How can I add my spinner to the ActionBar?

问题

I'm trying to get my spinner working as the Action Bar Drop Down List item, but I cant seem to implement it at all, there aren't many tutorials for this after searching through Google. I think its something to do with the .setListNavigationCallbacks(); line of code, I just have no idea how to get this working from that line onwards.

// setup action bar for spinner
    ActionBar bar = getActionBar();
    bar.setNavigationMode(ActionBar.NAVIGATION_MODE_LIST);
    bar.setListNavigationCallbacks();

    Spinner spinner = (Spinner) findViewById(R.id.spinner1);
    ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(this, R.array.tools_array_stopwatch, android.R.layout.simple_spinner_item);
    adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    spinner.setAdapter(adapter);
    spinner.setOnItemSelectedListener(this);
}

public void onItemSelected(AdapterView<?> arg0, View arg1, int arg2,
        long arg3) {
    // TODO Auto-generated method stub
    switch (arg2) {
    case 0:     
        break;

    case 1:                 
        Intent countdown = new Intent(this, CountdownActivity.class);
        startActivity(countdown);                       
        break;

    default :                       
        break;
    }
}

public void onNothingSelected(AdapterView<?> arg0) {
    // TODO Auto-generated method stub

}

回答1:

Step #1: Get rid of your Spinner.

Step #2: Get rid of your OnItemSelectedListener.

Step #3: Provide your ArrayAdapter as the first parameter to setListNavigationCallbacks().

Step #4: Provide an implementation of ActionBar.OnNavigationListener as the second parameter to setListNavigationCallbacks().

Step #5: In the onNavigationItemSelected() callback method in your ActionBar.OnNavigationListener, do whatever it is you want to do based upon the change in the state of the navigation (e.g., execute a FragmentTransaction).

Step #6: Redesign your application to not start an activity based on this navigation selection, as you are attempting above. Either start the activity from a toolbar button or options menu item, or use fragments to replace (part of) the UI on the existing activity. List and tabs navigation in the action bar is not for launching activities.

来源：https://stackoverflow.com/questions/8662173/how-can-i-add-my-spinner-to-the-actionbar