【起航计划 016】2015 起航计划 Android APIDemo的魔鬼步伐 15 App->Activity->Wallpaper 系统壁纸作为当前Activity的背景

        <activity android:name=".app.WallpaperActivity"
                android:label="@string/activity_wallpaper"
                android:theme="@style/Theme.Wallpaper">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.SAMPLE_CODE" />
            </intent-filter>
        </activity>

    <!-- A theme that has a wallpaper background.  Here we explicitly specify
         that this theme is to inherit from the system‘s wallpaper theme,
         which sets up various attributes correctly. -->
    <style name="Theme.Wallpaper" parent="android:style/Theme.Wallpaper">
        <item name="android:colorForeground">#fff</item>
    </style>