Android: onCreate() getting called multiple times (and not by me)

android multithreading oncreate
James picture James · Nov 29, 2010 · Viewed 23.3k times · Source

There is something I don't quite understand right now.

My main activity class creates a Service, which creates a new thread that waits for a TCP connection. Once one comes in, it will start a new activity:

Intent dialogIntent = new Intent(getBaseContext(), VoIPCall.class);
dialogIntent.putExtra("inetAddress", clientSocket.getInetAddress());
dialogIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
getApplication().startActivity(dialogIntent);

After that, the onCreate() method of that class gets run. It will create 2 threads: one records and send data, the other one receive and plays data. Those threads have a forever while loop.

For some reason, I notice that the onCreate() of that last class gets called again, which makes my program crash. I do not understand why it is called again as only the 2 threads are running, there is no user interaction. The documentation says: "Called when the activity is first created.". The activity is already running and I am not trying to create it.

Could someone please explain me this behavior?

Answer

xtempore picture xtempore · Nov 29, 2010

Android will recreate your activity after certain "device configuration changes". One such example is orientation. You can read more here... http://developer.android.com/guide/topics/resources/runtime-changes.html

Perhaps something in your threads is doing something which is considered a configuration change?

If that's the case you might find it useful to extend the Application class instead and do your initialization there. See this post... Activity restart on rotation Android

HTH

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