Attach parameter to button addTarget action in Swift

Question

I am trying to pass an extra parameter to the buttonClicked action  but cannot work out what the syntax should be in Swift   button addTarget self  action   buttonClicked    forControlEvents  UIControlEvents TouchUpInside    Any my buttonClicked method   func buttonClicked sender UIButton        println  hello       Anyone any ideas   Thanks for your help

User · Answer

If you have a loop of buttons like me you can try something like this  var buttonTags  Int String      can be  Int Any  let myArray    0  a  1  b   for  index value  in myArray         let button      Create a button       buttonTags  index    myArray index       button tag   index      button addTarget self  action   selector buttonAction       for   touchDown      objc func buttonAction   sender UIButton         let myString   buttonTags sender tag

User · Answer

I appreciate everyone saying use tags  but really you need to extend the UIButton class and simply add the object there     Tags are a hopeless way round this  Extend the UIButton like this  in Swift 4   import UIKit class PassableUIButton  UIButton      var params  Dictionary lt String  Any gt      override init frame  CGRect            self params               super init frame  frame             required init  coder aDecoder  NSCoder            self params               super init coder  aDecoder            then your call may be call  NOTE THE colon     in Selector   webButtonTouched       let webButton   PassableUIButton frame  CGRect x 310  y 40  width 40  height 40   webButton setTitle  Visit  for   normal  webButton addTarget self  action   selector YourViewController webButtonTouched       for  touchUpInside  webButton params  myvalue      bob    then finally catch it all here   IBAction func webButtonTouched   sender  PassableUIButton        print sender params  myvalue              You do this one time and use it throughout your project  you can even make the child class have a generic  object  and put whatever you like into the button    Or use the example above to put an inexhaustible number of key string params into the button   Really useful for including things like urls  confirm message methodology etc  As an aside  it s important that the SO community realise this there is an entire generation of bad practice being cut n paste round the internet by an alarming number of programmers who don t understand haven t been taught missed the point of the concept of object extensions

User · Answer

Swift 4 2  Result   testButton on  touchUpInside     sender  event  in        You can use any reference initialized before the code block here        You can access self by adding  weak self  before  sender  event         You can then either make self strong by using a guard statement or use a optional operator         print  user did press test button       In the file UIButton Events swift I ve created an extension method for UIButton that binds a UIControl Event to a completion handler called EventHandler   import UIKit  fileprivate var bindedEvents   UIButton EventBinder         fileprivate class EventBinder        let event  UIControl Event     let button  UIButton     let handler  UIButton EventHandler     let selector  Selector      required init            event  UIControl Event          on button  UIButton          withHandler handler   escaping UIButton EventHandler                 self event   event         self button   button         self handler   handler         self selector    selector performEvent on ofType            button addTarget self  action  self selector  for  event             deinit           button removeTarget self  action  selector  for  event          if let index   bindedEvents index forKey  button                bindedEvents remove at  index                     private extension EventBinder         objc func performEvent on sender  UIButton  ofType event  UIControl Event            handler sender  event           extension UIButton        typealias EventHandler    UIButton  UIControl Event  - gt  Void      func on   event  UIControl Event  handler   escaping EventHandler            bindedEvents self    EventBinder event  on  self  withHandler  handler            The reason why I used a custom class for binding the event is to be able to dispose the reference later when the button is deintialised  This will prevent a possible memory leak from occurring  This wasn t possible within the UIButton its extension  because I m not allowed to implement a property nor the deinit method

User · Answer

This is more of an important comment  Sharing references of sytanx that is acceptable out of the box  For hack solutions look at other answers    Per Apple s docs  Action Method Definitions have to be either one of these three  Anything else is unaccepted     IBAction func doSomething    IBAction func doSomething sender  UIButton   IBAction func doSomething sender  UIButton  forEvent event  UIEvent

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Swift 5 0 code  I use theButton tag but if i have plenty type of option  its be very long switch case    theButton addTarget self  action   selector theFunc   for   touchUpInside   theButton frame name    myParameter        objc func theFunc sender UIButton    print sender frame name

User · Answer

For Swift 2 X and above  button addTarget self action  selector YourControllerName buttonClicked                                forControlEvents  TouchUpInside

User · Answer

Swift 4 0 code  Here we go again   The called action should marked like this because that is the syntax for swift function for exporting functions into objective c language    objc func deleteAction sender  UIButton        create some working button   let deleteButton   UIButton type   roundedRect  deleteButton setTitle  Delete   for      deleteButton addTarget self  action   selector   MyController deleteAction sender     for   touchUpInside

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Swift 3 0 code  self timer   Timer scheduledTimer timeInterval  timeInterval  target  self  selector  selector fetchAutocompletePlaces timer     userInfo  textView text   repeats  true   func fetchAutocompletePlaces timer   Timer       let keyword   timer userInfo     You can send value in  userinfo  and use that as parameter in the function

User · Answer

If you want to send additional parameters to the buttonClicked method  for example an indexPath or urlString  you can subclass the UIButton   class SubclassedUIButton  UIButton       var indexPath  Int      var urlString  String      Make sure to change the button s class in the identity inspector to subclassedUIButton   You can access the parameters inside the buttonClicked method using sender indexPath or sender urlString   Note  If your button is inside a cell you can set the value of these additional parameters in the cellForRowAtIndexPath method  where the button is created

User · Answer

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

User · Answer

For Swift 3 0 you can use following  button addTarget self  action   selector YourViewController YourMethodName       for  touchUpInside   func YourMethodName   sender   UIButton        print sender tag

[swift] Attach parameter to button.addTarget action in Swift

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