你可以这样创建，也可以这样添加动作....

import UIKit

let myButton = UIButton(frame: CGRect(x: 0, y: 0, width: 50, height: 50))

init(nibName nibNameOrNil: String!, bundle nibBundleOrNil: NSBundle!)
{       super.init(nibName: nibName, bundle: nibBundle) 
        myButton.targetForAction("tappedButton:", withSender: self)
}

func tappedButton(sender: UIButton!)
{ 
     println("tapped button")
}

下面是一个完整的解决方案，以编程方式添加一个UIButton与targetAction。 斯威夫特2.2

override func viewDidLoad() {
  super.viewDidLoad()

  let button = UIButton(frame: CGRect(x: 100, y: 100, width: 100, height: 50))
  button.backgroundColor = .greenColor()
  button.setTitle("Test Button", forState: .Normal)
  button.addTarget(self, action: #selector(buttonAction), forControlEvents: .TouchUpInside)

  self.view.addSubview(button)
}

func buttonAction(sender: UIButton!) {
  print("Button tapped")
}

使用NSLayoutConstraint而不是frame来正确地为每个iPhone屏幕放置按钮可能更好。

Swift 3.1的更新代码:

override func viewDidLoad() {
  super.viewDidLoad()

  let button = UIButton(frame: CGRect(x: 100, y: 100, width: 100, height: 50))
  button.backgroundColor = .green
  button.setTitle("Test Button", for: .normal)
  button.addTarget(self, action: #selector(buttonAction), for: .touchUpInside)

  self.view.addSubview(button)
}

func buttonAction(sender: UIButton!) {
  print("Button tapped")
}

Swift 4.2的更新代码:

override func viewDidLoad() {
  super.viewDidLoad()

  let button = UIButton(frame: CGRect(x: 100, y: 100, width: 100, height: 50))
  button.backgroundColor = .green
  button.setTitle("Test Button", for: .normal)
  button.addTarget(self, action: #selector(buttonAction), for: .touchUpInside)

  self.view.addSubview(button)
}

@objc func buttonAction(sender: UIButton!) {
  print("Button tapped")
}

如果func buttonAction声明为private或internal，上述方法仍然有效。

Swift 5和Swift 4一样

 let button = UIButton()
 button.frame = CGRect(x: self.view.frame.size.width - 60, y: 60, width: 50, height: 50)
 button.backgroundColor = UIColor.red
 button.setTitle("Name your Button ", for: .normal)
 button.addTarget(self, action: #selector(buttonAction), for: .touchUpInside)
 self.view.addSubview(button)

 @objc func buttonAction(sender: UIButton!) {
    print("Button tapped")
 }

Uilabel code 

var label: UILabel = UILabel()
label.frame = CGRectMake(50, 50, 200, 21)
label.backgroundColor = UIColor.blackColor()
label.textColor = UIColor.whiteColor()
label.textAlignment = NSTextAlignment.Center
label.text = "test label"
self.view.addSubview(label)

是的，在模拟器里。有时它不会识别选择器，这似乎是一个错误。即使我面对的不是你的代码，然后我只是改变了动作名称(选择器)。它的工作原理

let buttonPuzzle:UIButton = UIButton(frame: CGRectMake(100, 400, 100, 50))
buttonPuzzle.backgroundColor = UIColor.greenColor()
buttonPuzzle.setTitle("Puzzle", forState: UIControlState.Normal)
buttonPuzzle.addTarget(self, action: "buttonAction:", forControlEvents: UIControlEvents.TouchUpInside)
buttonPuzzle.tag = 22;
self.view.addSubview(buttonPuzzle)

选择器函数在这里:

func buttonAction(sender:UIButton!)
{

    var btnsendtag:UIButton = sender
    if btnsendtag.tag == 22 {            
        //println("Button tapped tag 22")
    }
}

这对我来说非常好，#DynamicButtonEvent #IOS #Swift #Xcode

func setupButtonMap(){
    let mapButton = UIButton(type: .system)
    mapButton.setImage(#imageLiteral(resourceName: "CreateTrip").withRenderingMode(.alwaysOriginal), for: .normal)
    mapButton.frame = CGRect(x: 0, y: 0, width: 34, height: 34)
    mapButton.contentMode = .scaleAspectFit
    mapButton.backgroundColor = UIColor.clear
    mapButton.addTarget(self, action: #selector(ViewController.btnOpenMap(_:)), for: .touchUpInside)
    navigationItem.leftBarButtonItem = UIBarButtonItem(customView: mapButton)
    }
@IBAction func btnOpenMap(_ sender: Any?) {
    print("Successful")
}