distance(from：to :)’不可用：任何String视图索引转换都可能在Swift 4中失败;请打开可选索引

概述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: Ran 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.same@R_419_4612@(in: utf16vIEw)    let to = range.upperBound.same@R_419_4612@(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.same@R_419_4612@(in: utf16vIEw),let to = range.upperBound.same@R_419_4612@(in: utf16vIEw) {       return NSMakeRange(utf16vIEw.distance(from: utf16vIEw.startIndex,utf16vIEw.distance(from: from,to: to))    }    return nil}

总结

以上是内存溢出为你收集整理的distance(from：to :)’不可用：任何String视图索引转换都可能在Swift 4中失败;请打开可选索引全部内容，希望文章能够帮你解决distance(from：to :)’不可用：任何String视图索引转换都可能在Swift 4中失败;请打开可选索引所遇到的程序开发问题。

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