Android InsetDrawable

InsetDrawable
A Drawable that insets another Drawable by a specified distance. This is used when a View needs a background that is smaller than the View’s actual bounds.

xml定义如下

<inset xmlns:android="http://schemas.android.com/apk/res/android"
android:drawable="@color/white"
android:insetLeft="8dp"
android:insetRight="8dp" />

inset属性的作用类似边距。
注：使用InsetDrawable为backgroud的View或ViewGroup，其实际内容区大小为显示的drawable区域，不包括inset区域。