In Swift, how do you detect which UIControlEvents triggered the action?

Question

I currently have 4 UITextField's

@IBOutlet weak var fNameTextField: UITextField!
@IBOutlet weak var lNameTextField: UITextField!
@IBOutlet weak var emailTextField: UITextField!
@IBOutlet weak var phoneTextField: UITextField!

and I want to keep track of their various events:

[UIControlEvents.EditingChanged, UIControlEvents.EditingDidBegin, UIControlEvents.EditingDidEnd ]

but I don't want to have 3 event separate event handlers so I created a single function like this. This function does a great job of telling me which UITextField fired an event but it doesn't tell me which event was triggered.:

fNameTextField.addTarget(self, action: "onChangeTextField:", forControlEvents: UIControlEvents.AllTouchEvents)
lNameTextField.addTarget(self, action: "onChangeTextField:", forControlEvents: UIControlEvents.AllTouchEvents)
emailTextField.addTarget(self, action: "onChangeTextField:", forControlEvents: UIControlEvents.AllTouchEvents)
phoneTextField.addTarget(self, action: "onChangeTextField:", forControlEvents: UIControlEvents.AllTouchEvents)

func onChangeTextField(sender:UITextField){
    switch(sender){
        case fNameTextField:
            print("First Name")
        case lNameTextField:
            print("Last Name")
        case emailTextField:
            print("E-mail")
        case phoneTextField:
            print("Phone")
        default: break
    }
}

How can I print both the name of the sender and the name of the event triggered (ex: .EditingDidEnd, .EditingDidEnd, .EditingDidEnd)?

Ideally, I do not want to write multiple event handlers, I'd prefer a single function.

Something like this:

func onChangeTextField(sender:UITextField){
    switch(sender.eventTriggerd){
        case UIControlEvents.EditingChanged:
            println("EditingChanged")
        case UIControlEvents.EditingDidBegin:
            println("EditingDidBegin")
        case UIControlEvents.EditingDidEnd:
            println("EditingDidEnd")
        default: break
    }
}

Answer 1

Unfortunately, you cannot distinguish what control event triggered an action handler. This has nothing to do with Swift; it's just a feature of Cocoa.

It's a strange design decision, but that's just how it is. See, for example, my book, which complains about it:

Curiously, none of the action selector parameters provide any way to learn which control event triggered the current action selector call! Thus, for example, to distinguish a Touch Up Inside control event from a Touch Up Outside control event, their corresponding target–action pairs must specify two different action handlers; if you dispatch them to the same action handler, that handler cannot discover which control event occurred.