Detect UILabel text change in swift

Question

Is there a way to get notified when there is a change in a UILabel\'s text or would I be better off using a UITextField with userInteractionE

Answer 1

For Swift 3.2 and later, the preferred method is to use a closure-based observer:

@IBOutlet public weak var label: UILabel!

var textObserver: NSKeyValueObservation?

func someAppropriateFunction() {
  ...
  textObserver = label.observe(\.text) { [weak self] (label, observedChange) in
    self?.updateStuff()
  }
}

The closure will pass you the label instance and an NSKeyValueObservedChange that includes the following properties:

  indexes: IndexSet?
  isPrior: Bool
  kind: NSKeyValueObservedChange.Kind
  newValue: Value?
  oldValue: Value?