要实现Android从Python服务器接收消息，你可以使用Socket编程来建立一个TCP连接。以下是一个基本的示例代码：

在Android端：

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.Socket;

public class MainActivity extends AppCompatActivity {

    private static final String SERVER_IP = "your_server_ip";
    private static final int SERVER_PORT = 12345;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    Socket socket = new Socket(SERVER_IP, SERVER_PORT);

                    BufferedReader reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
                    String message = reader.readLine();

                    // 在这里处理接收到的消息
                    Log.d("Received Message", message);

                    socket.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }).start();
    }
}

在Python服务器端：

import socket

SERVER_IP = 'your_server_ip'
SERVER_PORT = 12345

def main():
    server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    server_socket.bind((SERVER_IP, SERVER_PORT))
    server_socket.listen(1)
    print('Server listening on {}:{}'.format(SERVER_IP, SERVER_PORT))

    while True:
        client_socket, client_address = server_socket.accept()
        print('Connection from:', client_address)

        message = 'Hello from Python server!'
        client_socket.sendall(message.encode())

        client_socket.close()

if __name__ == '__main__':
    main()

请确保将your_server_ip替换为你的服务器IP地址，并确保Android设备和Python服务器在同一个网络下。