imageView显示叠加图：背景是绿色，中间为add图标

<ImageView
    android:id="@+id/iv_add_food"
    android:layout_width="80dp"
    android:layout_height="80dp"
    android:layout_below="@+id/iv_filter"
    android:layout_marginTop="10dp"
    android:padding="16dp"
    android:src="@drawable/layout_food_add_icon"/>   

layout_food_add_icon.xml：叠加两个drawable；针对ic_add_food设置外边距

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:drawable="@drawable/round_rect_r48_00aaa6" />
    <item android:drawable="@drawable/ic_add_food" android:start="7dp" android:end="7dp" android:top="7dp" android:bottom="7dp"/>
</layer-list>

round_rect_r48_00aaa6.xml

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android">
    <solid android:color="@color/color_00aaa6"/>
    <corners android:radius="48dp"/>
</shape>