swift - 在swift中计算从单词到字符串结尾的字符串范围

Question

我有一个 NSMutatableString:

var string: String = "Due in %@ (%@) $%@.\nOverdue! Please pay now %@"
attributedText = NSMutableAttributedString(string: string, attributes: attributes)

如何在 swift 中计算单词 Overdue 的长度和起始索引？

到目前为止我已经尝试过:

let startIndex = attributedText.string.rangeOfString("Overdue")
let range = startIndex..<attributedText.string.finishIndex

// Access the substring.
let substring = value[range]
print(substring)

但它不起作用。

Answer 1

您应该首先生成结果字符串:

let string = String(format: "Due in %@ (%@) $%@.\nOverdue! Please pay now %@", "some date", "something", "15", "some date")

然后使用.disTanceTo获取索引之间的距离；

if let range = string.rangeOfString("Overdue") {
  let start = string.startIndex.distanceTo(range.startIndex)
  let length = range.startIndex.distanceTo(string.endIndex)

  let wordToEndRange = NSRange(location: start, length: length) 
  // This is the range you need

  attributedText.addAttribute(NSForegroundColorAttributeName, 
     value: UIColor.blueColor(), range: wordToEndRange)
}

---

请注意，如果字符串包含表情符号或其他 Unicode 字符，NSRange 将无法正常工作，因此上述解决方案可能无法在这种情况下正常工作。

请查看以下 SO 答案以获得更好的解决方案，该解决方案也涵盖了这种情况:

• https://stackoverflow.com/a/27041376/793428
• https://stackoverflow.com/a/27880748/793428