NSRange 来自 Swift Range？

Question

问题： NSAttributedString 需要一个 NSRange，而我使用的是使用 Range 的 Swift 字符串

let text = "Long paragraph saying something goes here!"
let textRange = text.startIndex..<text.endIndex
let attributedString = NSMutableAttributedString(string: text)

text.enumerateSubstringsInRange(textRange, options: NSStringEnumerationOptions.ByWords, { (substring, substringRange, enclosingRange, stop) -> () in

    if (substring == "saying") {
        attributedString.addAttribute(NSForegroundColorAttributeName, value: NSColor.redColor(), range: substringRange)
    }
})

产生以下错误：

错误：“范围”不能转换为“NSRange” attributesString.addAttribute(NSForegroundColorAttributeName, value: NSColor.redColor(), range: substringRange)

Answer 1

Swift String 范围和 NSString 范围不“兼容”。 例如，像? 这样的表情符号算作一个 Swift 字符，但算作两个 NSString 字符（所谓的 UTF-16 代理对）。

因此，如果字符串 包含这样的字符。示例：

let text = "???Long paragraph saying!"
let textRange = text.startIndex..<text.endIndex
let attributedString = NSMutableAttributedString(string: text)

text.enumerateSubstringsInRange(textRange, options: NSStringEnumerationOptions.ByWords, { (substring, substringRange, enclosingRange, stop) -> () in
    let start = distance(text.startIndex, substringRange.startIndex)
    let length = distance(substringRange.startIndex, substringRange.endIndex)
    let range = NSMakeRange(start, length)

    if (substring == "saying") {
        attributedString.addAttribute(NSForegroundColorAttributeName, value: NSColor.redColor(), range: range)
    }
})
println(attributedString)

输出：

???长段落{ }ph 说{ NSColor = "NSCalibratedRGBColorSpace 1 0 0 1"; }ing！{ }

如您所见，“ph say”已被标记为属性，而不是“saying”。

由于NS(Mutable)AttributedString 最终需要一个NSString 和一个NSRange，它实际上是 最好先将给定的字符串转换为NSString。然后substringRange 是NSRange，您不必再转换范围：

let text = "???Long paragraph saying!"
let nsText = text as NSString
let textRange = NSMakeRange(0, nsText.length)
let attributedString = NSMutableAttributedString(string: nsText)

nsText.enumerateSubstringsInRange(textRange, options: NSStringEnumerationOptions.ByWords, { (substring, substringRange, enclosingRange, stop) -> () in

    if (substring == "saying") {
        attributedString.addAttribute(NSForegroundColorAttributeName, value: NSColor.redColor(), range: substringRange)
    }
})
println(attributedString)

输出：

???长段{ }说{ NSColor = "NSCalibratedRGBColorSpace 1 0 0 1"; }!{ }

Swift 2 更新：

let text = "???Long paragraph saying!"
let nsText = text as NSString
let textRange = NSMakeRange(0, nsText.length)
let attributedString = NSMutableAttributedString(string: text)

nsText.enumerateSubstringsInRange(textRange, options: .ByWords, usingBlock: {
    (substring, substringRange, _, _) in

    if (substring == "saying") {
        attributedString.addAttribute(NSForegroundColorAttributeName, value: NSColor.redColor(), range: substringRange)
    }
})
print(attributedString)

Swift 3 更新：

let text = "???Long paragraph saying!"
let nsText = text as NSString
let textRange = NSMakeRange(0, nsText.length)
let attributedString = NSMutableAttributedString(string: text)

nsText.enumerateSubstrings(in: textRange, options: .byWords, using: {
    (substring, substringRange, _, _) in

    if (substring == "saying") {
        attributedString.addAttribute(NSForegroundColorAttributeName, value: NSColor.red, range: substringRange)
    }
})
print(attributedString)

