custom draw android scrollview

Question

i am trying to do a custom view in android. i want to draw a image on top and then down to that rest of the screen a scrollable draw text.

thats why i did a xml layout and the custom view inside a scrollview beneath imageview

but for some reason the ondraw is not called. if i do setContentlayout(new CustomView(this)), it calls onDraw but scrollview effect is not achieved.

any example ?