UICollectionViewController使用，pushViewController弹出时

UICollectionViewController不同于其他viewcontroller，在使用过程中特别容易出现这种错误

UICollectionView must be initialized with a non-nil layout parameter

如果是这样（已经建立了一个UICollectionViewController的storyboard），这是因为你还没有关联上storyboard。

以下是国外一个论坛上面的解释：

- (id)initWithFrame:(CGRect)frame collectionViewLayout:(UICollectionViewLayout *)layout

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:

- (id)initWithCollectionViewLayout:(UICollectionViewLayout *)layout

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的时候自动会生成
static NSString *
const reuseIdentifier = @"Cell";这个变量注册时候无需更改，只在要使用的时候使用自定义标识即可。