ServerSocket in android not accepting while on SLEEP MODE [screen off]

Question

I need to accept data using a ServerSocket which is in thread that is in a Background service ServerSocket accepts data fine when the device [Galaxy s3 19300, Android 4.1.2] is in WAKE state. But ServerSocket doesn't seems to accept when the device is in SLEEP mode, ie when the screen is turned off.

I tried using WIFI locks, full and partial and also POWER locks, but both options couldn’t make the ServerSocket listen.

Any clues to solve this folks?

The code

// -------------------------------------------------------------------------
private void CallSock() {
    Log.i("$$$$$",
        "Before WiFI State is " + Integer.toString(wm.getWifiState()));
    wm = (WifiManager) mContext.getSystemService(Context.WIFI_SERVICE);
    wifiLock = wm.createWifiLock(WifiManager.WIFI_MODE_FULL, "MyWifiLock");
    PowerManager mgr = (PowerManager) mContext
            .getSystemService(Context.POWER_SERVICE);
    WakeLock wakeLock = mgr.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK,
        "MyWakeLock");
    wakeLock.acquire();
    if (!wifiLock.isHeld()) {
        wifiLock.acquire();
        Log.i("$$$$$", "Wifi lock acquired");
    }
    Looper.prepare();
    sSocket = new ServerSocket(serverPort);
    while (true) {
        Log.i("$$$$$", "In the While loop WiFI State is "
                + Integer.toString(wm.getWifiState()));
        Rulecontent.writeLogInfo("Waiting to recieve file");
        String fileName = readFile();
    }
}

// -------------------------------------------------------------
public String readFile() {
    StringBuilder x = null;
    try {
        InputStream in = null;
        Socket recvClientSocket = sSocket.accept();
        in = recvClientSocket.getInputStream();
        byte[] bytes = new byte[1024];
        x = new StringBuilder();
        int numRead = 0;
        while ((numRead = in.read(bytes)) >= 0) {
            x.append(new String(bytes, 0, numRead));
        }
    } catch (IOException e) {
        e.printStackTrace();
    }
    return x.toString();
}
// -------------------------------------------------------------------------

Answer 1

Ensure that you have the android.permission.WAKE_LOCK permission and the user has set their Wifi settings to "Never Sleep" in the Android Wifi Manager.

I have verified that ServerSocket works with the screen off in Android 4.0 in a standard Thread (launched by an Activity) -- I have not tried it as a Background Service. I am able to send commands to my phone every 10 minutes from an external server.

Code snippet for acquiring the Wifi and Power locks, which are both required:

https://stackoverflow.com/a/18916511/830775