Shape添加阴影效果

https://blog.youkuaiyun.com/sinat_31057219/article/details/76663900

阴影
<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
    <!-- 灰色阴影 -->
    <item
        android:left="2dp"
        android:top="2dp"
        >
        <shape>
            <solid android:color="@android:color/darker_gray" />
            <corners android:radius="10dp" />
        </shape>
    </item>
    <!-- 白色前景 -->
    <item
        android:bottom="4dp"
        android:right="4dp"
        android:top="4dp"
        android:left="4dp"
        >
        <shape>
            <solid android:color="#FFFFFF" />
            <corners android:radius="10dp" />
        </shape>
    </item>
</layer-list>