Why isn't my UIViewController in the responder chain for its view?

Question

I have written a subclass of UIViewController which creates a view programmatically, instead of loading it from a NIB file.

It has a simple loadView met

Answer 1

I think the problem is that UIScrollView has a lot of bugs, and workarounds to the bugs, and bugs in the workarounds to the bugs :).

It's complicated by the fact that subclassing UIScrollView is usually a bad idea in the long run - you'll often have to subclass it for other reasons that cannot be solved any other way, so if you want to re-use your code, try not to subclass it until you absolutely have to.

Simplest solution I've found that works consistently is to make your content view a tiny UIView subclass - bearing in mind your content view itself is REQUIRED by UIScrollView to never change (e.g. if you enable zooming - Apple has some bugs up to at least iOS 6 that kick in when you change the content view of an existing scrollview), so it's a good idea to keep it trivial, and put your custom views inside it as subviews.

NB: This has always worked for me, on multiple shipped apps. If there's a problem, I haven't seen it yet. I have no idea why Apple doesn't implement this simple change themselves, unless there's a subtle problem with it that I haven't run into yet!

Usage:

/** Inside your UIViewController, wherever you set the root content view
of your UIScrollView, you have to also tell the custom class "I am the nextResponder!"
*/
-(void)viewDidLoad
{
    self.scrollView.contentSize = self.viewEmbeddedInScrollview.frame.size;
    self.viewEmbeddedInScrollview.nextResponderHeyAppleWhyDidYouStealThis = self;
}

Interface file + class file:

#import 

@interface UIViewThatNeverLosesItsNextResponder : UIView

@property(nonatomic,retain) UIResponder* nextResponderHeyAppleWhyDidYouStealThis;

@end



#import "UIViewThatNeverLosesItsNextResponder.h"

@implementation UIViewThatNeverLosesItsNextResponder

- (id)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
        // Initialization code
    }
    return self;
}

@synthesize nextResponderHeyAppleWhyDidYouStealThis;

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    [nextResponderHeyAppleWhyDidYouStealThis touchesBegan:touches withEvent:event];
}

-(void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event
{
    [nextResponderHeyAppleWhyDidYouStealThis touchesCancelled:touches withEvent:event];
}

-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
    [nextResponderHeyAppleWhyDidYouStealThis touchesEnded:touches withEvent:event];
}

-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
    [nextResponderHeyAppleWhyDidYouStealThis touchesMoved:touches withEvent:event];
}

@end