@selector() in Swift?

Question

I\'m trying to create an NSTimer in Swift but I\'m having some trouble.

NSTimer(timeInterval: 1, target: self, selector: test(), us         


        

Answer 1

For swift 3

let timer = Timer.scheduledTimer(timeInterval: 0.01, target: self, selector: #selector(self.test), userInfo: nil, repeats: true)

Function declaration In same class:

@objc func test()
{
    // my function
} 

Answer 2

For Swift 3

//Sample code to create timer

Timer.scheduledTimer(timeInterval: 1, target: self, selector: (#selector(updateTimer)), userInfo: nil, repeats: true)

WHERE
timeInterval:- Interval in which timer should fire like 1s, 10s, 100s etc. [Its value is in secs]
target:- function which pointed to class. So here I am pointing to current class.
selector:- function that will execute when timer fires.

func updateTimer(){
    //Implemetation 
} 

repeats:- true/false specifies that timer should call again n again.

Answer 3

Change as a simple string naming in the method calling for selector syntax

var timer1 : NSTimer? = nil
timer1= NSTimer(timeInterval: 0.1, target: self, selector: Selector("test"), userInfo: nil, repeats: true)

After that, type func test().

Answer 4

I found many of these answers to be helpful but it wasn't clear how to do this with something that wasn't a button. I was adding a gesture recognizer to a UILabel in swift and struggled so here's what I found worked for me after reading everything above:

let tapRecognizer = UITapGestureRecognizer(
            target: self,
            action: "labelTapped:")

Where the "Selector" was declared as:

func labelTapped(sender: UILabel) { }

Note that it is public and that I am not using the Selector() syntax but it is possible to do this as well.

let tapRecognizer = UITapGestureRecognizer(
            target: self,
            action: Selector("labelTapped:"))

Answer 5

Selector in Swift 4:

button.addTarget(self, action: #selector(buttonTapped(sender:)), for: UIControlEvents.touchUpInside)

Answer 6

It may be useful to note where you setup the control that triggers the action matters.

For example, I have found that when setting up a UIBarButtonItem, I had to create the button within viewDidLoad or else I would get an unrecognized selector exception.

override func viewDidLoad() {
    super.viewDidLoad() 

    // add button
    let addButton = UIBarButtonItem(image: UIImage(named: "746-plus-circle.png"), style: UIBarButtonItemStyle.Plain, target: self, action: Selector("addAction:"))
    self.navigationItem.rightBarButtonItem = addButton
}

func addAction(send: AnyObject?) {     
    NSLog("addAction")
}