笔记：配置父Activity

<application ... >
    ...
    <activity
        android:name="com.example.myfirstapp.DisplayMessageActivity"
        android:label="@string/title_activity_display_message"
        android:parentActivityName="com.example.myfirstapp.MainActivity" >
        <meta-data
            android:name="android.support.PARENT_ACTIVITY"
            android:value="com.example.myfirstapp.MainActivity" />
    </activity>
</application>

The android:parentActivityName attribute declares the name of this activity's parent activity within the app's logical hierarchy. The system uses this value to implement default navigation behaviors, such as Up navigationon Android 4.1 (API level 16) and higher. You can provide the same navigation behaviors for older versions of Android by using the Support Library and adding the <meta-data> element as shown here.