Android Java TCP/IP server to service

Question

I can not add TCP/IP Server to the service, when closing (minimizing) the application, the server does not accept data. How to make the data transmitted continuously?

public int onStartCommand(Intent intent, int flags, int startId) {
    myServer = new Server();
    myServer.start();  
    return Service.START_STICKY;
}

Server

 private class Server extends Thread {
    private Socket clientSocket; 
    private  ServerSocket server; 
    private  BufferedReader in; 
    private  BufferedWriter out; 
    private String LOG_TAG;

    @Override
    public void run() {
      while (true) {
            try {
                server = new ServerSocket(9002);
                clientSocket = server.accept();
                try {
                    try {
                        in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
                        out = new BufferedWriter(new OutputStreamWriter(clientSocket.getOutputStream()));
                        String word = in.readLine();
                        Log.d(LOG_TAG, "***" + word + "***");
                        out.write(word);
                        out.flush();
                    } finally {
                        System.out.println("run closed");
                        clientSocket.close();
                        in.close();
                        out.close();
                    }
                } finally {
                    System.out.println("Server closed");
                    server.close();
                }
            } catch (IOException e) {
                System.err.println(e);
            }
        }
    }
}

Answer 1

So many problems with this code. Here's a list of them:

• You'd need to be a foreground service, or Android will eventually kill your service.
• You're making a server socket and accepting a single connection to it, then making another in a loop. That's not how you do it. You make the server socket once, and accept() for each incoming connection
• As a consequence of the above, the second time will always fail, because the port won't be immediately available unless you use a socket with SO_REUSEADDR set. see the setReuseAddress call on ServerSocket
• You're catching all exceptions blindly. I would highly suspect you're throwing an exception and ignoring it, causing it all to not work
• This code won't work on any cellular network, as a NAT will be put between you and the world.
• Even on wifi you need to make sure your network allows incoming connections to your device. The default on most home routers is not to.