error: Error parsing XML: unbound prefix
<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">
<alpha
android:interpolator="@android:anim/accelerate_interpolator"
android:fromAlpha="1.0"
android:toAlpha="0.0"
android:duration="100" />
</set>
忘了没有加入 xmlns:android="http://schemas.android.com/apk/res/android"