How to unwrap the optional value

Question

I have a method like this:

internal func handlePan(_ sender: UIPanGestureRecognizer) {
    if (sender.state == .began) {
        let initialPanPoint = sender.location(in: collectionView)
        findDraggingCellByCoordinate(initialPanPoint)
    } else if (sender.state == .changed) {
        let newCenter = sender.translation(in: collectionView!)
        updateCenterPositionOfDraggingCell(newCenter)
    } else {
        if let indexPath = draggedCellPath {
           // finishedDragging(collectionView!.cellForItem(at: indexPath)!)
            finishedDragging((collectionView?.cellForItem(at: indexPath))!)
        }
    }
}

And I am getting a crash on

finishedDragging((collectionView?.cellForItem(at: indexPath))!)

fatal error: unexpectedly found nil while unwrapping an Optional value

How can I unwrap this? Please help me. Thanks.

Duplicate of every other "unexpectedly found nil" question (and there are thousands of them). `!` means crash. — matt, Jul 30 '17 at 18:06

Josh Hamet · Accepted Answer · 2017-07-30T18:03:51.983

Currently, you're force unwrapping an optional which happens to be nil. Therefore, you need to add an additional clause to thee optional unwrapping of indexPath to determine if the collection view can return a cell at that index path. If the collection view cannot return a cell at index path, it will return nil and the condition will not be executed.

if let indexPath = draggedCellPath, let cell = collectionView?.cellForItem(at: indexPath){
  finishedDragging(cell)
}

How to unwrap the optional value

1 Answers1