Assertion Failure in UICollectionViewData validateLayoutInRect on ios7

Question

Assertion Failure in UICollectionViewData validateLayoutInRect on iOS7.

I am trying to delete all UICollectionView items, one by one, using a for loop; I posted my code below. I delete the UICollectionView items using deleteItemsAtIndexPaths. It's working perfectly on iOS6, but crashes in iOS7 with this exception:

Assertion Failure in UICollectionViewData validateLayoutInRect

I delete the object from collectionArray then self.collectionView, one by one, using indexPath. When I delete the 4th object its raises Assertion failure on iOS7. Here I am using performBatchUpdates.

Please help me get the proper result in iOS7. Share proper code. Thanks in advance.

try  {         for (int i=count-1; i>=0; i--)  {           [self.collectionView performBatchUpdates:^(void){               [collectionArray removeObjectAtIndex:i]; // First delete the item from you model                [self.collectionView deleteItemsAtIndexPaths:@[[NSIndexPath indexPathForRow:i inSection:0]]];           } completion:nil];         [self.collectionView reloadData];     } } @catch (NSException *exception) { } @finally { } 

Answer 1

I actually got this crash one time not because I was returning zero for a number of sections or items in a section but because I was reusing a flow layout like this for more than 1 collection view:

UICollectionViewFlowLayout *flowLayout = [[UICollectionViewFlowLayout alloc] init]; [flowLayout setScrollDirection:UICollectionViewScrollDirectionHorizontal]; Collection1 = [[UICollectionView alloc] initWithFrame:CGRectMake(0.0f, 0.0f, 320.0f, 50.0f) collectionViewLayout:flowLayout]; [Collection1 setDataSource:self]; [Collection1 setDelegate:self]; [self.view addSubview:Collection1];  Collection2 = [[UICollectionView alloc] initWithFrame:CGRectMake(0.0f, 0.0f, 320.0f, self.view.frame.size.height) collectionViewLayout:flowLayout]; Collection2.backgroundColor = [UIColor whiteColor]; 

Instead if I create a new flow layout for each UICollectionView I avoid this crash. Hopefully that might help someone

UICollectionViewFlowLayout *flowLayout = [[UICollectionViewFlowLayout alloc] init]; [flowLayout setScrollDirection:UICollectionViewScrollDirectionHorizontal]; Collection1 = [[UICollectionView alloc] initWithFrame:CGRectMake(0.0f, 0.0f, 320.0f, 50.0f) collectionViewLayout:flowLayout]; [Collection1 setDataSource:self]; [Collection1 setDelegate:self]; [self.view Collection1];  UICollectionViewFlowLayout *flowLayoutVert = [[UICollectionViewFlowLayout alloc] init]; [flowLayoutVert setScrollDirection:UICollectionViewScrollDirectionVertical]; Collection2 = [[UICollectionView alloc] initWithFrame:CGRectMake(0.0f, 0.0f, 320.0f, self.view.frame.size.height) collectionViewLayout:flowLayoutVert];