我正在将现有应用从Swift 3
转换为Swift 4
。它给出了错误:
'串(来自:)'不推荐使用:请使用字符串切片下标,其中'部分范围来自'操作
和
'字符'不推荐使用:请直接使用String或Substring
我的Swift 3
代码是:
public convenience init?(hexString: String, alpha: Float) {
var hex = hexString
// Check for hash and remove the hash
if hex.hasPrefix("#") {
hex = hex.substring(from: hex.characters.index(hex.startIndex, offsetBy: 1))
}
if (hex.range(of: "(^[0-9A-Fa-f]{6}$)|(^[0-9A-Fa-f]{3}$)", options: .regularExpression) != nil) {
// Deal with 3 character Hex strings
if hex.characters.count == 3 {
let redHex = hex.substring(to: hex.characters.index(hex.startIndex, offsetBy: 1))
let greenHex = hex.substring(with: (hex.characters.index(hex.startIndex, offsetBy: 1) ..< hex.characters.index(hex.startIndex, offsetBy: 2)))
let blueHex = hex.substring(from: hex.characters.index(hex.startIndex, offsetBy: 2))
hex = redHex + redHex + greenHex + greenHex + blueHex + blueHex
}
let redHex = hex.substring(to: hex.characters.index(hex.startIndex, offsetBy: 2))
let greenHex = hex.substring(with: (hex.characters.index(hex.startIndex, offsetBy: 2) ..< hex.characters.index(hex.startIndex, offsetBy: 4)))
let blueHex = hex.substring(with: (hex.characters.index(hex.startIndex, offsetBy: 4) ..< hex.characters.index(hex.startIndex, offsetBy: 6)))
var redInt: CUnsignedInt = 0
var greenInt: CUnsignedInt = 0
var blueInt: CUnsignedInt = 0
Scanner(string: redHex).scanHexInt32(&redInt)
Scanner(string: greenHex).scanHexInt32(&greenInt)
Scanner(string: blueHex).scanHexInt32(&blueInt)
self.init(red: CGFloat(redInt) / 255.0, green: CGFloat(greenInt) / 255.0, blue: CGFloat(blueInt) / 255.0, alpha: CGFloat(alpha))
}
else {
self.init()
return nil
}
}
如何将其转换为 Swift 4 ?
答案 0 :(得分:2)
'characters':请直接使用String或Substring
为此,您可以直接在swift 4中循环遍历字符串,因此不需要字符数组。
而
'substring(from :)'已被弃用:请使用字符串切片下标和'partial range from'运算符。