onDestroy() won't get called after this.finish()

Question

Hi everyone,

I'm wondering why the Motorola Milestone with 2.1-update1 behaves differently from the Emulator or e.g. the Nexus One. I am trying to exit my app with:

@Override
protected void onPause() {
    if(mayDestroyActivity) this.finish();
    super.onPause();
}

This works well on either Emulator or Nexus One. onDestroy() gets called immediatly after onPause() and onStop. But not for the Milestone. Instead, onDestroy() gets called when another Activity is started. Its section in the Manifest looks like this:

<activity android:name=".MyActivity"  
    android:configChanges="orientation|keyboardHidden"  
 android:label="@string/questionnaire_item"
 android:launchMode="singleInstance"
    android:theme="@android:style/Theme.NoTitleBar.Fullscreen"
 android:windowSoftInputMode="adjustPan">
 <intent-filter>
  <category android:name="android.intent.category.OPENABLE" />
 </intent-filter>
</activity>

Does anyone have a hint on this? My app depends on exiting properly since I save all progress in onDestroy()

Thanks,
Steff

Answer 1

You are doing it wrong. This is what the Doc says:

Note: do not count on this method being called as a place for saving data! [...] 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.

http://developer.android.com/reference/android/app/Activity.html#onDestroy%28%29

Answer 2

You should use onSaveInstanceState, check this link.

Answer 3

If the user exits to the home screen this does not need to mean that the app should be exited. In most of the time it will give a better user experience if the app just goes to the background. Try to rely on saveInstanceState and onPause.

Exiting a app is seen as bad practice in the android world, featuring a phone with a good system for true multitouch can get better user experience if the app keeps running after pressing the home screen.