null) {
                        runOnUiThread(new Runnable() {
                            @Override
                            public void run() {
                                tvMessages.append("server: " + message + "\n");
                            }
                        });
                    } else {
                        Thread1 = new Thread(new Thread1());
                        Thread1.start();
                        return;
                    }
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }
    class Thread3 implements Runnable {
        private String message;
        Thread3(String message) {
            this.message = message;
        }
        @Override
        public void run() {
            output.write(message);
            output.flush();
            runOnUiThread(new Runnable() {
                @Override
                public void run() {
                    tvMessages.append("client: " + message + "\n");
                    etMessage.setText("");
                }
            });
        }
    }
}

服务器：

with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
    s.bind((HOST, PORT))
    s.listen()
    conn, addr = s.accept()
    with conn:
        print('Connected by', addr)
        while True:
            data = conn.recv(1024)
            if not data:
                break
            conn.sendall(data)

---

感谢这种单向行为，

client->server

起作用，而

server->client

不起作用，这是由于模拟器是NAT的，很可能您必须设置一个规则来将入站流量（从本地主机端口）转发到模拟器的本地端口

更多信息和例子