对于Swift 2.2(带有新的“selector”声明)。

let btn = UIButton(type: UIButtonType.System) as UIButton
btn.frame = CGRectMake(0, 0, 100, 20) // set any frame you want
btn.setTitle("MyAction", forState: UIControlState.Normal)
btn.addTarget(self, action: #selector(MyClass.myAction(_:)), forControlEvents: UIControlEvents.TouchUpInside)
self.view.addSubview(btn)


func myAction(sender:UIButton!){
  // Some action 
}

对于Swift 3(更短的代码)

let button = UIButton(type: UIButtonType.custom)
button.frame = CGRect(x: 0, y: 0, width: 200.0, height: 40.0)
button.addTarget(nil, action: #selector(tapButton(_:)), for: UIControlEvents.touchUpInside)
button.tintColor = UIColor.white
button.backgroundColor = UIColor.red
button.setBackgroundImage(UIImage(named: "ImageName"), for: UIControlState.normal)
button.setTitle("MyTitle", for: UIControlState.normal)
button.isEnabled = true

func tapButton(sender: UIButton) {

}

要以编程方式在控制器视图中添加一个按钮，请使用以下命令:

-(void)viewDidLoad
{
   UIButton * btn = [UIButton buttonWithType:UIButtonTypeRoundedRect];
   btn.frame = CGRectMake(0, 0, 100, 50);
   [btn setTitle:@"Hello, world!" forState:UIControlStateNormal];
   [self.view addSubview:btn];
}

要加入其中三种，冲洗并重复。

UIButton *btnname = [UIButton buttonWithType:UIButtonTypeRoundedRect];

[btnname setTitle:@"Click Me" forState:UIControlStateNormal];

btnname.frame = CGRectMake(10, 10, 100, 140);

[self.view addSubview:btnname];

在Swift 5和Xcode 10.2中

基本上我们有两种类型的按钮。

1)系统类型按钮

2)自定义类型按钮(在自定义类型按钮中，我们可以为按钮设置背景图像)

而且这两种类型的按钮控制状态很少https://developer.apple.com/documentation/uikit/uicontrol/state

重要的州有

1)正常状态

2)选定状态

3)高亮状态

4)禁用状态……

//For system type button
let button = UIButton(type: .system)
button.frame = CGRect(x: 100, y: 250, width: 100, height: 50)
//  button.backgroundColor = .blue
button.setTitle("Button", for: .normal)
button.setTitleColor(.white, for: .normal)
button.titleLabel?.font = UIFont.boldSystemFont(ofSize: 13.0)
button.titleLabel?.textAlignment = .center//Text alighment center
button.titleLabel?.numberOfLines = 0//To display multiple lines in UIButton
button.titleLabel?.lineBreakMode = .byWordWrapping//By word wrapping
button.tag = 1//To assign tag value
button.btnProperties()//Call UIButton properties from extension function
button.addTarget(self, action:#selector(self.buttonClicked), for: .touchUpInside)
self.view.addSubview(button)

//For custom type button (add image to your button)
let button2 = UIButton(type: .custom)
button2.frame = CGRect(x: 100, y: 400, width: 100, height: 50)
//        button2.backgroundColor = .blue
button2.setImage(UIImage.init(named: "img.png"), for: .normal)
button2.tag = 2
button2.btnProperties()//Call UIButton properties from extension function
button2.addTarget(self, action:#selector(self.buttonClicked), for: .touchUpInside)
self.view.addSubview(button2)

@objc func buttonClicked(sender:UIButton) {
    print("Button \(sender.tag) clicked")
}

//You can add UIButton properties using extension
extension UIButton {
    func btnProperties() {
        layer.cornerRadius = 10//Set button corner radious
        clipsToBounds = true
        backgroundColor = .blue//Set background colour
        //titleLabel?.textAlignment = .center//add properties like this
    }
}

如果愿意，可以将创建者实例放入循环中，并从数组中动态添加名称。