UICollectionView must be initialized with a non-nil layout parameter

Question

I'm new to `UICollectionView` and I'm following a tutorial I found on the web but I'm stuck on an error I can't figure out. Here's a bit of context. In the debugger I can see that following is happening: - `numberOfSectionsInCollectionView`: is called and I return 1 - `collectionView:numberOfItemsInSection:` is called and I return the size of the model (20) - `collectionView:layout:sizeForItemAtIndexPath:` gets called once for each item in the model - `collectionView:layout:insetForSectionAtIndex:` is called `collectionView:cellForItemAtIndexPath:` gets called and it crashes on this line... ``` UICollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:@"MyCell" forIndexPath:indexPath]; ``` with this error... ``` *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'UICollectionView must be initialized with a non-nil layout parameter' ``` When I pause execution on that line and check the console it appears that there is a layout.…

Accepted Answer

As it turns out the problem was with `registerClass:`. I had this:

```
[self.collectionView registerClass:[UICollectionView class] 
        forCellWithReuseIdentifier:@"MyCell"];
```

but it should have been this:

```
[self.collectionView registerClass:[UICollectionViewCell class] 
        forCellWithReuseIdentifier:@"MyCell"];
```

So the dequeue method was creating a `UICollectionView` instead of a `UICollectionViewCell`.

UICollectionView must be initialized with a non-nil layout parameter

Solution

Problem