UICollectionViewController使用，pushViewController彈出時

UICollectionViewController不同于其他viewcontroller，在使用過程中特别容易出現這種錯誤

UICollectionView must be initialized with a non-nil layout parameter

如果是這樣（已經建立了一個UICollectionViewController的storyboard），這是因為你還沒有關聯上storyboard。

以下是國外一個論壇上面的解釋：

So you need to pass it a layout object. You don't show the code where you make a collection view, but I'm assuming 

CollectionViewController

 is a 

UICollectionViewController

subclass, in which case you need to use this designated initialiser:

Currently, you're using 

init

.

In both cases you need to create and pass in a layout object when initalising.

If your collection view is held in the storyboard then you need to get it from the storyboard using 

instantiateViewControllerWithIdentifier:

, so your code above would read something like:

viewController = [self.storyboard instantiateViewControllerWithIdentifier:@"CollectionViewController"];


           

另外在使用UICollectionViewCell的時候自動會生成

static NSString * const reuseIdentifier = @"Cell";這個變量注冊時候無需更改，隻在要使用的時候使用自定義辨別即可。