Question

I have a method like this in my class which extends Activity

@Override
public void onDestroy() {
    Log.i("onDestory: ", "Inside OnDestory!");
    bluetoothCommunicator.destroyedApp();
    super.onDestroy(); 
}

The method destroyedApp() look like this:

public void destroyedApp() {
        if(server != null)
            server.destroy();   
}

Where server is an Instance of a class which extends Thread

Here is the scenario:

I’m opening the application for the first time, inside my onCreate method, I create a new instance of the bluetooth class which sets up the BluetoothServerSocket, this works fine and I’m able to transfer files to my phone.

This also works when I have my application in the background, because the thread is still alive.

But

When I’m killing the application, according to the Activity Life Cycle

The onDestroy() method should be called by the Android Framework. And when I’m launching the application once more, the onCreate method should be called, but it doesnt seems that an instance of the BluetoothServerSocket is being created. I have no LogCat info, because the device which sends the bluetooth file, only says:

Error Log:
Write Error: 
Transport endpoint is not connected
__obex_connect:
error=-2
Unable to connect to the server
Error

Which tells me that the BluetoothServerSocket is not "alive"

Any suggestion on how I can accomplish this?

Answer 1

There is generally no guarantee that the onDestroy() method will be called at all. According to the docs:

Note: do not count on this method being called as a place for saving data! For example, if an activity is editing data in a content provider, those edits should be committed in either onPause() or onSaveInstanceState(Bundle), not here. This method is usually implemented to free resources like threads that are associated with an activity, so that a destroyed activity does not leave such things around while the rest of its application is still running. There are situations where the system will simply kill the activity’s hosting process without calling this method (or any others) in it, so it should not be used to do things that are intended to remain around after the process goes away.

Derived classes must call through to the super class’s implementation of this method. If they do not, an exception will be thrown.

So I would first test if it is being called reliably.

Also, you are callling super.onStop() in your onDestroy(). It should be super.onDestroy()