unrecognized selector sent to instance 0x8c9a6d0

Question

Can anyone tell me what is going on in this error code

[UIViewController collectionView:numberOfItemsInSection:]: unrecognized selector sent to instance 0x8c         


        

Answer 1

also it could be you have forgotten delegate methods after class name

class YourClassName: UIViewController, UICollectionViewDataSource, UICollectionViewDelegate, UICollectionViewDelegateFlowLayout{
}