ActionBar up navigation recreates parent activity instead of onResume

Add the following to your parent activity in the manifest file

android:launchMode="singleTop"

regarding to this answer

The reason, the activities are recreated when using up-navigation is, that android uses standard launch mode for this, if you do not specify an other mode. That means

"The system always creates a new instance of the activity in the target task"

and thus the activity is recreated (see docu here).

A solution would be to either declare the launch mode of the MainActivity as

android:launchMode="singleTop"

in the AndroidManifest.xml
_{(should always work together with Intent.FLAG_ACTIVITY_CLEAR_TOP)}

or you could add FLAG_ACTIVITY_SINGLE_TOP to your intent flags, to tell the activity, that it should not be recreated, if it is on the back stack, e.g.

Intent h = NavUtils.getParentActivityIntent(this); 
h.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_SINGLE_TOP); 
NavUtils.navigateUpTo(this, h);

This code worked for me:

Intent upIntent = NavUtils.getParentActivityIntent(this);
if (NavUtils.shouldUpRecreateTask(this, upIntent)) {
    // This activity is NOT part of this app's task, so create a new task
    // when navigating up, with a synthesized back stack.
    TaskStackBuilder.create(this)
        // Add all of this activity's parents to the back stack
        .addNextIntentWithParentStack(upIntent)
        // Navigate up to the closest parent
        .startActivities();
} else {
    // This activity is part of this app's task, so simply
    // navigate up to the logical parent activity.
    upIntent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
    NavUtils.navigateUpTo(this, upIntent);
}

return true;

No finish() invocation required.