How can I check if an indexPath is valid, thus avoiding an "attempt to scroll to invalid index path" error?

Question

How can I check to see whether an indexPath is valid or not?

I want to scroll to an indexPath, but I sometimes get an error if my UICollectionView subviews aren't finished loading.

Answer 1

You could check

- numberOfSections - numberOfItemsInSection:  

of your UICollection​View​Data​Source to see if your indexPath is a valid one.

E.g.

extension UICollectionView {      func isValid(indexPath: IndexPath) -> Bool {         guard indexPath.section < numberOfSections,               indexPath.row < numberOfItems(inSection: indexPath.section)             else { return false }         return true     }  } 

Answer 2

A more concise solution?

func indexPathIsValid(indexPath: NSIndexPath) -> Bool {     if indexPath.section >= numberOfSectionsInCollectionView(collectionView) {         return false     }     if indexPath.row >= collectionView.numberOfItemsInSection(indexPath.section) {         return false     }     return true } 

or more compact, but less readable...

func indexPathIsValid(indexPath: NSIndexPath) -> Bool {     return indexPath.section < numberOfSectionsInCollectionView(collectionView) && indexPath.row < collectionView.numberOfItemsInSection(indexPath.section) }