Android ActionBar下拉选项

package com.example.actionBarTest.actionBarList;

import android.app.ActionBar;

import android.app.Activity;

import android.app.Fragment;

import android.os.Bundle;

import android.widget.ArrayAdapter;

import android.widget.SpinnerAdapter;

import com.example.actionBarTest.R;

import java.util.ArrayList;

import java.util.List;

/**

 * Created by Heyiyong on 2014-5-2 上午9:50.

 */

public class ListNavigationActivity extends Activity implements ActionBar.OnNavigationListener {

    private List<Fragment> fragments;

    private String[] navs = {"添加", "删除", "编辑", "查询", "更多"};

    private SpinnerAdapter spinnerAdapter;

    public void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.tab_main);

        spinnerAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, navs);

        HomeFragment homeFragment = new HomeFragment();

        MusicFragment musicFragment = new MusicFragment();

        VideoFragment videoFragment = new VideoFragment();

        fragments = new ArrayList<Fragment>();

        fragments.add(homeFragment);

        fragments.add(musicFragment);

        fragments.add(homeFragment);

        fragments.add(videoFragment);

        fragments.add(homeFragment);

        ActionBar actionBar = getActionBar();

        if (actionBar != null) {

            actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_LIST);

            actionBar.setListNavigationCallbacks(spinnerAdapter, this);

        }

    }

    @Override

    public boolean onNavigationItemSelected(int itemPosition, long itemId) {

        System.out.println("itemPosition = " + itemPosition);

        getFragmentManager().beginTransaction().replace(R.id.tab_main, fragments.get(itemPosition)).commit();

        return true;

    }

}

actionBar.setListNavigationCallbacks(spinnerAdapter, this);
这个ArrayAdapter是继承于BaseAdapter的，而BaseAdapter又实现了SpinnerAdapter接口.