NSMutableAttributedString 的可变大小范围

Question

我有一个标签，其字符串如下所示。我希望 secondVariable 是不同的颜色。我想我明白如何改变颜色。我的问题是获取 secondVariable.

的范围

let str = "\(firstVariable) some random text \(secondVariable)"

let secondVariableRange = str.range(???) 
let secondVariableNSRange = NSRange(secondVariableRange, in: str)

let attributedString = NSMutableAttributedString.init(string: 
    "\(firstVariable) some random text \(secondVariable)")

attributedString.addAttribute(.foregroundColor, value: UIColor.white, 
    range: NSRange(secondVariableNSRange, in: attributedString)

Answer 1

有一种比处理范围更简单的方法。分段构建您的属性字符串。

let attributedString = NSMutableAttributedString(string: 
"\(firstVariable) some random text ")
let attrs: [NSAttributedStringKey : Any] = [ .foregroundColor: UIColor.white ]
let secondString = NSAttributedString(string: "\(secondVariable)", attributes: attrs)
attributedString.append(secondString)

但是如果你真的想得到范围，使用：

let secondVariableRange = (str as NSString).range(of: "\(secondVariable)")

NSMutableAttributedString 的可变大小范围

Variable sized range for NSMutableAttributedString

range

nsmutableattributedstring

swift

swift4