1、This view is based on someone other's idea.The core of the idea is that we change the view by "onLayout" rather than by "onDraw".
2、Some list like RecyclerView uses scrap and recycler to cache views.However this view doesn't cache view,it only cache data.it means that we can't change the image of it's view.
This view is not easy to change.So,it is just a view with high coupling.You should understand the view before using it.