ActionBar使用方法 - Android活动栏(二)

  三、添加标签 Tabs

   在ActionBar中实现标签页可以实现android.app.ActionBar.TabListener ，重写onTabSelected、onTabUnselected和onTabReselected方法来关联Fragment。代码如下

private class MyTabListener implements ActionBar.TabListener { 
    private TabContentFragment mFragment; 
 
    // Called to create an instance of the listener when adding a new tab 
    public TabListener(TabContentFragment fragment) { 
        mFragment = fragment; 
    } 
 
    @Override 
    public void onTabSelected(Tab tab, FragmentTransaction ft) { 
        ft.add(R.id.fragment_content, mFragment, null); 
    } 
 
    @Override 
    public void onTabUnselected(Tab tab, FragmentTransaction ft) { 
        ft.remove(mFragment); 
    } 
 
    @Override 
    public void onTabReselected(Tab tab, FragmentTransaction ft) { 
        // do nothing 
    } 
 
} 接下来我们创建ActionBar在Activity中，代码如下
  @Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.main); 
 
    final ActionBar actionBar = getActionBar();  //Android开发网提示getActionBar方法一定在setContentView后面
    actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS); 
    actionBar.setDisplayOptions(0, ActionBar.DISPLAY_SHOW_TITLE); 
 
    Fragment artistsFragment = new ArtistsFragment(); 
    actionBar.addTab(actionBar.newTab().setText(R.string.tab_artists) 
            .setTabListener(new TabListener(artistsFragment))); 
 
    Fragment albumsFragment = new AlbumsFragment(); 
    actionBar.addTab(actionBar.newTab().setText(R.string.tab_albums) 
            .setTabListener(new TabListener(albumsFragment))); 
} 四、添加下拉导航 Drop-down Navigation
 创建一个SpinnerAdapter提供下拉选项，和Tab方式不同的是Drop-down只需要修改下setNavigationMode的模式，将ActionBar.NAVIGATION_MODE_TABS改为ActionBar.NAVIGATION_MODE_LIST，最终改进后的代码为
ActionBar actionBar = getActionBar(); 
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_LIST);You should perform this during your activity's onCreate() method.actionBar.setListNavigationCallbacks(mSpinnerAdapter, mNavigationCallback);
 上面我们通过setListNavigationCallbacks方法绑定一个SpinnerAdapter控件，具体的OnNavigationListener代码示例为
  mOnNavigationListener = new OnNavigationListener() { 
 
  String[] strings = getResources().getStringArray(R.array.action_list); 
 
  @Override 
  public boolean onNavigationItemSelected(int position, long itemId) { 
 
    ListContentFragment newFragment = new ListContentFragment(); 
    FragmentTransaction ft = openFragmentTransaction(); 
  
    ft.replace(R.id.fragment_container, newFragment, strings[position]); 
 
    ft.commit(); 
    return true; 
  } 
};而其中的ListContentFragment的代码为
 public class ListContentFragment extends Fragment { 
    private String mText; 
 
    @Override 
    public void onAttach(Activity activity) { 

      super.onAttach(activity); 
      mText = getTag(); 
    } 
 
    @Override 
    public View onCreateView(LayoutInflater inflater, ViewGroup container, 
            Bundle savedInstanceState) { 

        TextView text = new TextView(getActivity()); 
        text.setText(mText); 
        return text; 
    } 
}

 有关Android ActionBar的四种方式我们已经大概了解，具体的示例工程代码，明天Android开发网继续解析。