TCP socket on Android 4.0.3

Question

I am working on a project in which I have a TCP connection with a server via Android.
I am using the following code:

public class MyService extends Service {
private static final String TAG = "MyService";
MediaPlayer player;
Socket s;
@Override
public IBinder onBind(Intent intent) {
    return null;
}

@Override
public void onCreate() {
    Toast.makeText(this, "My Service Created", Toast.LENGTH_LONG).show();
    Log.d(TAG, "onCreate");

    player = MediaPlayer.create(this, R.raw.braincandy);
    player.setLooping(false); // Set looping
}

@Override
public void onDestroy() {
    Toast.makeText(this, "My Service Stopped", Toast.LENGTH_LONG).show();
    Log.d(TAG, "onDestroy");
    player.stop();
    try {
        s.close();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
}

@Override
public void onStart(Intent intent, int startid) {
    Toast.makeText(this, "My Service Started", Toast.LENGTH_LONG).show();
    Log.d(TAG, "onStart");
    player.start();
    try {
        s = new Socket("192.168.1.54", 64000);
    } catch (UnknownHostException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
}
 }

I am running the connection as a service.

The real problem is I can make a connection with my Android phone (2.3.7) and with the emulator (2.3.3) but when I want to test in on my tablet (4.0.3), my app always crashes when I want to start the connection.

Can someone help me with this?

Here is the logcat log: FATAL EXCEPTION: main java.lang.RuntimeException: Unable to start service

com.gunther.servicetcp.MyService@412b0a98 with Intent 
{    cmp=com.gunther.servicetcp/.MyService }: android.os.NetworkOnMainThreadException
at android.app.ActivityThread.handleServiceArgs(ActivityThread.java:2376)
at android.app.ActivityThread.access$1900(ActivityThread.java:123)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1210)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4424)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
at dalvik.system.NativeStart.main(Native Method)
Caused by: android.os.NetworkOnMainThreadException
0at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1099)
at libcore.io.BlockGuardOs.connect(BlockGuardOs.java:84)
at libcore.io.IoBridge.connectErrno(IoBridge.java:127)
at libcore.io.IoBridge.connect(IoBridge.java:112)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:192)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:172)
at java.net.Socket.startupSocket(Socket.java:566)
at java.net.Socket.tryAllAddresses(Socket.java:127)
at java.net.Socket.<init>(Socket.java:177)
at java.net.Socket.<init>(Socket.java:149)
at com.gunther.servicetcp.MyService.onStart(MyService.java:53)
at android.app.Service.onStartCommand(Service.java:438)
at android.app.ActivityThread.handleServiceArgs(ActivityThread.java:2359)
:   ... 10 more

Have you also tried a 4.0.3 emulator? And it'll be useful to post the log error from LogCat, when your app crashes. — Adinia, Apr 25 '12 at 10:08
Ok, then edit your question and post the stack trace of the crash...you should always do so if you need help with a crash. — Adinia, Apr 25 '12 at 10:38
In DDMS perspective, go up in menu to Window - Show View - Logcat; then on left, clic the device/ emulator name, and run your app; on right you'll see some info in red, related to the crash of your app. — Adinia, Apr 25 '12 at 10:59

score 4 · Accepted Answer · answered Apr 25 '12 at 11:59

4

You shouldn't do network operations on the main thread. This will lead to your app being unresponsive. Before Honeycomb you could get away with it, but Honeycomb and newer Android versions will check and throw the exception you're getting. See also this page of the Android Developers API

answered Apr 25 '12 at 11:59

THelper

15,333
6
64
104

Hmm, good to know now but I aint doing any network operations in the main activity? I am just starting a service from the main acitivity, in this service which I posted I start the socket, but maybe the problem is that i'm calling it from the main activity? How should i fix this then, run a new acitivty or a new class or something? – Gvg Apr 25 '12 at 12:36
@GuntherVanGeetsom From your stacktrace I gather that are creating a socket (line 53 of your `com.gunther.servicetcp.MyService` class). Try creating that in a separate thread. You can use an AsyncTask like in [this post](http://stackoverflow.com/q/6343166/741249) for example. – THelper Apr 25 '12 at 12:55

score 2 · Answer 2 · edited Sep 25 '12 at 21:38

2

Services's onStart() method runs on the main thread, (yes, services seem to run on the main thread of the application.) so you should fork another thread in the onStart() method and do everything you need to do in that thread.

edited Sep 25 '12 at 21:38

biegleux

13,179
11
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52

answered Sep 07 '12 at 09:42

Lake

21
1

TCP socket on Android 4.0.3

2 Answers2