用setAnimationStyle来设置popwindow显示消失的动画效果

popwindow通过setAnimationStyle(int animationStyle)函数来设置动画效果
android:windowEnterAnimation表示进入窗口动画
android:windowExitAnimation表示窗口退出动画

在res/values/style.xml代码：

<?xml version="1.0" encoding="utf-8"?>    
<resources>       
<style name="PopupAnimation" parent="android:Animation" mce_bogus="1">         
        <item name="android:windowEnterAnimation">@anim/popup_enter</item>    
        <item name="android:windowExitAnimation">@anim/popup_exit</item>    
    </style>    
</resources>

在res/anim/popup_enter.xml声明所需进入动画

<?xml version="1.0" encoding="utf-8"?>        
<set xmlns:android="http://schemas.android.com/apk/res/android">    
    <scale android:fromXScale="0.6" android:toXScale="1.0" 
        android:fromYScale="0.6" android:toYScale="1.0" android:pivotX="50%" 
        android:pivotY="50%" android:duration="1000" />    
    <alpha android:interpolator="@android:anim/decelerate_interpolator" 
        android:fromAlpha="0.0" android:toAlpha="1.0" android:duration="1000" />    
</set>

在res/anim/popup_exit.xml声明所需退出动画

<?xml version="1.0" encoding="utf-8"?>    
<set xmlns:android="http://schemas.android.com/apk/res/android">    
    <scale    
        android:fromXScale="1.0" 
        android:toXScale="0.5" 
        android:fromYScale="1.0" 
        android:toYScale="0.5" 
        android:pivotX="50%" 
        android:pivotY="50%" 
        android:duration="500" />    
    <alpha    
        android:interpolator="@android:anim/accelerate_interpolator" 
        android:fromAlpha="1.0" 
        android:toAlpha="0.0" 
        android:duration="500" />    
</set>

设置popwindow的位置及动画

popupWindow.setAnimationStyle(R.style.PopupAnimation);
popupWindow.showAtLocation(findViewById(R.id.parent), Gravity.CENTER| Gravity.CENTER, 0, 0);
popupWindow.update();

调用popupWindow.dismiss();语句。popwindow消失，自动调用消失动画popup_exit.xml