如何为UIButton添加约束并使其以编程方式在执行操作后移动?

时间:2019-03-26 19:08:14

标签: swift uibutton xcode10.1

我在我的项目中使用了一些cocapods(DKCircleButton = OBJ-c中制造的UIButton),并且我试图添加约束并使用户点击后我的按钮移至底部。 我尝试了所有可能的解决方案,但没有一个起作用。

这是我的代码。

override func viewDidLoad() {
    super.viewDidLoad()

    let button = DKCircleButton(frame: CGRect(x: 0, y: 0, width: 150, height: 150))
    button.center = CGPoint(x: 160, y: 200)
    button.setTitle("Отмазаться", for: .normal)
    button.titleLabel?.font = UIFont.systemFont(ofSize: 20)
    button.addTarget(self, action: #selector(buttonPressed), for: .touchUpInside)
    button.animateTap = true
    button.backgroundColor = UIColor(red: 230/255, green: 103/255, blue: 103/255, alpha: 1.0)
    self.view.addSubview(button)

    let xPosition:CGFloat = 110
    let yPosition:CGFloat = 200
    let buttonWidth:CGFloat = 150
    let buttonHeight:CGFloat = 150

    button.frame = CGRect(x:xPosition, y:yPosition, width:buttonWidth, height:buttonHeight)

}

@objc func buttonPressed(sender: DKCircleButton) {
    // here's should be action associated with a tap, but it doesn't work at all
    // for example, I've tried to change the title of the bottom but this function doesn't recognise the "bottom" identifier
    print("got it")
}

1 个答案:

答案 0 :(得分:1)

主要问题实际上是一个非常普遍的问题:您尝试在定义变量的范围之外访问变量。您的let button是在viewDidLoad()内部定义的,因此只能从viewDidLoad()内部访问。为了能够更改其他函数中的内容,您可以进行更全局的引用,然后将其加载到viewDidLoad()中,如下所示:

var button : DKCircleButton!

override func viewDidLoad() {
    super.viewDidLoad()

    button = DKCircleButton(frame: CGRect(x: 0, y: 0, width: 150, height: 150))
    button.center = CGPoint(x: 160, y: 200)
    button.setTitle("Отмазаться", for: .normal)
    ....//no more changes here

}

@objc func buttonPressed(sender: DKCircleButton) {
    var newFrame = button.frame
    newFrame.width = 200 // You can change whatever property you want of course, this is just to give an example.
    button.frame = newFrame

    print("got it")
}

确保button变量在同一类内,但在任何其他函数之外。