Adding gestures to your dateCells

Gestures are actually added on your calendar instance instead of your cells.

Paste the following code in your project. This code adds double taps

override func viewDidLoad() {
    let doubleTapGesture: UITapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(didDoubleTapCollectionView(gesture:)))
    doubleTapGesture.numberOfTapsRequired = 2  // add double tap
    calendarView.addGestureRecognizer(doubleTapGesture)
}

func didDoubleTapCollectionView(gesture: UITapGestureRecognizer) {
    let point = gesture.location(in: gesture.view!)
    let cellState = calendarView.cellStatus(at: point)
    print(cellState!.date)
}

Complete!