设置ImageView形状成圆角矩形和纯圆形

<?xml version="1.0" encoding="utf-8"?>
<shape
xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="oval"
android:useLevel="false">
<solid android:color="#66CC00"/>
<size android:width="50dp"
android:height="50dp"/>
</shape>

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
<item android:id="@android:id/background">
<shape>
<corners android:radius="50dip" />
<gradient
android:angle="270"
android:centerColor="#aa3399CC"
android:centerY="0.75"
android:endColor="#aa7476ff"
android:startColor="#aa6699CC"

/>
</shape>
</item>
</layer-list>