How to Use Addtarget Method in Swift 3

Attach parameter to button.addTarget action in Swift

You cannot pass custom parameters in addTarget:.One alternative is set the tag property of button and do work based on the tag.

button.tag = 5
button.addTarget(self, action: "buttonClicked:", 
    forControlEvents: UIControlEvents.TouchUpInside)

Or for Swift 2.2 and greater:

button.tag = 5
button.addTarget(self,action:#selector(buttonClicked),
    forControlEvents:.TouchUpInside)

Now do logic based on tag property

@objc func buttonClicked(sender:UIButton)
{
    if(sender.tag == 5){

        var abc = "argOne" //Do something for tag 5
    }
    print("hello")
}

Add target to Button in Swift

Matt is right!! your approach is totally wrong here. Please try to modify your approach.

Your approach should be something like this:

override func viewDidLoad() {
    super.viewDidLoad()

    //Set Target to your button only once.
    editButton.addTarget(self, action: #selector(didTapEditButton), for: .touchUpInside)

}

@objc func didTapEditButton() {

    //Add IF conditions according to what your button should do in different cases here. 
    if user.uid == UserApi.shared.CURRENT_USER_ID {
        goToSettings()
    }else {
        if user.isFollowing! == true {
            setupUnfollowButton()
        } else {
            setupFollowButton()
        }
    }

}


func setupFollowButton() {

    //Make the check to see what state your button is currently in by checking if the title of the button is "Follow" or "Unfollow"
    if editButton.titleLabel?.text == "Unfollow"{
        editButton.layer.borderWidth = 1
        editButton.layer.borderColor = UIColor.lightGray.cgColor
        editButton.layer.cornerRadius = 5
        editButton.clipsToBounds = true

        editButton.setTitleColor(UIColor.white, for: .normal)
        editButton.backgroundColor = UIColor(red: 1 / 255, green: 84 / 255, blue: 147 / 255, alpha: 1.0)
        editButton.setTitle("Follow", for: UIControl.State.normal)

        followAction()
    }
}


 func setupUnfollowButton() {

    //Do the same here for the other state.
    if editButton.titleLabel?.text == "Follow"{
        editButton.layer.borderWidth = 1
        editButton.layer.borderColor = UIColor.lightGray.cgColor
        editButton.layer.cornerRadius = 5
        editButton.clipsToBounds = true

        editButton.setTitleColor(UIColor.black, for: .normal)
        editButton.backgroundColor = UIColor.white
        editButton.setTitle("Unfollow", for: UIControl.State.normal)

        unFollowAction()
    }
}


func followAction() {
    print("Button wurde gedrückt")
    if user?.isFollowing == false {
        FollowApi.shared.followAction(withUser: user!.uid!)
        setupUnfollowButton()
        user?.isFollowing = true

    }
}

func unFollowAction() {
    print("Button wurde gedrückt")
    if user?.isFollowing == true {
        FollowApi.shared.unfollowAction(withUser: user!.uid!)
        setupFollowButton()
        user?.isFollowing = false
    }
}

UIButton.addTarget with swift 3 and local function

Here you need to use objc_setAssociatedObject

Add extension in project:-

extension UIButton {
private struct AssociatedKeys {
    static var DescriptiveName = "KeyValue"
}

@IBInspectable var descriptiveName: String? {
    get {
        return objc_getAssociatedObject(self, &AssociatedKeys.DescriptiveName) as? String
    }
    set {
        if let newValue = newValue {
            objc_setAssociatedObject(
                self,
                &AssociatedKeys.DescriptiveName,
                newValue as NSString?,
                objc_AssociationPolicy.OBJC_ASSOCIATION_RETAIN
            )
        }
    }
}
}

How to use :-

//let newI = i.replacingOccurrences(of: "GPS30", with: "")
button?.descriptiveName = "stringData" //newI use here

How to get parameter :-

func buttonAction(sender: UIButton!) {
            print(sender.descriptiveName)
}

UIControl addTarget(_:action:for:) Method in Swift 3.2

Yes, they changed it from a String where it was simply a runtime error if you mistyped a method name to a #selector that forces a compile time check for the method. They're just trying to find your errors earlier.

However, if awesomeMethod is NOT in ClassA, let's say it's in ClassB,
then the compiler complains and I am forced to specify the class name
in the action.

No, you can specify an @objc protocol that implements the method:

@objc protocol AwesomeProtocol {
    func awesomeMethod()
}

Then, even if your class doesn't implement that method, you can specify:

awesomeBtn.addTarget(nil, action: #selector(AwesomeProtocol.awesomeMethod), for: .touchUpInside)

Note: It doesn't seem to be necessary for anyone to adopt that protocol. The button searches up the responder chain and uses the first matching method that it finds. Although, you should adopt the protocol by any class that implements awesomeMethod so that Swift can detect errors in the method signature at compile time.

Swift 3 UIButton addTarget not working

It works fine when i try your code with one change as i don't have backView. So replaced

backView.addSubview(backButton)

with

 self.view.addSubview(backButton)

I can see the log present in pressBackButton function on console on pressing the button. Make sure your console view is not disabled. shift+command+C shows the console view.

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