我如何使菜单选项菜单出现在ViewPager Fragments中？

Question

我有一个其中包含ViewPager的FragmentActivity，并且需要屏幕顶部操作栏中的选项菜单。我添加到ViewPager中的片段中对public void onCreateOptionsMenu(Menu menu, MenuInflater inflater)的调用从未被调用，因此从不创建选项菜单，并且不显示任何操作栏。

我已将setHasOptionsMenu(true);添加到片段的public void onCreate(@Nullable Bundle savedInstanceState)中。 我还尝试过将选项菜单直接添加到包含ViewPager的FragmentActivity中，但这似乎也不起作用。

MainActivity

public class MainActivity extends FragmentActivity {

    private PagerAdaptor pager;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        setContentView(R.layout.activity_main);
        setupPageViewer();
        super.onCreate(savedInstanceState);
    }

    private void setupPageViewer() {
        UIControlSurface cs = new UIControlSurface();
        UIControlSurface cs2 = new UIControlSurface();
        pager = new PagerAdaptor(getSupportFragmentManager());
        pager.addPage(cs);
        pager.addPage(cs2);
        ViewPager v_pager = (ViewPager)super.findViewById(R.id.view_pager);
        v_pager.setAdapter(pager);
        v_pager.postInvalidate();
    }
}

activity_main.xml

<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/button_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:visibility="visible"
    tools:context=".MainActivity">

    <android.support.v4.view.ViewPager
        android:id="@+id/view_pager"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:visibility="visible" />
</android.support.constraint.ConstraintLayout>

UIControlSurface.java

public class UIControlSurface extends Fragment implements UIEditableListener{


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

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

    @Override
    public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
        Log.i("Menu Inflation", "Here i am!");// never logged
        inflater.inflate(R.menu.navi, menu);
    }

    @RequiresApi(api = Build.VERSION_CODES.JELLY_BEAN_MR1)
    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) {
            case R.id.navi_enter_edit:
                return true;
            case R.id.navi_cancel:
                return true;
        }
        return false;
    }
}

ui_control_surface.xml

<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/button_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <Button
        android:id="@+id/add_button"
        style="@style/Widget.AppCompat.Button.Colored"
        android:layout_width="52dp"
        android:layout_height="54dp"
        android:layout_marginTop="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginRight="8dp"
        android:text="+"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
</android.support.constraint.ConstraintLayout>

在片段的onCreate方法中调用setHasOptionsMenu(true);时，我希望菜单已创建，但是操作栏和选项菜单从不出现。片段按预期出现在ViewPager中，只是没有可见的选项菜单。