UICollectionView + iOS 7 / Xcode 5 = Assertion Failure

Question

In my app there was a UICollectionView using flowLayout and it was working beautifully in iOS 6 but fails horribly in iOS 7. As soon as I segue to the view containing my UICollectionView here's what happens:

*** Assertion failure in -[UICollectionView _createPreparedSupplementaryViewForElementOfKind:atIndexPath:withLayoutAttributes:applyAttributes:], /SourceCache/UIKit/UIKit-2903.2/UICollectionView.m:1401
*** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'the view returned from -collectionView:viewForSupplementaryElementOfKind:atIndexPath
(UICollectionElementKindSectionHeader,<NSIndexPath: 0x145f3f50> {length = 2, path = 0 - 0}) was not retrieved by calling -dequeueReusableSupplementaryViewOfKind:withReuseIdentifier:forIndexPath: or is nil'
(<UICollectionReusableView: 0x145f9400; frame = (0 0; 320 20); layer = <CALayer: 0x145f90c0>>)

score 12 · Accepted Answer · answered Oct 01 '13 at 17:21

12

When I updated to iOS 7 I ran into this. The problem ended up being that you shouldn't be so explicit with your dataSource. If you have the following, remove it:

- (UICollectionReusableView *)collectionView:(UICollectionView *)collectionView viewForSupplementaryElementOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath {
    return nil;
}

answered Oct 01 '13 at 17:21

ZaBlanc

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Perfect answer @ZaBlanc, thank you! Any idea what changed from iOS 6 to 7? [The iOS 7 API Diffs](https://t.co/vuiz2TaU3r) don't show anything but additions to UICollectionView – self.name Oct 01 '13 at 23:45

score 6 · Answer 2 · edited Oct 28 '13 at 04:14

It will crash if you return nil in this function:

- (UICollectionReusableView*)collectionView:(UICollectionView *)collectionView viewForSupplementaryElementOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath

Basically, the only reason you would have to return nil is if the "kind" NSString is not a type you expect. In that case, just delete that object in the interface builder. I had this same crash because my collection view had a footer in the interface builder but I was not calling the registerNib code (as bneely described above) to set up a footer. I'd get to the viewForSupplementaryElementOfKind and return nil because it was a kind I was not expecting.(which is guaranteed to cause the crash).

score 1 · Answer 3 · answered Sep 27 '13 at 01:30

You need to register a UINib with your UICollectionView instance:

UINib *nib = [UINib nibWithNibName:@"YourNibNameWithoutExtension" bundle:nil];
[collectionView registerNib:nib forCellWithReuseIdentifier:@"YourReuseIdentifier"];

And create all of your UICollectionViewCell instances via -[UICollectionView dequeueReusableCellWithReuseIdentifier:forIndexPath:].

This comment in Apple's UICollectionView.h explains the requirement:

// The cell that is returned must be retrieved from a call to -dequeueReusableCellWithReuseIdentifier:forIndexPath:
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath;

Thanks @bneely, I was already registering nibs (and classes initially) but it turns out ZaBlanc's answer fixed the mystery crash. Don't ask me how/why because nothing in UICollectionView was really deprecated in the iOS7 API Diffs. — self.name, Oct 02 '13 at 14:49

score 1 · Answer 4 · edited Dec 12 '14 at 08:29

1

I've got this problem, as solved

I think you could check have you check the Section Header in IB Collection View -> Accessories -> Section Header

edited Dec 12 '14 at 08:29

CRABOLO

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answered Jul 14 '14 at 22:12

xmkevinchen

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score 1 · Answer 5 · answered Sep 30 '15 at 16:50

1

I received this by forgetting to set my class to the correct type in interface builder and not wiring up and outlets

answered Sep 30 '15 at 16:50

Adam Waite

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Aha... something like this happened too! Thank you for this comment, it made me check my newly created reusable view.. now the internal inconsistency exception makes sense! :D – Pavan Mar 03 '17 at 07:43

score 0 · Answer 6 · answered Mar 12 '14 at 10:57

0

You get that error because your collection has a header. I got that after adding a header in IB. Remove the header or check the Delegate for header options

answered Mar 12 '14 at 10:57

wolffan

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score 0 · Answer 7 · answered Nov 05 '15 at 10:28

0

Be sure you have set collection view datasource and delegate. In my case this error was being thrown because of it.

answered Nov 05 '15 at 10:28

Marcos Reboucas

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UICollectionView + iOS 7 / Xcode 5 = Assertion Failure

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