Swift3.0 无法将类型 'ClosedRange<Index>' 的值转换为类型 'Range<Index>'

Question

我正在尝试将 Swift 2.3 迁移到 3.0，并且 post 转换面临这个问题。任何建议我做错了什么。

Swift 3.0:

override func setValue(_ value: AnyObject?, forKey key: String) {
    let uppercasedFirstCharacter = String(key.characters.first!).uppercased()
    let range = key.startIndex...key.index(key.startIndex, offsetBy: 0)
    let selectorString = key.replacingCharacters(in: range, with: uppercasedFirstCharacter)

    let selector = NSSelectorFromString("set\(selectorString):")
    let responds = self.responds(to: selector)

    if !responds {
        return
    }

Error:

let selectorString = key.replacingCharacters(in: range, with: uppercasedFirstCharacter)
Cannot convert value of type 'ClosedRange<Index>' (aka 'ClosedRange<String.CharacterView.Index>') to expected argument type 'Range<Index>' (aka 'Range<String.CharacterView.Index>')

原代码：Swift2.3

override func setValue(value: AnyObject?, forKey key: String) {
    let uppercasedFirstCharacter = String(key.characters.first!).uppercaseString

    let range = key.startIndex...key.startIndex.advancedBy(0)
    let selectorString = key.stringByReplacingCharactersInRange(range, withString: uppercasedFirstCharacter)

    let selector = NSSelectorFromString("set\(selectorString):")
    let responds = self.respondsToSelector(selector)

    if !responds {
        return
    }

Answer 1

您可以使用 ..< 而不是 ...，因为 range 的类型是 Range<Index> 而不是 ClosedRange<Index>，在这种情况下调用 stringByReplacingCharactersInRange(...) 不会产生错误（注意 offsetBy 增加 1）。

let range = key.startIndex..<key.index(key.startIndex, offsetBy: 1)
// range is now type Range<Index>

现在，我可能是错的，但似乎您只是希望 selectorString 成为第一个字符大写的 key 的版本。您可以使用范围解决方案的替代方法，例如使用 String 扩展解决方案如下：

extension String { 
   var firstCharacterUppercased: String {
        guard case let c = self.characters,
                   let c1 = c.first else { return self }
        return String(c1).uppercased() + String(c.dropFirst())
    }
}

/* example usage */
let key = "fooBar"
let selectorString = key.firstCharacterUppercased

print(selectorString) // FooBar

Answer 2

Swift 3+

override func setValue(_ value: Any?, forKey key: String) {
        let upperCaseFirstCharacter = String(key.characters.first!).uppercased()
        let range = key.startIndex..<key.index(key.startIndex, offsetBy: 1)
        let selectorString = key.replacingCharacters(in: range, with: upperCaseFirstCharacter)

        let selector = NSSelectorFromString("set\(selectorString):")
        let responds = self.responds(to: selector)

        if !responds{
            return
        }
        super.setValue(value, forKey: key)
    }

    init(dictionary: [String: Any]){
        super.init()
        setValuesForKeys(dictionary)
    }

Swift3.0 无法将类型 'ClosedRange<Index>' 的值转换为类型 'Range<Index>'

Swift3.0 Cannot convert value of type 'ClosedRange<Index>' to type 'Range<Index>'

iphone

xcode

swift2

swift3

xcode8

Swift 3.0:

Error:

原代码：Swift2.3