setTitle(_ title:String？,for state:UIControlState)where .Normal state？

Question

我在Xcode 8上用iOS10将我的应用更新为Swift 3,我收到错误:

Btn.setTitle('str', forState: .Normal)

.Normal不再是UIControlState的枚举类型.我应该将哪种类型的UIControlState用于此状态？

Apple枚举现在定义为

public struct UIControlState : OptionSet {

   public init(rawValue: UInt)


   public static var highlighted: UIControlState { get } // used when UIControl isHighlighted is set

   public static var disabled: UIControlState { get }

   public static var selected: UIControlState { get } // flag usable by app (see below)

   @available(iOS 9.0, *)
   public static var focused: UIControlState { get } // Applicable only when the screen supports focus

   public static var application: UIControlState { get } // additional flags available for application use

   public static var reserved: UIControlState { get } // flags reserved for internal framework use 
}

Answer 1

像任何其他选项集一样:

button.setTitle("", for: [])

where []代表.normal(.normalis 的值0).

请注意,我们可以在一个调用中使用多个状态:

button.setTitle("", for: [.selected, .disabled])

这就是为什么UIControlState已经变成了一个选项集.