1.         ActionBar是一个显示在屏幕顶部的控件，它包括了在左边显示的应用的logo图标和右边操作菜单的可见项。
2.        我们可以选择可见的操作菜单可见项，不可见项会以下拉列表的形式呈现出来。（见上图相机图标右侧，点击出现下拉列 表，显示没有直接显示出来的操作菜单可见项）
3.        ActionBar为Fragment之间提供标签导航

1.      不需要导入ActionBar，因为在android3.0或者以上版本中，ActionBar已经默认的包含在Activity中
2.      在Android3.0的默认主题“holographic”中，已经创造了ActionBar
3.      当android:minSdkVersion 或者 android:targetSdkVersion 属性被设置成11或者更高时，应用会被认为是Android3.0版本（默认含有ActionBar）

1.      我们可以通过把主题设置为Theme.Holo.NoActionBar为一个Activity去除掉ActionBar。                                                                                        <activity android:theme="@android:style/Theme.Holo.NoActionBar">
2.      我们也可以通过在代码中调用show()或者hide()方法来相应的显示或者隐藏ActionBar

public class ActionBarDemoActivity extends Activity
{/** Called when the activity is first created. */@Overridepublic void onCreate(Bundle savedInstanceState){super.onCreate(savedInstanceState);setContentView(R.layout.main);Button showBt = (Button) findViewById(R.id.showBt);showBt.setOnClickListener(new OnClickListener(){public void onClick(View view){ActionBar actionBar = getActionBar();actionBar.show();}});}public boolean onCreateOptionsMenu(Menu menu){super.onCreateOptionsMenu(menu);MenuItem add = menu.add(0, 1, 0, "Save");MenuItem open = menu.add(0, 2, 1, "Open");MenuItem close = menu.add(0, 3, 2, "Close");add.setShowAsAction(MenuItem.SHOW_AS_ACTION_IF_ROOM);open.setShowAsAction(MenuItem.SHOW_AS_ACTION_IF_ROOM);close.setShowAsAction(MenuItem.SHOW_AS_ACTION_IF_ROOM);return true;}
}

public class ActionBarXMLActivity extends Activity {/** Called when the activity is first created. */@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.main);}@Overridepublic boolean onCreateOptionsMenu(Menu menu){MenuInflater inflater = getMenuInflater();inflater.inflate(R.menu.optionsmenu, menu);return true;}
}

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android" ><itemandroid:id="@+id/item1"android:orderInCategory="1"android:showAsAction="ifRoom|withText"android:title="@string/save"/><itemandroid:id="@+id/item2"android:orderInCategory="2"android:showAsAction="ifRoom|withText"android:title="@string/edit"/><itemandroid:id="@+id/item3"android:orderInCategory="3"android:showAsAction="ifRoom|withText"android:title="@string/about"/><itemandroid:id="@+id/item4"android:orderInCategory="4"android:showAsAction="ifRoom|withText"android:title="@string/help"/><itemandroid:id="@+id/item5"android:orderInCategory="5"android:showAsAction="ifRoom|withText"android:title="@string/file"/><itemandroid:id="@+id/item6"android:orderInCategory="6"android:showAsAction="ifRoom|withText"android:title="@string/run"/><itemandroid:id="@+id/item7"android:orderInCategory="7"android:showAsAction="ifRoom|withText"android:title="@string/source"/><itemandroid:id="@+id/item8"android:orderInCategory="8"android:showAsAction="ifRoom|withText"android:title="@string/navigate"/><itemandroid:id="@+id/item9"android:orderInCategory="9"android:showAsAction="ifRoom|withText"android:title="@string/search"/><itemandroid:id="@+id/item10"android:orderInCategory="10"android:showAsAction="ifRoom|withText"android:title="@string/project"/><itemandroid:id="@+id/item11"android:orderInCategory="11"android:showAsAction="ifRoom|withText"android:title="@string/refactor"/><itemandroid:id="@+id/item12"android:orderInCategory="12"android:showAsAction="ifRoom|withText"android:title="@string/window"/><itemandroid:id="@+id/item13"android:orderInCategory="13"android:showAsAction="ifRoom|withText"android:title="@string/help"/></menu>

