Update selected state of navigation drawer after back press

Question

Whats the proper way to handle the selected state of the navigation drawer after back press?

I have a navigation drawer with n entries (in a listview) like the SDK sampl

Answer 1

Building upon @matiash 's excellent answer (be sure to +1 his/hers if you +1 my answer)

To start, we're assuming we're in the Activity

getFragmentManager().addOnBackStackChangedListener(
    new FragmentManager.OnBackStackChangedListener() {
        public void onBackStackChanged() {
            // Update your UI here.
        }
    });

You can find the current fragment with the following:

(from https://stackoverflow.com/a/24589081/878159)

Fragment f = getFragmentManager().findFragmentById(R.id.frag_container);
if (f instanceof CustomFragmentClass) {
    // do something with f
    f.doSomething();
}

That should get you a step closer. Then something like this will get you a reference to your nav drawer:

nav = (NavigationDrawerFragment) getFragmentManager().findFragmentById(R.id.nav);

Then depending how you setup your drawer fragment code:

nav.updateSelected(position);

The updateSelected(int) method would be in your NavigationDrawerFragment class and might look something like this:

public void updateSelected(int position) {
    mCurrentSelectedPosition = position;
    if (mDrawerListView != null) {
        mDrawerListView.setItemChecked(position, true);
    }
}

NOTE: there are many ways to do this, but this should get you started.