来自Swift Range的NSRange？

对于像你描述的那样的情况,我发现这是有用的.它相对简短而且甜美: letattributedString=NSMutableAttributedString(string:followtheyellowbrickroad)//canessentiallycomefromatextField.textaswell(willneedtounwrapthough) lettext=followtheyellowbrickroad letstr=NSString(string:text) lettheRange=str.rangeOfString(yellow) attributedString.addAttribute(NSForegroundColorAttributeName,value:UIColor.yellowColor(),range:theRange)

可能解决方案

Swift提供distance(),用于测量可用于创建NSRange的start和end之间的距离:

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)
        }
})

斯威夫特4:

当然,我知道Swift 4已经扩展了NSRange

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.看它的用法:

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

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

但转换可以直接从Range <String.Index>到NSRange完成而不需要Swift的String实例.

而不是通用的init用法,它要求您将目标参数作为String,如果您没有目标字符串,则可以直接创建转换

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))) //  ""
}

要么

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

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

Swift String范围和NSString范围不是"兼容的".例如,表情符号就像一个Swift字符,但是作为两个NSString 字符(所谓的UTF-16代理对).

因此,如果字符串包含此类字符,则建议的解决方案将产生意外结果 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:

Long paragra{
}ph say{
    NSColor = "NSCalibratedRGBColorSpace 1 0 0 1";
}ing!{
}

如你所见,"ph say"已经标有属性,而不是"说".

由于NS(Mutable)AttributedString最终需要a NSString和a NSRange,实际上最好将给定的字符串转换为NSString第一个.然后substringRange 是一个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:

Long paragraph {
}saying{
    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的更新:

从Swift 4(Xcode 9)开始,Swift标准库提供了在Range<String.Index>和之间进行转换的方法NSRange.NSString不再需要转换为:

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substringRange是一个Range<String.Index>,并将其转换为相应NSRange的

NSRange(substringRange, in: text)

答案很好,但使用Swift 4可以简化代码:

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

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

请注意,因为range功能的结果必须打开.