drawble文件夹下面新建，xxx.xml内容如下

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="rectangle">
    <gradient
        android:angle="200"
        android:centerColor="#EBFDEF"
        android:endColor="#EBFDEF"
        android:startColor="#A3FCB5" />
    <corners android:radius="30dp" />
</shape>

效果如下图

如果说，我只要下面两个是圆角，这样就可以

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="rectangle">
    <gradient
        android:angle="200"
        android:centerColor="#EBFDEF"
        android:endColor="#EBFDEF"
        android:startColor="#A3FCB5" />
    <corners
        android:topLeftRadius="0dp"
        android:topRightRadius="0dp"
        android:bottomRightRadius="20dp"
        android:bottomLeftRadius="20dp"
        />

</shape>