<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:innerRadius="0dp"
android:shape="oval"
android:thickness="140dp"
android:useLevel="false">
<gradient
    android:angle="0"
    android:centerX="0"
    android:startColor="@android:color/holo_green_light"
    android:endColor="@android:color/darker_gray"
    android:type="sweep" />

<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="oval">

<gradient
    android:centerX="-1"
    android:type="sweep"
    android:startColor="#fff"
    android:endColor="#000"
    />

</shape>