将XML中的菜单项投射到微调框（Actionbar appcompat）

Question

I'm having some trouble casting a Menu Item in xml to a Spinner (actionbar compat) . I've tried a couple of options, like these Spinner as MenuItem not initialized by findViewById or Adding spinner to ActionBar (not Navigation , but spinner = (Spinner)item.getActionView(); keeps coming back as null. Setting up a new spinner works though, but that's probably not relevant to my problem.

Code:

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {

        MenuInflater inflater = getMenuInflater();
        inflater.inflate(R.menu.main, menu);

        actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_LIST);

        //spinner = (Spinner) menu.findItem(R.id.category_spinner).getActionView();
        //spinner = new Spinner(this);

        MenuItem item = menu.findItem(R.id.category_spinner);
        spinner = (Spinner)item.getActionView();

        SpinnerAdapter mSpinnerAdapter = ArrayAdapter.createFromResource(this, R.array.operating_systems,android.R.layout.simple_spinner_dropdown_item);
        spinner.setAdapter(mSpinnerAdapter);
        actionBar.setListNavigationCallbacks(mSpinnerAdapter, mOnNavigationListener);
        mOnNavigationListener = new ActionBar.OnNavigationListener() {

            String[] strings = getResources().getStringArray(R.array.operating_systems);

            @Override
            public boolean onNavigationItemSelected(int position, long itemId) {
                ListContentFragment newFragment = new ListContentFragment();
                FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
                ft.replace(R.id.fragment_container, newFragment, strings[position]);
                ft.commit();
                return true;
            }
        };

        return super.onCreateOptionsMenu(menu);
    }

I also tried

    MenuItem item = menu.findItem(R.id.category_spinner_item);
    spinner = (Spinner) MenuItemCompat.getActionView(item);

http://developer.android.com/guide/topics/ui/actionbar.html#ActionView but also comes back null.

menu/main.xml

<menu xmlns:android="http://schemas.android.com/apk/res/android"
      xmlns:yourapp="http://schemas.android.com/apk/res-auto" >


    <item
            android:id="@+id/category_spinner"
            android:showAsAction="ifRoom"
            android:actionLayout="@layout/action_sort"  />

    <item android:id="@+id/action_share"
          android:icon="@drawable/ic_action_share"
          android:title="@string/action_share"
          yourapp:showAsAction="ifRoom"  />

    <item android:id="@+id/action_settings"
          android:icon="@drawable/ic_action_overflow"
          android:title="@string/action_settings"
          yourapp:showAsAction="always"/>


</menu>

layout/action_short.xml

<Spinner xmlns:android="http://schemas.android.com/apk/res/android"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:entries="@array/operating_systems" />

Answer 1

getActionView() of my MenuItem return null answers it all:

getActionView() only works if there's a custom actionView from setActionView.

Why though, I have No idea. Why they dont in the example here http://developer.android.com/guide/topics/ui/actionbar.html#ActionView , who knows.