Swift 4 更新：

从 Swift 4 (Xcode 9) 开始，Swift 标准库 提供在Range<String.Index> 和NSRange 之间转换的方法。 不再需要转换为NSString：

let text = "???Long paragraph saying!"
let attributedString = NSMutableAttributedString(string: text)

text.enumerateSubstrings(in: text.startIndex..<text.endIndex, options: .byWords) {
    (substring, substringRange, _, _) in
    if substring == "saying" {
        attributedString.addAttribute(.foregroundColor, value: NSColor.red,
                                      range: NSRange(substringRange, in: text))
    }
}
print(attributedString)

这里substringRange 是一个Range<String.Index>，它被转换为 对应NSRange与

NSRange(substringRange, in: text)

Answer 2

对于您所描述的情况，我发现这是可行的。它相对简短而甜美：

 let attributedString = NSMutableAttributedString(string: "follow the yellow brick road") //can essentially come from a textField.text as well (will need to unwrap though)
 let text = "follow the yellow brick road"
 let str = NSString(string: text) 
 let theRange = str.rangeOfString("yellow")
 attributedString.addAttribute(NSForegroundColorAttributeName, value: UIColor.yellowColor(), range: theRange)

Answer 3

答案很好，但使用 Swift 4 您可以稍微简化代码：

let text = "Test string"
let substring = "string"

let substringRange = text.range(of: substring)!
let nsRange = NSRange(substringRange, in: text)

小心，range 函数的结果必须被解包。

Answer 4

可能的解决方案

Swift 提供了 distance() 来测量 start 和 end 之间的距离，可以用来创建一个 NSRange：

let text = "Long paragraph saying something goes here!"
let textRange = text.startIndex..<text.endIndex
let attributedString = NSMutableAttributedString(string: text)

text.enumerateSubstringsInRange(textRange, options: NSStringEnumerationOptions.ByWords, { (substring, substringRange, enclosingRange, stop) -> () in
    let start = distance(text.startIndex, substringRange.startIndex)
    let length = distance(substringRange.startIndex, substringRange.endIndex)
    let range = NSMakeRange(start, length)

//    println("word: \(substring) - \(d1) to \(d2)")

        if (substring == "saying") {
            attributedString.addAttribute(NSForegroundColorAttributeName, value: NSColor.redColor(), range: range)
        }
})

Answer 5

对我来说这很完美：

let font = UIFont.systemFont(ofSize: 12, weight: .medium)
let text = "text"
let attString = NSMutableAttributedString(string: "exemple text :)")

attString.addAttributes([.font: font], range:(attString.string as NSString).range(of: text))

label.attributedText = attString

Answer 6

斯威夫特 4：

当然，我知道 Swift 4 已经有了 NSRange 的扩展

public init<R, S>(_ region: R, in target: S) where R : RangeExpression,
    S : StringProtocol, 
    R.Bound == String.Index, S.Index == String.Index

我知道在大多数情况下这个初始化就足够了。查看其用法：

let string = "Many animals here: ??? !!!"

if let range = string.range(of: "???"){
     print((string as NSString).substring(with: NSRange(range, in: string))) //  "???"
 }

但是可以直接从 Range 转换到 NSRange，而不需要 Swift 的 String 实例。

而不是一般的 init 用法，它需要您将 target 参数作为 String 和 如果您手头没有 target 字符串，您可以直接创建转换

extension NSRange {
    public init(_ range:Range<String.Index>) {
        self.init(location: range.lowerBound.encodedOffset,
              length: range.upperBound.encodedOffset -
                      range.lowerBound.encodedOffset) }
    }

或者您可以为 Range 本身创建专门的扩展

extension Range where Bound == String.Index {
    var nsRange:NSRange {
    return NSRange(location: self.lowerBound.encodedOffset,
                     length: self.upperBound.encodedOffset -
                             self.lowerBound.encodedOffset)
    }
}

用法：

let string = "Many animals here: ??? !!!"
if let range = string.range(of: "???"){
    print((string as NSString).substring(with: NSRange(range))) //  "???"
}

或

if let nsrange = string.range(of: "???")?.nsRange{
    print((string as NSString).substring(with: nsrange)) //  "???"
}

斯威夫特 5：

由于默认将 Swift 字符串迁移到 UTF-8 编码，encodedOffset 的使用被认为已弃用，如果没有 String 本身的实例，Range 无法转换为 NSRange，因为为了计算偏移量，我们需要以 UTF-8 编码的源字符串，在计算偏移量之前应将其转换为 UTF-16。所以目前最好的方法是使用通用 init。

