One ViewController vs. many ViewControllers - iphone

Question

I'm building an app which consists of different views which are closely related to each other. So far, I only have one UIViewController which controls these different views. View 1 and 2 share the same background, for instance, and the transition between view 1 and 2 is a custom animation.
My problem is that both view 1 and 2 have an UIScrollView. My UIViewController is their delegate and I could have the following scrollViewDidScroll to distinguish between the two scrollviews:
- (void)scrollViewDidScroll:(UIScrollView *)scrollView {
if (scrollView.tag == 1)
//handle a
else if (scrollView.tag == 2)
//handle b
else if (scrollView.tag == 3)
//handle c
}
As a lot happens with scrollView 1 and different things happen with scrollView2, the code will become really messy. Ideally, I'd like to define in a separate file what happens if scrollView1 is scrolled etc.. Yet I don't want to have another UIViewController as then transitions become more difficult. I don't have a NavBar or ToolBar, so neither UINavigationController nor UITabBarController would work very well in my case.
What should I do?
I posted a similar question here.

Answer 1

If you don't want two view controllers, just create a separate delegate for each scroll view. Make it an NSObject which conforms to UIScrollViewDelegate and create it at the same time as the scroll view.
Seems to combine the results you seek: one view controller, but encapsulated scroll view code.

Answer 2

You could have a base controller class that handles the common functionality. Each different controller can inherit from this and override with their specific functionality as required.
Aka the template pattern
Edit
To expand. You say you want only one view controller. So you should create a separate class to handle the individual functionality. The View Controller has a base class pointer which gets swapped around according to the current view.
In pseudo code :
class BaseFunctionality
-(void) handleDidScroll {}
end
class ScrollViewAFunctionality : BaseFunctionality
-(void) handleDidScroll {
// Lots of interesting technical stuff...
}
end
class ScrollViewBFunctionality : BaseFunctionality
-(void) handleDidScroll {
// Lots of interesting technical stuff...
}
end
class TheViewController : UIViewController
BaseFunctionality *functionality;
-(void) swapViews {
// Code to swap views
[this.functionality release];
if (view == A)
this.functionality = [[ScrollViewAFunctionality alloc] init]
else if ( view == B)
this.functionality = [[ScrollViewBFunctionality alloc] init]
}
- (void)scrollViewDidScroll:(UIScrollView *)scrollView {
[this.functionality handleDidScroll];
}
end