如何在下属片段中使用ActionBar项

Question

I have an Activity that has a tabhost and a ViewPager that support 3 fragments. I want to use the ActionBar (which resides in the Activity) to use and modify menu items selectable from the ActionBar directly in each of the fragments.

What is the best way to send a message from the activity to the fragment to tell it to implement one of the actionbar items?

I have tried the following:

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();

    if (id == R.id.action_settings) {
        FragmentManager manager = getSupportFragmentManager();
        List<Fragment> fs = new ArrayList<>(manager.getFragments());
        int fragId = fs.get(0).getId();
        PlayFragment fragment = (PlayFragment) manager.findFragmentById(fragId);
        fragment.settingsMenu();
        return true;

This is not working, but also is bad form to need to know the order of the fragments to get it to work. This way didn't work for me. I know I could use a broadcastSender to make it work, but that is also bad form. The REAL problem here is that since the fragments are sitting on top of a ViewPager within a TabHost, there is no way to get the id or tag reliably, so

manager.findFragmentById(fragId) and manager.findFragmentByTag("MyFragmentName") are not useful.

When I try to attach the toolBar to an OnClickListener within the fragment, it doesn't work, and fragment has no support for @Override public boolean onOptionsItemSelected(MenuItem item);

I'll keep looking for a solution. Thanks.

Answer 1

I found the answer on another post. The trick is to get the toolbar from the activity but not to use it as an actionbar directly. You need to inflate your own menu, and have access to modifying title etc ;

@Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { return inflater.inflate(R.layout.play_fragment, container, false); }

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    app = JamSessionApplication.getInstance();

    toolbar = (Toolbar) getActivity().findViewById(R.id.toolbar);
    toolbar.setTitle(song);
    // Set an OnMenuItemClickListener to handle menu item clicks
    toolbar.setOnMenuItemClickListener(new Toolbar.OnMenuItemClickListener() {
        @Override
        public boolean onMenuItemClick(MenuItem item) {
            // Handle action bar item clicks here. The action bar will
            // automatically handle clicks on the Home/Up button, so long
            // as you specify a parent activity in AndroidManifest.xml.
            int id = item.getItemId();
            if (id == R.id.action_reverb) {
                Toast.makeText(getActivity(), "Reverb", Toast.LENGTH_SHORT).show();
                return true;
            }
            return true;
        }
    });
   toolbar.inflateMenu(R.menu.menu_play);

}

I still encountered problems with ViewPager/Tabhost toobars working properly. I found an article which was much more helpful in fixing this. https://www.numetriclabz.com/android-tabs-with-fragments-and-viewpager-tutorial/