问题
These two terms occur in many places but what exactly do they mean in the context of Android animations?
回答1:
The pivotX and pivotY is the central point of the animation.
So for example if you want to do Zoom In animation you can use this
<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android"
android:fillAfter="true" >
<scale
xmlns:android="http://schemas.android.com/apk/res/android"
android:duration="1000"
android:fromXScale="1"
android:fromYScale="1"
android:pivotX="50%"
android:pivotY="50%"
android:toXScale="3"
android:toYScale="3" >
</scale>
</set>
and the android:pivotX="50%" and android:pivotY="50%" will mean the zoom will be started from the center.
There is also a nice tutorial by android hive here
来源：https://stackoverflow.com/questions/26523380/what-do-pivotx-and-pivoty-mean-in-android-animations