Adding Action Buttons

为简单起见,此处只保留了关键代码。详细过程参见官方教程:Adding Action Buttons

在AndroidManifest.xml文件中,我们有如下代码:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.simon.myapplication"
    android:versionCode="1"
    android:versionName="1.0" >
    <uses-sdk
        android:minSdkVersion="10"
        android:targetSdkVersion="21" />
    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/Theme.AppCompat.Light.DarkActionBar" >
        <activity
            android:name="com.example.simon.myapplication.MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity
            android:name="com.example.simon.myapplication.DisplayMessageActivity"
            android:label="@string/title_activity_actions"
            android:parentActivityName="com.example.simon.myapplication.MainActivity" >
            <meta-data
                android:name="android.support.PARENT_ACTIVITY"
                android:value="com.example.simon.myapplication.MainActivity" />
        </activity>
    </application>
</manifest>

此处,为第二个Acitivity(DisplayMessageActivity)指定了parentAcitivity。

在res/menu/main_activity_actions.xml文件中,我们定义menu如下:

<menu xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto">
    <!-- Search, should appear as action button -->
    <item android:id="@+id/action_search"
        android:icon="@drawable/ic_action_search"
        android:title="@string/action_search"
        app:showAsAction="ifRoom" />
    <!-- Overflow, should appear as action button -->
    <item android:id="@+id/action_overflow"
        android:icon="@drawable/ic_action_overflow"
        android:title="@string/action_overflow"
        app:showAsAction="always" />
</menu>

此处,我们将Search设置为ifRoom(空间足够时显示),Overflow设置为always(总是显示)。

在DisplayMessageActivity类中,有如下代码:

 1 public class DisplayMessageActivity extends ActionBarActivity {
 2 
 3     @Override
 4     protected void onCreate(Bundle savedInstanceState) {
 5         super.onCreate(savedInstanceState);
 6 
 7         // Get the message from the intent
 8         Intent intent = getIntent();
 9         String message = intent.getStringExtra(MainActivity.EXTRA_MESSAGE);
10 
11         // Create the text view
12         TextView textView = new TextView(this);
13         textView.setTextSize(40);
14         textView.setText(message);
15 
16         // Set the text view as the activity layout
17         setContentView(textView);
18 
19         ActionBar actionBar = getSupportActionBar();
20         actionBar.setHomeAsUpIndicator( R.drawable.ic_launcher );
21         actionBar.setDisplayOptions(ActionBar.DISPLAY_HOME_AS_UP
22                 | ActionBar.DISPLAY_SHOW_TITLE );
23     }
24 
25     @Override
26     public boolean onCreateOptionsMenu(Menu menu) {
27         // Inflate the menu; this adds items to the action bar if it is present.
28         getMenuInflater().inflate(R.menu.main_activity_actions, menu);
29         return true;
30     }
31 
32     @Override
33     public boolean onOptionsItemSelected(MenuItem item) {
34         // Handle presses on the action bar items
35         switch (item.getItemId()) {
36             case R.id.action_search:
37                 Log.d( "MyApp", "action_search" );
38                 return true;
39             case R.id.action_overflow:
40                 Log.d( "MyApp", "action_overflow" );
41                 return true;
42             default:
43                 return super.onOptionsItemSelected(item);
44         }
45 
46     }
47 }

注:1) 在onCreateOptionsMenu函数中,将main_activity_actions.xml定义的action添加到action bar中。

       2) 在onOptionsItemSelected函数中,定义响应action bar中的某个action被选中时的代码。

       3) 19~22行(onCreate函数中),用于将默认的左键头替换成R.drawable.ic_launcher图标,即,使用图标代替默认的左键头,作为返回上级页面的按钮。

效果图如下:

 

posted on 2015-02-03 22:15  游不动の鱼  阅读(188)  评论(0编辑  收藏  举报