Answer 7

斯威夫特 4

我认为，有两种方法。

1. NSRange(范围，在：)

2。 NSRange（位置：，长度：）

示例代码：

let attributedString = NSMutableAttributedString(string: "Sample Text 12345", attributes: [.font : UIFont.systemFont(ofSize: 15.0)])

// NSRange(range, in: )
if let range = attributedString.string.range(of: "Sample")  {
    attributedString.addAttribute(.foregroundColor, value: UIColor.orange, range: NSRange(range, in: attributedString.string))
}

// NSRange(location: , length: )
if let range = attributedString.string.range(of: "12345") {
    attributedString.addAttribute(.foregroundColor, value: UIColor.green, range: NSRange(location: range.lowerBound.encodedOffset, length: range.upperBound.encodedOffset - range.lowerBound.encodedOffset))
}

屏幕截图：

Answer 8

Swift 5 解决方案

将 Range 转换为 NSRange

由于 'encodedOffset' 已被弃用，所以现在为了将 String.Index 转换为 Int 我们需要原始字符串的引用Range 的来源。

NSRange 的一个方便的详细扩展可能如下：

extension NSRange {

    public init(range: Range<String.Index>, 
                originalText: String) {

        let range_LowerBound_INDEX = range.lowerBound
        let range_UpperBound_INDEX = range.upperBound

        let range_LowerBound_INT = range_LowerBound_INDEX.utf16Offset(in: originalText)
        let range_UpperBound_INT = range_UpperBound_INDEX.utf16Offset(in: originalText)

        let locationTemp = range_LowerBound_INT
        let lengthTemp = range_UpperBound_INT - range_LowerBound_INT

        self.init(location: locationTemp,
                  length: lengthTemp)
    }
}

虽然简写扩展如下

extension NSRange {

    public init(range: Range<String.Index>, 
                originalText: String) {

        self.init(location: range.lowerBound.utf16Offset(in: originalText),
                  length: range.upperBound.utf16Offset(in: originalText) - range.lowerBound.utf16Offset(in: originalText))
    }
}

现在我们可以使用任何 Range 将其转换为 NSRange，如下所示，分享我自己的需求，这导致我编写上述扩展

我使用下面的字符串扩展来从字符串中查找特定单词的所有范围

extension String {
        
    func ranges(of substring: String, options: CompareOptions = [], locale: Locale? = nil) -> [Range<Index>] {
        var ranges: [Range<Index>] = []
        while let range = range(of: substring, options: options, range: (ranges.last?.upperBound ?? self.startIndex)..<self.endIndex, locale: locale) {
            ranges.append(range)
        }
        return ranges
    }
}

我的要求是更改字符串中特定单词的颜色，为此我编写了这个扩展来完成这项工作

extension NSAttributedString {

    static func colored(originalText:String,
                        wordToColor:String,
                        currentColor:UIColor,
                        differentColor:UIColor) -> NSAttributedString {
        
        let attr = NSMutableAttributedString(string: originalText)
        
        attr.beginEditing()
        
        attr.addAttribute(NSAttributedString.Key.foregroundColor,
                          value: currentColor,
                          range: NSRange(location: 0, length: originalText.count))
        
        // FOR COVERING ALL THE OCCURENCES
        for eachRange in originalText.ranges(of: wordToColor) {
            attr.addAttribute(NSAttributedString.Key.foregroundColor,
                              value: differentColor,
                              range: NSRange(range: eachRange, originalText: originalText))
        }
        
        attr.endEditing()
        
        return attr
    }

}

最后我在下面的主代码中使用它

let text = "Collected".localized() + "  +  " + "Cancelled".localized() + "  +  " + "Pending".localized()
myLabel.attributedText = NSAttributedString.colored(originalText: text,
                                                    wordToColor: "+",
                                                    currentColor: UIColor.purple,
                                                    differentColor: UIColor.blue)

