How to use addTarget method in swift 3

Question

here is my button object

    let loginRegisterButton:UIButton = {
    let button = UIButton(type: .system)
    button.backgroundColor = UIColor(r: 50 , g: 80, b: 130)
    button.setTitle("Register", for: .normal)
    button.translatesAutoresizingMaskIntoConstraints = false
    button.setTitleColor(.white, for: .normal)
    button.addTarget(self, action:#selector(handleRegister), for: .touchUpInside)
    return button
}()

and here is my function

    func handleRegister(){

    FIRAuth.auth()?.createUser(withEmail: email, password: password,completion: { (user, error) in

        if error != nil
        { print("Error Occured")}

        else
        {print("Successfully Authenticated")}
    })        
}

I'm getting compile error, if addTarget removed it compiles successfully

Solution 1

Yes, don't add "()" if there is no param

button.addTarget(self, action:#selector(handleRegister), for: .touchUpInside). 

and if you want to get the sender

button.addTarget(self, action:#selector(handleRegister(_:)), for: .touchUpInside). 

func handleRegister(sender: UIButton){
   //...
}

Edit:

button.addTarget(self, action:#selector(handleRegister(_:)), for: .touchUpInside)

no longer works, you need to replace _ in the selector with a variable name you used in the function header, in this case it would be sender, so the working code becomes:

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

Solution 2

Try this with Swift 4

buttonSection.addTarget(self, action: #selector(actionWithParam(_:)), for: .touchUpInside)
@objc func actionWithParam(sender: UIButton){
    //...
}

buttonSection.addTarget(self, action: #selector(actionWithoutParam), for: .touchUpInside)
@objc func actionWithoutParam(){
    //...
}

Solution 3

Try this

button.addTarget(self, action:#selector(handleRegister()), for: .touchUpInside). 

Just add parenthesis with name of method.

Also you can refer link : Value of type 'CustomButton' has no member 'touchDown'

Solution 4

  let button: UIButton = UIButton()
    button.setImage(UIImage(named:"imagename"), for: .normal)
    button.addTarget(self, action:#selector(YourClassName.backAction(_sender:)), for: .touchUpInside)

    button.frame = CGRect.init(x: 5, y: 100, width: 45, height: 45)
    view.addSubview(button)

    @objc public func backAction(_sender: UIButton) {

    }

Solution 5

Try with swift 3

cell.TaxToolTips.tag = indexPath.row
        cell.TaxToolTips.addTarget(self, action: #selector(InheritanceTaxViewController.displayToolTipDetails(_:)), for:.touchUpInside)


 @objc func displayToolTipDetails(_ sender : UIButton) {
        print(sender.tag)
        let tooltipString = TaxToolTipsArray[sender.tag]
        self.displayMyAlertMessage(userMessage: tooltipString, status: 202)    
}

View more solutions

Comments

[Iulian Onofrei]

Actually, don't add any parantheses

[marlonpya]

ok that is really easy.. but how add a value example.. button.addTarget(self, action:#selector(handleRegister(str: "Hello")), for: .touchUpInside) ?

[Damien Romito]

You cannot set parameter in a selector . The action depends on the origin of the target. If you want get the string of the button, get it from the sender in handleRegister(sender: UIButton) let string = sender. currentTitle

[Kushal Ashok]

One of the workarounds is to set the parameter as the button's accessibility element. But not sure if this is accepted by App Store since I only tried for Enterprise apps.

[Aron]

Not a huge issue, but is there still no way to do this without exposing to @objc?

[Soumen]

As Apple Official Documentation (developer.apple.com/documentation/swift/…), you need to use @objc to call your Selector Method, no other "pure swift" way of using the selector.