Inheritance and additional graphics TextView

I inherited TextView write a class, when the trigger click event, I want to vertex TextView bottom right corner as the origin of painting a quarter circle, ask them how great God realization?
Reply:
The landlord must be so achieved? You can open a new path ah
TextView and ImageView overlap (ImageView slightly larger), ImageView is the fourth round you, when clicked, displays the imageView not to ok it?
Reply:

cited a floor ncepu307 reply:

landlord must be so achieved? You can open a new path ah
TextView and ImageView overlap (ImageView slightly larger), ImageView is the fourth round you, when clicked, displays the imageView not to ok it?

Ah so you can, I have a question that I can not save the Canvas object onDraw systematic approach to, I need to add graphics when I re-use the back of the Canvas object to draw?