结果如下，+号的颜色从正文的紫色变为蓝色。

希望这可以帮助有需要的人。谢谢！

Answer 9

Swift 3 Extension Variant 保留现有属性。

extension UILabel {
  func setLineHeight(lineHeight: CGFloat) {
    guard self.text != nil && self.attributedText != nil else { return }
    var attributedString = NSMutableAttributedString()

    if let attributedText = self.attributedText {
      attributedString = NSMutableAttributedString(attributedString: attributedText)
    } else if let text = self.text {
      attributedString = NSMutableAttributedString(string: text)
    }

    let style = NSMutableParagraphStyle()
    style.lineSpacing = lineHeight
    style.alignment = self.textAlignment
    let str = NSString(string: attributedString.string)

    attributedString.addAttribute(NSParagraphStyleAttributeName,
                                  value: style,
                                  range: str.range(of: str as String))
    self.attributedText = attributedString
  }
}

Answer 10

func formatAttributedStringWithHighlights(text: String, highlightedSubString: String?, formattingAttributes: [String: AnyObject]) -> NSAttributedString {
    let mutableString = NSMutableAttributedString(string: text)

    let text = text as NSString         // convert to NSString be we need NSRange
    if let highlightedSubString = highlightedSubString {
        let highlightedSubStringRange = text.rangeOfString(highlightedSubString) // find first occurence
        if highlightedSubStringRange.length > 0 {       // check for not found
            mutableString.setAttributes(formattingAttributes, range: highlightedSubStringRange)
        }
    }

    return mutableString
}

Answer 11

我的解决方案是字符串扩展，首先获取快速范围，然后获取从字符串开头到子字符串开头和结尾的距离。

这些值随后用于计算子字符串的开始和长度。然后我们可以将这些值应用到 NSMakeRange 构造函数。

此解决方案适用于由多个单词组成的子字符串，这里的许多使用 enumerateSubstrings 的解决方案让我失望。

extension String {

    func NSRange(of substring: String) -> NSRange? {
        // Get the swift range 
        guard let range = range(of: substring) else { return nil }

        // Get the distance to the start of the substring
        let start = distance(from: startIndex, to: range.lowerBound) as Int
        //Get the distance to the end of the substring
        let end = distance(from: startIndex, to: range.upperBound) as Int

        //length = endOfSubstring - startOfSubstring
        //start = startOfSubstring
        return NSMakeRange(start, end - start)
    }

}

Answer 12

我喜欢 Swift 语言，但是将 NSAttributedString 与与 NSRange 不兼容的 Swift Range 一起使用让我头疼了太久。因此，为了解决所有这些垃圾问题，我设计了以下方法来返回一个NSMutableAttributedString，其中突出显示的单词设置为您的颜色。

这不适用于表情符号。必要时进行修改。

extension String {
    func getRanges(of string: String) -> [NSRange] {
        var ranges:[NSRange] = []
        if contains(string) {
            let words = self.components(separatedBy: " ")
            var position:Int = 0
            for word in words {
                if word.lowercased() == string.lowercased() {
                    let startIndex = position
                    let endIndex = word.characters.count
                    let range = NSMakeRange(startIndex, endIndex)
                    ranges.append(range)
                }
                position += (word.characters.count + 1) // +1 for space
            }
        }
        return ranges
    }
    func highlight(_ words: [String], this color: UIColor) -> NSMutableAttributedString {
        let attributedString = NSMutableAttributedString(string: self)
        for word in words {
            let ranges = getRanges(of: word)
            for range in ranges {
                attributedString.addAttributes([NSForegroundColorAttributeName: color], range: range)
            }
        }
        return attributedString
    }
}

用法：

// The strings you're interested in
let string = "The dog ran after the cat"
let words = ["the", "ran"]

// Highlight words and get back attributed string
let attributedString = string.highlight(words, this: .yellow)

// Set attributed string
label.attributedText = attributedString

Answer 13

let text:String = "Hello Friend"

let searchRange:NSRange = NSRange(location:0,length: text.characters.count)

let range:Range`<Int`> = Range`<Int`>.init(start: searchRange.location, end: searchRange.length)