如何使用Fragments在NavigationDrawer上隐藏OptionsMenu？

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 Fragment s).

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() .

Answer 2

In your fragment onCreate, add this :

setHasOptionsMenu (true);

And then hide through onPrepareOptionsMenu. eg

@Override
    public void onPrepareOptionsMenu(Menu menu) {
        super.onPrepareOptionsMenu(menu);
        menu.findItem(R.id.action_settings).setVisible(false);
    }

Answer 3

Check out this answer here: https://stackoverflow.com/a/18135409/2558344 . Its basically using a boolean to clear items in the navigation drawer and vice versa. But alternatively, you could declare Menu menu as a private variable in your class and use it as: onCreateOptionsMenu(menu, MenuInflater inflater) .

Then check in your fragments onStop() , onPause() if it's displaying items or not, if yes then clear them, like:

if (menu != null)
    menu.clear();

Answer 4

If you've implemented the navigation drawer the way Android Studio sets it up for you in its example code with a NavigationDrawerFragment , you should have two xml to start with main.xml (activity wide actionbar menu items) and global.xml (global items). I then added a fragment specific menu which adds items to the "activity menu items" as long as the drawer is closed...

Activity:

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

NavigationDrawerFragment

@Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
    // If the drawer is open, show the global app actions in the action bar. 
    // See also showGlobalContextActionBar, which controls the top-left area 
    // of the action bar.
    if (mDrawerLayout != null && isDrawerOpen()) {
        inflater.inflate(R.menu.global, menu);
        showGlobalContextActionBar();
    }
    super.onCreateOptionsMenu(menu, inflater);
}

and in your fragments add as you've described above

@Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
    // Add fragment specific action bar items to activity action bar items.
    // Activity wide items are in main.xml
    // Visible action bar items if navigation drawer is visible/open 
    // are in global.xml
    super.onCreateOptionsMenu(menu, inflater);
    if (!mNavigationDrawerFragment.isDrawerOpen()) {
        inflater.inflate(R.menu.fragment_menu, menu);
    }
}