UIButton inside UIView inside UIScrollview, ARC issue

Question

This is an iOS5 and ARC specific question.

I was setting up a set of UIViews inside a UIScrollView, each with their own UIButton declared inside the UIView class:

      IBOutlet UIButton*button;
      @property(nonatomic,strong) UIButton*button;

(I also original had this as a retain instead of strong, but it made no difference)

I also synthesize the button and hook it up in IB to:

      -(IBAction)showArticle:(id)sender;

I add them all to the scroll view with a big loop, depending on the type of article:

       NewsScrollLead*view = [[NewsScrollLead alloc]initWithNibName:@"NewsScrollLead"  bundle:nil];

       [view.view setFrame:CGRectMake(0, 0, 513, 225)];
       [view.titleLabel setText:[newsDict objectForKey:@"title"]];
       [view.details setText:[self flattenHTML:[newsDict objectForKey:@"description"]]];
       [view.source setText:[newsDict objectForKey:@"author"]];

       [view.details setFont:[UIFont fontWithName:@"HelveticaNeue-Condensed" size:14]];
       [view.titleLabel setFont:[UIFont fontWithName:@"HelveticaNeue-BoldCond" size:20]];
       [view.source setFont:[UIFont fontWithName:@"HelveticaNeue-Condensed" size:14]];

       [self.newsScrollView addSubview:view.view];

This is one example of how a view is created and added to the scroll view.

When I try to click on a button, I get an unrecognized selector error from something different each time, not a UIButton. Using NSZombie, the button has been deallocated for some reason.

Any ideas? Pre-iOS5 issues of the same type were resolved by retaining the UIButton, or the view it was contained in, but with ARC there is no retain available.

A temporary fix I've found is to add the buttons programmatically like so: UIButton *button = [[UIButton alloc]initWithFrame:CGRectMake(0, 0, view.view.frame.size.width, view.view.frame.size.height)]; [button setTag:i]; [button addTarget:self action:@selector(presentArticle:) forControlEvents:UIControlEventTouchUpInside]; [view.view addSubview:button]; [view setButton:button]; This fixes the issue, the buttons are never dealloc'd, but is not a true answer to the question. — Matt Foley
Are you sure it's the button that is being deallocated? That doesn't really make sense. It looks to me like your NewsScrollLead view controller (the target of the button?) might be deallocated in what you've shown. What is the unrecognized selector in the error? And what is the UIView subclass (NewsScrollLead looks like a UIViewController subclass)? — Firoze Lafeer
It looks to me like the NewsScrollLead*view that you create is not being held onto anywhere so this could be what is being released. Add an array to your class and add these to the array so that you are maintaining handles to them and see if that solves the issue. — Scott Sherwood

Rikkles Rikkles · Accepted Answer · 2013-02-28T10:07:40

You have the following: - a NewsScrollLead object called view (let's call it N) - inside N there's among other things a view (let's call it V) - inside N there's also a UIButton B - you then add to self.newsScrollView the view V

What happened to N? Well, it got deallocated because it's never used. Therefore B got deallocated as well. The only remaining item is V.

Your problem is that you created V which is useless. Stay with N and add it to self.newsScrollView. Why need a V inside N? Alternatively, if you do need N to store all sorts of items, then N should be an NSObject (not an NSView), and self should have an array property to store all the N objects you created.

UIButton inside UIView inside UIScrollview, ARC issue

1 Answers