Android Drawable各种定义方式

1、利用shape

<?xml version="1.0" encoding="utf-8"?><rotate xmlns:android="http://schemas.android.com/apk/res/android"    android:fromDegrees="0"        android:pivotX="50%"    android:pivotY="50%"           android:toDegrees="360" >      <shape android:shape="ring"         android:innerRadiusRatio="3"        android:thicknessRatio="15"        android:useLevel="false">                <!-- 扫描渐变 -->        <gradient             android:type="sweep"            android:useLevel="false"             android:startColor="#222222"            android:centerColor="#666666"            android:endColor="#ffffff"            android:centerX="0.5"            android:centerY="0.5" />    </shape>  </rotate>