Action Bar的使用

提示：Android官网的Trainning中有Action Bar的使用教程

使用步骤（兼容低版本）

一、添加Action Bar

1. Action Bar在Android3.0（API 11）被引入，要兼容2.1以上版本，需要引入v7库（含有版本不同的v4包，需要把版本较低的包删掉）

2. 将继承的Activity改为ActionBarActivity（ActionBarActivity继承了FragmentActivity）

3. 主题改为 "Theme.AppCompat.Light"（引入v7包才有这个主题）

二、 添加搜索按钮

1. 搜索按钮配置

<menu xmlns:android="http://schemas.android.com/apk/res/android"
      xmlns:yourapp="http://schemas.android.com/apk/res-auto" ><span style="color:#3333FF;"><!-- 兼容2.x要加上这个命名空间 --></span>
    <!-- Search, should appear as action button -->
    <item android:id="@+id/action_search"
          android:icon="@drawable/ic_action_search"
          android:title="@string/action_search"
          yourapp:showAsAction="ifRoom"
          yourapp:actionViewClass="android.support.v7.widget.SearchView" /><span style="color:#3333FF;"><!-- 兼容2.x要用v7里的SearchView --></span>
</menu>

2. 实现搜索功能

在API Demos / App / Action Bar / Action Bar Usage 中可看到搜索功能的实现效果，导入API Demos项目，参考它的代码即可。

• eclipse如何导入API Demos？

         鼠标右击-->New-->Other-->Android Sample Project-->随便勾选一个Android x.x-->next-->ApiDemos-->Finish

              

照抄代码

	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
          getMenuInflater().inflate(R.menu.main, menu);
	    //安卓3.0(API 11)以上
//	    SearchView searchView = (SearchView) menu.findItem(R.id.action_search).getActionView();
            //SearchView兼容低版本方法
	    SearchView searchView = (SearchView) MenuItemCompat.getActionView(menu.findItem(R.id.action_search));
        searchView.setOnQueryTextListener(this);
	    return true;
	}
 <pre name="code" class="java">        //处理ActionBar菜单条目点击事件
	@Override
	public boolean onOptionsItemSelected(MenuItem item) {
	    switch (item.getItemId()) {
	        case R.id.action_search:
	        	Toast.makeText(getApplicationContext(), "搜索", 0).show();
	            return true;
	    }
	    return super.onOptionsItemSelected(item);
	}

	//当搜索提交时
	@Override
	public boolean onQueryTextSubmit(String query) {
		Toast.makeText(this, "Searching for: " + query + "...", Toast.LENGTH_SHORT).show();
		return true;//true表示要执行这个方法
	}
	//当文本发生变化时
	@Override
	public boolean onQueryTextChange(String newText) {
		Toast.makeText(this, "Searching for: " + newText + "...", Toast.LENGTH_SHORT).show();
		return true;//true表示要执行这个方法
	}

三、设置返回按钮

当我们从主页跳转到其他页面时，点击按钮（箭头）可以返回主页

1. 添加返回按钮

              //ActionBar actionBar = getActionBar();//android3.0以上
		ActionBar actionBar = getSupportActionBar();//兼容2.x
		actionBar.setDisplayHomeAsUpEnabled(true);

2. 处理返回按钮点击事件（两种方法）

方法一

        @Override
	public boolean onOptionsItemSelected(MenuItem item) {
		if(item.getItemId() == android.R.id.home){ //返回按钮的id是android.R.id.home
			finish();
		}
	    return super.onOptionsItemSelected(item);
	}

方法二（AndroidManifest.xml里配置）

      要点：(1)<activity>中设置属性parentActivityName，指定要返回的页面；(2)配置<meta-data>来兼容4.0以下版本

    <!-- The main/home activity (it has no parent activity) -->
    <activity
        android:name="com.example.myfirstapp.MainActivity" ...>
        ...
    </activity>
    <!-- A child of the main activity -->
    <activity
        android:name="com.example.myfirstapp.DisplayMessageActivity"
        android:label="@string/title_activity_display_message"
        android:parentActivityName="com.example.myfirstapp.MainActivity" >
        <!-- Parent activity meta-data to support 4.0 and lower -->
        <meta-data
            android:name="android.support.PARENT_ACTIVITY"
            android:value="com.example.myfirstapp.MainActivity" />
    </activity>

四、添加标签栏

1. 配置actionBar标签指针

res/drawable/actionbar_tab_indicator.xml

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">

<!-- STATES WHEN BUTTON IS NOT PRESSED -->

    <!-- Non focused states -->
    <item android:state_focused="false" android:state_selected="false"
          android:state_pressed="false"
          android:drawable="@drawable/tab_unselected" />
    <item android:state_focused="false" android:state_selected="true"
          android:state_pressed="false"
          android:drawable="@drawable/tab_selected" />

