使用Swift从NSString查找String作为NSRange的出现，结果NSRange将在NSAttributedString中使用

Question

我试图在一个字符串中找到多个字符串的NSRange 。

在下面的代码中，我使用String.range(of: String, options: , Range)方法来查找Range ，并转换为NSRange 。 当文本包含多代码单元unicode字符（例如emoji）时，此转换将失败：

let findInString = "This #is a #tag #tag inten#sive🔦#search" // MAY CONTAINS EMOJIS
let findStrings = ["#is","#tag","#sive","#search"]
let result = NSMutableAttributedString(string: findInString)

for (index, stringToFind) in findStrings.enumerated() {

    var nextStartIndex = findInString.startIndex

    while let range = findInString.range(of: stringToFind, options: [.literal, .caseInsensitive], range: nextStartIndex..<findInString.endIndex) {

        let start = findInString.distance(from: findInString.startIndex, to: range.lowerBound)
        let length = findInString.distance(from: range.lowerBound, to: range.upperBound)

        result.addAttribute(NSLinkAttributeName, value: "\(index):", range: NSMakeRange(start, length))

        nextStartIndex = range.upperBound
    }

}

问题：如果我使用NSString.range()查找NSRange ？ 我正在尝试此操作，但是我的以下代码在range:部分中有错误。

let findInNsString = findInString as NSString
while let range = findInNsString.range(of: stringToFind, options: [.literal, .caseInsensitive], range: nextStartIndex..<findInString.endIndex)

我需要帮助来理解和纠正以上错误，谢谢。

Answer 1

找到了将Range转换为NSRange的正确方法，这要感谢MartinR的回答

我使用了错误的方式将Range转换为NSRange ，这是工作代码片段，其中包含将Range转换为NSRange正确方法：

let findStrings = ["#is","#tag","#siØve","#search"]
let findInString = "This #is a #tag #tag inten#siØve🔦#search"
let result = NSMutableAttributedString(string: findInString)
let utf16 = findInString.utf16
for (index, stringToFind) in findStrings.enumerated() {

    var nextStartIndex = findInString.startIndex

    while let range = findInString.range(of: stringToFind, options: [.literal, .caseInsensitive], range: nextStartIndex..<findInString.endIndex) {

        // PROPER WAY TO CONVERT TO NSRange
        let from = range.lowerBound.samePosition(in: utf16)
        let start = utf16.distance(from: utf16.startIndex, to: from)
        let length = utf16.distance(from: from, to: range.upperBound.samePosition(in: utf16))

        result.addAttribute(NSLinkAttributeName, value: "\(index):", range: NSMakeRange(start, length))

        nextStartIndex = range.upperBound
    }

}