如何以编程方式创建 UIButton

Question

我正在尝试构建UIViews 以编程方式。如何在 Swift 中获得带有动作函数的UIButton？

以下代码没有任何动作：

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

下面的选择器函数是：

func buttonAction(sender: UIButton!) {
    var btnsendtag: UIButton = sender
}

Answer 1

您只是错过了UIButton 这是哪个。为了弥补这一点，请更改其 tag 属性。
这是你的答案：

let btn: UIButton = UIButton(frame: CGRectMake(100, 400, 100, 50))
btn.backgroundColor = UIColor.greenColor()
btn.setTitle("Click Me", forState: UIControlState.Normal)
btn.addTarget(self, action: "buttonAction:", forControlEvents: UIControlEvents.TouchUpInside)
btn.tag = 1               // change tag property
self.view.addSubview(btn) // add to view as subview

Swift 3.0

let btn: UIButton = UIButton(frame: CGRect(x: 100, y: 400, width: 100, height: 50))
btn.backgroundColor = UIColor.green
btn.setTitle(title: "Click Me", for: .normal)
btn.addTarget(self, action: #selector(buttonAction), forControlEvents: .touchUpInside)
btn.tag = 1               
self.view.addSubview(btn)

这里是一个示例选择器函数：

func buttonAction(sender: UIButton!) {
    var btnsendtag: UIButton = sender
    if btnsendtag.tag == 1 {            
        //do anything here
    }
}

Answer 2

使用标签是一个脆弱的解决方案。您有一个视图，并且您正在创建按钮并将其添加到该视图，您只需要保留对它的引用：例如

在您的班级中，保留对按钮的引用

var customButton: UIButton!

创建按钮并设置参考

let btn = UIButton(frame: CGRect(x: 100, y: 400, width: 100, height: 50))
btn.backgroundColor = .greenColor()
btn.setTitle("Click Me", forState: .Normal)
btn.addTarget(self, action: #selector(MyClass.buttonAction), forControlEvents: .TouchUpInside)
self.view.addSubview(btn)
customButton = btn

在动作函数中针对此实例进行测试

func buttonAction(sender: UIButton!) {
    guard sender == customButton else { return }

    // Do anything you actually want to do here
}

Answer 3

你必须在那个btn上addSubview和tag。