Pattern Locking in android

i want to implement pattern locking in my app, so that user开发者_StackOverflow社区 has to draw a pattern before using the application.

Can anyone suggest me how to do that?

Refer to this link. I tested it and it is a very good example.

I've been thinking of building this myself and i have some idea's.
One thing you could do is just extend the View class and draw the everything in the onDraw() method and handle input in the onTouchEvent() method.