我试图将我的应用程序迁移到
Swift 4,Xcode 9.我收到此错误.它来自第三方框架.
distance(from:to:)’ is unavailable: Any String view index conversion can fail in Swift 4; please unwrap the optional indices
func nsRange(from range: Range<String.Index>) -> NSRange {
let utf16view = self.utf16
let from = range.lowerBound.samePosition(in: utf16view)
let to = range.upperBound.samePosition(in: utf16view)
return NSMakeRange(utf16view.distance(from: utf16view.startIndex,to: from),// Error: distance(from:to:)' is unavailable: Any String view index conversion can fail in Swift 4; please unwrap the optional indices
utf16view.distance(from: from,to: to))// Error: distance(from:to:)' is unavailable: Any String view index conversion can fail in Swift 4; please unwrap the optional indices
}
你可以简单地打开这样的可选索引：
func nsRange(from range: Range<String.Index>) -> NSRange? {
let utf16view = self.utf16
if let from = range.lowerBound.samePosition(in: utf16view),let to = range.upperBound.samePosition(in: utf16view) {
return NSMakeRange(utf16view.distance(from: utf16view.startIndex,utf16view.distance(from: from,to: to))
}
return nil
}