    <!-- Focused states (such as when focused with a d-pad or mouse hover) -->
    <item android:state_focused="true" android:state_selected="false"
          android:state_pressed="false"
          android:drawable="@drawable/tab_unselected_focused" />
    <item android:state_focused="true" android:state_selected="true"
          android:state_pressed="false"
          android:drawable="@drawable/tab_selected_focused" />

<!-- STATES WHEN BUTTON IS PRESSED -->

    <!-- Non focused states -->
    <item android:state_focused="false" android:state_selected="false"
          android:state_pressed="true"
          android:drawable="@drawable/tab_unselected_pressed" />
    <item android:state_focused="false" android:state_selected="true"
        android:state_pressed="true"
        android:drawable="@drawable/tab_selected_pressed" />

    <!-- Focused states (such as when focused with a d-pad or mouse hover) -->
    <item android:state_focused="true" android:state_selected="false"
          android:state_pressed="true"
          android:drawable="@drawable/tab_unselected_pressed" />
    <item android:state_focused="true" android:state_selected="true"
          android:state_pressed="true"
          android:drawable="@drawable/tab_selected_pressed" />
</selector>

2.. 重新配置主题

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <!-- the theme applied to the application or activity -->
    <style name="CustomActionBarTheme"
           parent="@style/Theme.AppCompat.Light">
        <!-- <item name="android:actionBarTabStyle">@style/MyActionBarTabs</item> 3.0以上 -->

        <!-- Support library compatibility -->
        <item name="actionBarTabStyle">@style/MyActionBarTabs</item>
    </style>

    <!-- ActionBar tabs styles -->
    <style name="MyActionBarTabs"
           parent="@style/Widget.AppCompat.ActionBar.TabView">
        <!-- tab indicator -->
        <item name="android:background">@drawable/actionbar_tab_indicator</item> <!-- 使用步骤1配置的标签指针 -->

        <!-- Support library compatibility -->
        <item name="background">@drawable/actionbar_tab_indicator</item>
    </style>
</resources>

3. 使用这个主题

<application
        android:theme="@style/CustomActionBarTheme" >

4. 自定义PagerAdapter继承FragmentStatePagerAdapter (比PagerAdapter方便)

private class MainAdapter extends FragmentStatePagerAdapter{

      public MainAdapter(FragmentManager fm) {
	  super(fm);
      }

      //每个条目返回的fragment
      @Override
      public Fragment getItem(int arg0) {
    	 return new MyFragment();	
      }

      @Override
      public int getCount() {
	 return mActionBar.getTabCount();
      }
		
}

5. 让标签栏与ViewPager建立关系

• PS： ActionBarActivity已经继承了FragmentActivity，所以可以使用getSupportFragmentManager()等方法
  

ViewPager mViewPager = (ViewPager) findViewById(R.id.vp);
<pre name="code" class="java">ActionBar mActionBar = getSupportActionBar();//3.0以上可用getActionBar() 
mActionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);//添加标签栏
Tab tab1 = mActionBar.newTab().setText("TAB1").setTabListener(listener);
Tab tab2 = mActionBar.newTab().setText("TAB2").setTabListener(listener);
Tab tab3 = mActionBar.newTab().setText("TAB3").setTabListener(listener);
mActionBar.addTab(tab1);//添加标签
mActionBar.addTab(tab2);
mActionBar.addTab(tab3);

mViewPager.setAdapter(new MainAdapter(getSupportFragmentManager()));
    mViewPager.setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener(){ //SimpleOnPageChangeListener比OnPageChangeListener简单方便
       @Override
       public void onPageSelected(int position) {
            mActionBar.setSelectedNavigationItem(position);
       }
});

五、添加可滑动的标签栏（PagerTabStrip）

• PagerTabStrip 可交互的（能被点击）

• PagerTitleStrip 非交互的（不能被点击）

1. 添加PagerTabStrip布局

<android.support.v4.view.ViewPager
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/pager"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <android.support.v4.view.PagerTabStrip
        android:id="@+id/pager_title_strip"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="top"
        android:background="#33b5e5"
        android:textColor="#fff"
        android:paddingTop="4dp"
        android:paddingBottom="4dp" />

</android.support.v4.view.ViewPager>

2. adapter里设置标签title

       private class MainAdapter extends FragmentStatePagerAdapter{           
          @Override
          public int getCount() {
             return 3; // 标签个数
          }

          // 每个标签的标题
          @Override
          public CharSequence getPageTitle(int position) { 
             return "标签" + (position + 1);
          }
       }