使用带字的Action Item

Action事件

应用图标

@Overridepublic boolean onOptionsItemSelected(MenuItem item){switch (item.getItemId()){case android.R.id.home:Intent intent = new Intent(this, MainActivity.class);intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);startActivity(intent);return true;default:return super.onOptionsItemSelected(item);}}

public class HomyUpActivity extends Activity {/** Called when the activity is first created. */@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.main);}@Overrideprotected void onStart() {super.onStart();ActionBar actionBar = this.getActionBar();actionBar.setDisplayHomeAsUpEnabled(true);}@Overridepublic boolean onCreateOptionsMenu(Menu menu) {MenuInflater inflater = getMenuInflater();inflater.inflate(R.menu.optionsmenu, menu);return true;}}

添加活动视图

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android" ><itemandroid:id="@+id/item4"android:orderInCategory="4"android:showAsAction="ifRoom|withText"android:title="@string/help"/><itemandroid:id="@+id/item5"android:orderInCategory="5"android:showAsAction="ifRoom|withText"android:title="@string/file"/><itemandroid:id="@+id/search"android:actionViewClass="android.widget.SearchView"android:showAsAction="ifRoom"android:title="Search"/></menu>

public class HomyUpActivity extends Activity {/** Called when the activity is first created. */@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.main);}@Overrideprotected void onStart() {super.onStart();ActionBar actionBar = this.getActionBar();actionBar.setDisplayHomeAsUpEnabled(true);}@Overridepublic boolean onCreateOptionsMenu(Menu menu){MenuInflater inflater = getMenuInflater();inflater.inflate(R.menu.optionsmenu, menu);return true;}
}

1.         ActionBar可以现实选项卡供用户切换浏览该Activity中不同的Fragment
2.         每个标签都可以是一个图标或文本标题
   
   

public class TabsActivity extends Activity
{/** Called when the activity is first created. */@Overridepublic void onCreate(Bundle savedInstanceState){super.onCreate(savedInstanceState);setContentView(R.layout.main);ActionBar bar = getActionBar();bar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);ActionBar.Tab tabA = bar.newTab().setText("A Tab");ActionBar.Tab tabB = bar.newTab().setText("B Tab");ActionBar.Tab tabC = bar.newTab().setText("C Tab");Fragment fragmentA = new AFragmentTab();Fragment fragmentB = new BFragmentTab();Fragment fragmentC = new CFragmentTab();}tabA.setTabListener(new MyTabsListener(fragmentA));tabB.setTabListener(new MyTabsListener(fragmentB));tabC.setTabListener(new MyTabsListener(fragmentC));bar.addTab(tabA);bar.addTab(tabB);bar.addTab(tabC);protected class MyTabsListener implements ActionBar.TabListener{private Fragment fragment;public MyTabsListener(Fragment fragment){this.fragment = fragment;}@Overridepublic void onTabSelected(Tab tab, FragmentTransaction ft){ft.add(R.id.fragment_place, fragment, null);}}}

public class AFragmentTab extends Fragment
{@Overridepublic View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState){return inflater.inflate(R.layout.fragment_a, container, false);}
}

public class BFragmentTab extends Fragment
{@Overridepublic View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState){return inflater.inflate(R.layout.fragment_b, container, false);}
}

public class CFragmentTab extends Fragment
{@Overridepublic View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState){return inflater.inflate(R.layout.fragment_c, container, false);}
}

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"android:layout_width="fill_parent"android:layout_height="fill_parent"android:orientation="vertical" ><LinearLayoutandroid:id="@+id/fragment_place"android:layout_width="match_parent"android:layout_height="wrap_content" ></LinearLayout></LinearLayout>