如何在swift中使用NSAttributedString的replacementOccurrences？

Question

在NSAttributed类型语句中，我希望保留现有的属性值并为其赋予新的属性值。

问题是replacingOccurrences只能用于字符串类型，因为我想在每个单词出现在整个句子中时给出一个新值。

如果我将NSAttributedString更改为字符串类型，则会删除属性值。我必须保留现有的价值观。

我该怎么做？

Answer 1

您可以使用replaceCharacters。您可以找到要删除的子字符串的范围，并将其用作范围。

Answer 2

要实现这一目标，

1。首先，您需要查找字符串中存在的所有重复子字符串的索引。为此，您可以使用：https://stackoverflow.com/a/40413665/5716829

extension String {
    func indicesOf(string: String) -> [Int] {
        var indices = [Int]()
        var searchStartIndex = self.startIndex

        while searchStartIndex < self.endIndex,
            let range = self.range(of: string, range: searchStartIndex..<self.endIndex),
            !range.isEmpty
        {
            let index = distance(from: self.startIndex, to: range.lowerBound)
            indices.append(index)
            searchStartIndex = range.upperBound
        }

        return indices
    }
}

2. 接下来，您需要在每个索引处将所需属性应用于子字符串，即

    let str = "The problem is that replacingOccurrences Hello is only possible for string types, as I want to give Hello a new value every time Hello the word appears in the entire sentence Hello."
    let indices = str.indicesOf(string: "Hello")
    let attrStr = NSMutableAttributedString(string: str, attributes: [.foregroundColor : UIColor.blue])
    for index in indices
    {
        //You can write your own logic to specify the color for each duplicate. I have used some hardcode indices
        var color: UIColor
        switch index
        {
        case 41:
            color = .orange
        case 100:
            color = .magenta
        case 129:
            color = .green
        default:
            color = .red
        }
        attrStr.addAttribute(.foregroundColor, value: color, range: NSRange(location: index, length: "Hello".count))
    }

<强>截图：

如果您仍然遇到任何问题，请告诉我。快乐的编码..