Question

I have an mainUIView within which there is a customised UIImageView (named myImageView).

In the myImageView.h file, I have declared:

@property (strong, nonatomic) mainViewController *viewController;

and in the myImageView.m file, I have the following codes:

        self.viewController = self.parent;

This lines raises an error indication:
Property ‘parent’ not found on object of type myImageView.

I thought putting the myImageView inside the mainUIView would make the default parent-and-sub relationship, but obviously it’s not so.

In the main storyboard, I tried to Ctrl-drag the myImageView to the mainViewController, but no options pops up for me to select delegate.

Can anyone give me explanation of these please? I’m feeling a bit confused… Many thanks!

Answer 1

As your myImageView is a UIView is has no parent. Is just has a superview which again is a UIView. Basically a view doesn’t know its controller. Although the controller can implement a view’s delegate to get informed about events. So your AppDelegate knows your ViewController and the controller knows your ImageView. The AppDelegates window knows the view of your controller which will most likely contain the whole view hierarchy (except AlertViews, HUDViews, modal views and simmilar…).

I think what you want to do works best implementing the delegate pattern. (see Apple Docs)