菜单片段类未被调用

Question

I wish control my menu through a Fragment in order to minimise code duplication. The problem I have is that the activity class receives the call when debugging, but it does not continue to the Fragment class. Classes shown below.

I thought that the Fragment 'participates' in the layout lifecycle when inheriting from Fragment. What am I missing here?

SomeActivity.java

public class SomeActivity extends Activity {

    /**
     * Called when the activity is first created.
     */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        getActionBar().show();
        setContentView(R.layout.a);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        MenuInflater menuInflater = getMenuInflater();
        menuInflater.inflate(R.menu.main, menu);
        return super.onCreateOptionsMenu(menu);
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        return super.onOptionsItemSelected(item);
    }

    public void chooseLanguage(View view) {
        Intent intent = new Intent(this, AActivity.class);
        startActivity(intent);
    }
}

MenuFragment.java

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

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

    public void startActivity(Class classs) {
        Intent intent = new Intent(getActivity(), classs);
        startActivity(intent);
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem menuItem) {
        switch (menuItem.getItemId()) {
            case R.id.a:
                startActivity(AActivity.class);
                return true;
            case R.id.b:
                startActivity(BActivity.class);
                return true;
            case R.id.c:
                startActivity(CActivity.class);
                return true;
            case R.id.d:
                startActivity(DActivity.class);
                return true;
            default:
                return super.onOptionsItemSelected(menuItem);
        }
    }
}

Answer 1

From documentioned of onCreateOptionsMenu() of Activity :

You must return true for the menu to be displayed; if you return false it will not be shown.

So make sure to return true instead of

return super.onCreateOptionsMenu(menu);

Answer 2

So the solution consists of

Adding the Fragment in the Activity's onCreate

getFragmentManager().beginTransaction().add(new MenuFragment(), "Menu fragment").commit();

Then onOptionsItemSelected in the Activity should return false as according to the documentation

boolean Return false to allow normal menu processing to proceed, true to consume it here.

https://developer.android.com/reference/android/app/Activity.html#onOptionsItemSelected(android.view.MenuItem)