UIControlState.Normal is Unavailable

问题

Previously for UIButton instances, you were able to pass in UIControlState.Normal for setTitle or setImage. .Normal is no longer available, what should I use instead?

let btn = UIButton(frame: CGRect(x: 0, y: 0, width: 20, height: 20))
btn.setTitle("title", for: .Normal) // does not compile

^{(This is a canonical Q&A pair to prevent the flood of duplicate questions related to this UIButton and UIControl changes with iOS 10 and Swift 3)}

回答1:

Swift 3 update:

It appears that Xcode 8/Swift 3 brought UIControlState.normal back:

public struct UIControlState : OptionSet {

    public init(rawValue: UInt)


    public static var normal: UIControlState { get }

    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
}

UIControlState.Normal has been renamed to UIControlState.normal and removed from the iOS SDK. For "Normal" options, use an empty array to construct an empty option set.

let btn = UIButton(frame: CGRect(x: 0, y: 0, width: 20, height: 20))

// Does not work
btn.setTitle("title", for: .Normal) // 'Normal' has been renamed to 'normal'
btn.setTitle("title", for: .normal) // 'normal' is unavailable: use [] to construct an empty option set

// Works
btn.setTitle("title", for: [])

回答2:

The .Normal is removed(iOS 10 DP1), you can use the [] or UIControlState(rawValue: UInt(0)) to replace the .Normal, if you don't want to change codes all around(in case apple add it again or you don't like the []), you can just add once this code

extension UIControlState {
    public static var Normal: UIControlState { return [] }
}

or

extension UIControlState {
    public static var Normal: UIControlState { return UIControlState(rawValue: UInt(0)) }
}

then all the .Normal work like before.

回答3:

Apple brought back the normal control state in more recent versions of Xcode beta. Upgrade to the most recent Xcode beta and use .normal.

回答4:

Swift 5

Replace from

btn.setTitle("title", for: .Normal)

to

btn.setTitle("title", for: UIControl.State.normal)

来源：https://stackoverflow.com/questions/37800342/uicontrolstate-normal-is-unavailable