Can't establish socket connection between Java and Android

Question

I am currently trying to host a server socket on my android phone, and use my computer to connect to that one. There are several applications which already do so (for example Skype), so it has to be possible. The problem I am currently facing, is that I cannot connect to the server socket opened on my emulator. This is code I am running in Android Developer Tools emulator to open my server socket:

public void run(){
    Log.i(TAG, "1");
    try{
      serverSocket = new ServerSocket(25555);
      Log.i(TAG, "2. Details: " + serverSocket);
      while(true)
      {
      clientSocket = serverSocket.accept(); //it keeps sticking here, and waiting for connections.
      Log.i(TAG, "3");

      in = new BufferedReader(
             new InputStreamReader(clientSocket.getInputStream()));
      out = new PrintWriter(clientSocket.getOutputStream(), true);

      String input = in.readLine();
      out.println("received: " + input);

      in.close();
      out.close();
      }
    } catch(Exception e) {
        Log.i(TAG, "ERROR:");
    e.printStackTrace();
    }
  }

and this is the code I am running in normal eclipse to connect to this server socket:

try {
    socket = new Socket(-snip-,25555);
    System.out.println("Connection has been made");
  } catch (NumberFormatException e) {
    System.out.println("Connection wasn't made. Closing the application.");
  }

This just gives me this error:

Exception in thread "main" java.net.ConnectException: Connection refused: connect
    at java.net.DualStackPlainSocketImpl.connect0(Native Method)
    at java.net.DualStackPlainSocketImpl.socketConnect(Unknown Source)
    at java.net.AbstractPlainSocketImpl.doConnect(Unknown Source)
    at java.net.AbstractPlainSocketImpl.connectToAddress(Unknown Source)
    at java.net.AbstractPlainSocketImpl.connect(Unknown Source)
    at java.net.PlainSocketImpl.connect(Unknown Source)
    at java.net.SocksSocketImpl.connect(Unknown Source)
    at java.net.Socket.connect(Unknown Source)
    at java.net.Socket.connect(Unknown Source)
    at java.net.Socket.<init>(Unknown Source)
    at java.net.Socket.<init>(Unknown Source)

Now my question is, is it something I did wrong in my code, or is it some problem with the emulator?

By the way, I added those lines of code to my AndroidManifest.xml:

    <uses-permission android:name="android.permission.INTERNET" >
    </uses-permission>

Thanks in advance.

I cut my own IP out. Don't like to have it just standing online :P. — user3254705, Feb 05 '14 at 16:35
What I understand is that you have a Server Socket on an Android Device (Emulator), so you're trying to connect from your computer to Emulator, is it true?. If that's the case it means you have the wrong IP (`-snip-`). — Julián Chamalé, Feb 05 '14 at 16:43
Sorry, I must have been confusing two things. I am running the server socket on an android virtual device. Thought that meant the same as an emulator. — user3254705, Feb 05 '14 at 16:47
I still a little bit confused, but I think that your `-snip-` IP should be the IP of your Android Virtual Device (the server IP, not the client). — Julián Chamalé, Feb 05 '14 at 16:50

score 0 · Accepted Answer · edited May 23 '17 at 11:33

0

Acording to the discussion, you have to connect a client to an Android Virtual Device Server. This means you need to know you Android Virtual Device's IP. There are some ways to achieve this:

The first is to create a network and then connect both your Android Device and your Computer/Client, and then they will have an IP.
You can assign an static IP to the Android Device, in this case you should check this link.

edited May 23 '17 at 11:33

Community

1
1

answered Feb 05 '14 at 17:04

Julián Chamalé

607
11
23

Well, I tried to connect to 10.0.0.2:25555, but if I do, it waits for a few seconds and then gives me this error:`Exception in thread "main" java.net.ConnectException: Connection timed out: connect` – user3254705 Feb 05 '14 at 18:45
Did you tried to ping server and client ? `ping 10.0.0.2` – Julián Chamalé Feb 05 '14 at 19:22
By the way, I meant 10.0.2.2 instead of 10.0.0.2. – user3254705 Feb 05 '14 at 20:01
Again, you're trying to ping the computer, not the emulator. Did you try `adb shell` and then `ifconfig eth0`, it should display your emulator IP. – Julián Chamalé Feb 05 '14 at 20:53

Can't establish socket connection between Java and Android

1 Answers1