I am trying to subclass UIView but I get an error message while trying to compile. I click on File -> New -> File..., then I click on Objective-C class. I click on Next. After Class I type DrawingView. I click on Next. I click on Create. The two files are generated. Then I get the error message that the compiler cannot find <UIKit/UIKit.h>. Why cannot it find it? Did I forget to install someting?