iOS9 UIButton初始化

Question

我正在尝试以编程方式初始化 UIButton，但看到以下错误之一：

buttonWithType is unavailable: use object construction UIButton(type:)

或

error: incorrect argument label in call (have 'buttonWithType:', expected 'type:')

  for char in keys {
        let btn: UIButton = UIButton.buttonWithType(UIButtonType.System) as UIButton

        btn.frame = CGRectMake(0, 0, 20, 20)
        btn.setTitle(char, forState: .Normal)
        btn.sizeToFit()
        btn.titleLabel?.font = UIFont.systemFontOfSize(20)

        btn.backgroundColor = UIColor(hue: (216/360.0), saturation: 0.1, brightness: 0.81, alpha: 1)//
        btn.setTitleColor(UIColor(white: 1.0, alpha: 1.0), forState: .Normal)

        btn.setContentHuggingPriority(1000, forAxis: .Horizontal)
        btn.setContentCompressionResistancePriority(1000, forAxis: .Horizontal)

        btn.addTarget(self, action: Selector("handleBtnPress:"), forControlEvents: .TouchUpInside)

        self.addSubview(btn)
    }

Answer 1

UIButton 的便捷初始值设定项已更改。

convenience init(type buttonType: UIButtonType)

Swift 3:

let btn = UIButton(type: .system) // note the lower case s

Swift 2.x:

let btn = UIButton(type: .System)

Answer 2

在 iOS 9 convenience init 已更改 用于 buttonWithType。您不能使用

let button = UIButton.buttonWithType(UIButtonType.System)

改为使用

 let button = UIButton(type: UIButtonType.System)

语法如下：

Answer 3

iOS 10 Xcode 8.....

    let button = UIButton(type: .system) // note the lower case s
    button.setTitle("Dismiss", for: UIControlState())
    button.backgroundColor = UIColor.white
    let buttonWidth: CGFloat = alertWidth/2
    let buttonHeight: CGFloat = 40
    button.frame = CGRect(x: alertView.center.x - buttonWidth/2, y: alertView.center.y - buttonHeight/2, width: buttonWidth, height: buttonHeight)
    button.addTarget(self, action: #selector(ExampleIIIViewController.dismissAlert), for: UIControlEvents.touchUpInside)

    alertView.addSubview(button)

iOS9 UIButton初始化

iOS 9 UIButton Initialization

ios

swift

uibutton

ios9