我如何以编程方式创建图形元素(如UIButton)在Swift?我试图创建和添加按钮到一个视图,但不能。


当前回答

这是可能的。除了使用swift语法之外,您几乎可以以相同的方式完成所有操作。例如,你可以用这样的代码创建一个UIButton:

 var button: UIButton = UIButton(frame: CGRectMake(0, 0, 100, 100))

其他回答

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")
}

API没有改变——只有语法改变了。你可以创建一个UIButton并像这样添加它:

var button = UIButton(frame: CGRectMake(0, 0, 50, 50))
self.view.addSubview(button) // assuming you're in a view controller
            let myFirstButton = UIButton()
            myFirstButton.setTitle("Software Button", forState: .Normal)
            myFirstButton.setTitleColor(UIColor.redColor(), forState: .Normal)
            myFirstButton.frame = CGRectMake(100, 300, 150, 50)
            myFirstButton.backgroundColor = UIColor.purpleColor()
            myFirstButton.layer.cornerRadius = 14
            myFirstButton.addTarget(self, action: "pressed:", forControlEvents: .TouchUpInside)
            self.view.addSubview(myFirstButton)
            myFirstButton.hidden=true
            nameText.delegate = self


func pressed(sender: UIButton!) {
        var alertView = UIAlertView()
        alertView.addButtonWithTitle("Ok")
        alertView.title = "title"
        alertView.message = "message"
        alertView.show();
    }

从storyboard创建UIButton: 1 -将UIButton对象从对象库拖到storyboard文件中的ViewController 2 -节目助理编辑 3 -从上面创建的UIButton中右键拖动到你的类中。结果如下:

@IBAction func buttonActionFromStoryboard(sender: UIButton)
{
    println("Button Action From Storyboard")
}

为创建UIButton编程: 1-写入“override func viewDidLoad()”:

        let uiButton    = UIButton.buttonWithType(UIButtonType.System) as UIButton
        uiButton.frame  = CGRectMake(16, 116, 288, 30)
        uiButton.setTitle("Second", forState: UIControlState.Normal);
        uiButton.addTarget(self, action: "buttonActionFromCode:", forControlEvents: UIControlEvents.TouchUpInside)
        self.view.addSubview(uiButton)

2-添加IBAction功能:

@IBAction func buttonActionFromCode(sender:UIButton)
{
    println("Button Action From Code")
}

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。