使用Style实现的popwindow弹出和收起的动画效果

<!--系统级theme下设置 actionbar下拉菜单的弹出动画 -->
<style name="TestTheme" parent="@android:style/Theme.Holo.Light">
<item name="android:popupAnimationStyle">@style/MyPopupMenuAnimaiton</item>
</style>

<style name="MyPopupMenuAnimaiton" parent="android:Animation">
<item name="android:windowEnterAnimation">@anim/circles_actionbar_pop</item>
<item name="android:windowExitAnimation">@anim/circles_actionbar_pop</item>
</style>

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android" >
<scale
android:duration="250"
android:fillAfter="false"
android:fromXScale="0.0"
android:fromYScale="0.0"
android:interpolator="@android:anim/accelerate_decelerate_interpolator"
android:pivotX="100%"
android:pivotY="0%"
android:toXScale="1.0"
android:toYScale="1.0" />
</set>

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android" >
<scale
android:duration="250"
android:fillAfter="false"
android:fromXScale="1.0"
android:fromYScale="1.0"
android:interpolator="@android:anim/accelerate_decelerate_interpolator"
android:pivotX="100%"
android:pivotY="0%"
android:toXScale="0.0"
android:toYScale="0.0" />
</set>