##Objectives
- Learn how to write a custom view.
There are two kinds to implement a custom view: use a compound view or extends a normal view.
- Build this simple app using compound view.
- Write an app to simulating drawing on a chalk board.
The image for the board background can be found here
- http://developer.android.com/guide/topics/ui/custom-components.html
- http://developer.android.com/training/custom-views/index.html
- What the difference between
<merge/>
and<include/>
xml tag?