Custom control development in iOS [closed]

Question

Is there a guide / book about custom control development for iOS? All the books I've found don't go beyond using UIKit builtin controls.

Answer 1

As @petert wrote, Cocoa Controls is a great resource, but my favourite is by far iDev Recipes (even though it's not updating that often anymore). Check also http://maniacdev.com/, many open source libraries/projects can be found and it gets updated regularly. Ray Wenderlich has also many nice tutorials - scroll down to "Graphics and Animation".

EDIT: I just saw that @Jano suggests idevrecipes as well, sorry for doulbe posting