使用Swift從NSString查找String作為NSRange的出現，結果NSRange將在NSAttributedString中使用

Question

我試圖在一個字符串中找到多個字符串的NSRange 。

在下面的代碼中，我使用String.range(of: String, options: , Range)方法來查找Range ，並轉換為NSRange 。 當文本包含多代碼單元unicode字符（例如emoji）時，此轉換將失敗：

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
    }

}

問題：如果我使用NSString.range()查找NSRange ？ 我正在嘗試此操作，但是我的以下代碼在range:部分中有錯誤。

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

我需要幫助來理解和糾正以上錯誤，謝謝。

Answer 1

找到了將Range轉換為NSRange的正確方法，這要感謝MartinR的回答

我使用了錯誤的方式將Range轉換為NSRange ，這是工作代碼片段，其中包含將Range轉換為NSRange正確方法：

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
    }

}