How to hide OptionsMenu on NavigationDrawer using Fragments?

Question

I am creating android application and I'm trying to respect as much as possible the latest Android usability standards. In particular, I am preparing the user interface using the navigation drawer, and I'm trying to ensure compatibility with 2.1+ Android versions. To appreciate the problem, the project consists of:

• A main activity;
• A navigation drawer;
• Four fragments (with their associated layouts).

The problem I'm experiencing occurs when opening the navigation drawer: although each Fragment has its specific menu, when I open the navigation drawer it is added to the nav drawer menu. I tried in several ways (invalidateOptionMenu(), menu.clear(), manipulating functions isDrawerOpen() and isDrawerClose() and more), but I cannot remove the Fragment's menu when opening the navigationdrawer.

These are some snippets of my code, much of it generated by Android Studio, the IDE I'm using:

In main activity:

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    if (!mNavigationDrawerFragment.isDrawerOpen()) {
        // Only show items in the action bar relevant to this screen
        // if the drawer is not showing. Otherwise, let the drawer
        // decide what to show in the action bar.
        getMenuInflater().inflate(R.menu.global, menu);
        restoreActionBar();
        return true;
    }
    return super.onCreateOptionsMenu(menu);
}

where "global" is a simple menu with a classical "ic_action_overflow".

And in my fragments I've:

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setHasOptionsMenu(true);
}

@Override
public void onPrepareOptionsMenu(Menu menu) {
    super.onPrepareOptionsMenu(menu);
}

@Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
    super.onCreateOptionsMenu(menu, inflater);
    inflater.inflate(R.menu.fragment1, menu);
}

(It's the same of the other Fragments).

Someone can give me some advice on how to act?

Answer 1

I faced the same problem using the boilerplate code generated by Android Studio and got it working by modifying the menu in NavigationDrawerFragment.onPrepareOptionsMenu() (in my case, I wanted to clear the menu altogether):

@Override
public void onPrepareOptionsMenu(Menu menu) {
    if (mDrawerLayout != null && isDrawerOpen()) {
        menu.clear();
    }
}

This is roughly how the options menu is recreated:

1. NavigationDrawerFragment, which is generated by the IDE, calls supportInvalidateOptionsMenu() when the drawer is opened or closed.
2. onCreateOptionsMenu gets called: The hosting activity and each of the added fragments gets a chance to contribute menu items.
3. onPrepareOptionsMenu gets called: Again, the hosting activity and each of the added fragments get a chance to modify the menu.

The fragments are iterated in the order they were added. There is no way to stop the chain of calls midway in steps 2. and 3.

So the idea is to let NavigationDrawerFragment do last-minute changes to the menu in its onPrepareOptionsMenu and no other fragments.

If you need to let other fragments do something in onPrepareOptionsMenu, then you may have to setup those other fragments so they can determine if the drawer is open or not and change their behavior accordingly. This may mean perhaps adding a isDrawerOpen method to the hosting activity or passing in the drawer identifiers to the fragment like it's done in NavigationDrawerFragment.setup().