Passing arguments to selector in Swift

Question

I\'m programmatically adding a UITapGestureRecognizer to one of my views:

let gesture = UITapGestureRecognizer(target: self, action: #selector(self.handleTap         


        

Answer 1

Swift 5.0 iOS 13

I concur a great answer by Ninad. Here is my 2 cents, the same and yet different technique; a minimal version.

Create a custom class, throw a enum to keep/make the code as maintainable as possible.

enum Vs: String {
  case pulse = "pulse"
  case precision = "precision"
} 

class customTap: UITapGestureRecognizer {
  var cutomTag: String?
}

Use it, making sure you set the custom variable into the bargin. Using a simple label here, note the last line, important labels are not normally interactive.

let precisionTap = customTap(target: self, action: #selector(VC.actionB(sender:)))
precisionTap.customTag = Vs.precision.rawValue
precisionLabel.addGestureRecognizer(precisionTap)
precisionLabel.isUserInteractionEnabled = true

And setup the action using it, note I wanted to use the pure enum, but it isn't supported by Objective C, so we go with a basic type, String in this case.

@objc func actionB(sender: Any) {
// important to cast your sender to your cuatom class so you can extract your special setting.
  let tag = customTag as? customTap
  switch tag?.sender {
    case Vs.pulse.rawValue:
      // code
    case Vs.precision.rawValue:
      // code
    default:
      break
    }
}

And there you have it.