使用iOS 8中的NSMutableAttributedString对字符串的下划线部分无效

Question

我尝试为字符串的一部分加下划线,例如,' test string '字符串中的' string '部分.我正在使用,我的解决方案运作良好.NSMutableAttributedStringiOS7

NSMutableAttributedString *attributedString = [[NSMutableAttributedString alloc]
        initWithString:@"test string"];
[attributedString addAttribute:NSUnderlineStyleAttributeName
                         value:@(NSUnderlineStyleSingle)
                         range:NSMakeRange(5, 6)];
myLabel.attributedText = attributedString;

问题是我的解决方案iOS8不再适用了.在花了一个小时测试多个变体之后NSMutableAttributedString,我发现这个解决方案只在范围从0开始时才有效(长度可以不同).这是什么原因？我该如何解决这个问题？

Answer 1

更新: 通过调查此问题:在iOS 8上显示NSMutableAttributedString我终于找到了解决方案!

您应该在字符串的开头添加NSUnderlineStyleNone.

Swift 4.2(none已删除):

let attributedString = NSMutableAttributedString()
attributedString.append(NSAttributedString(string: "test ",
                                           attributes: [.underlineStyle: 0]))
attributedString.append(NSAttributedString(string: "s",
                                           attributes: [.underlineStyle: NSUnderlineStyle.single.rawValue]))
attributedString.append(NSAttributedString(string: "tring",
                                           attributes: [.underlineStyle: 0]))

Objective-C的:

 NSMutableAttributedString *attributedString = [[NSMutableAttributedString alloc] init];
 [attributedString appendAttributedString:[[NSAttributedString alloc] initWithString:@"test "
                                                                          attributes:@{NSUnderlineStyleAttributeName: @(NSUnderlineStyleNone)}]];
 [attributedString appendAttributedString:[[NSAttributedString alloc] initWithString:@"s"
                                                                         attributes:@{NSUnderlineStyleAttributeName: @(NSUnderlineStyleSingle),
                                                                                      NSBackgroundColorAttributeName: [UIColor clearColor]}]];
 [attributedString appendAttributedString:[[NSAttributedString alloc] initWithString:@"tring"]];

这种方法的另一个好处是没有任何范围.非常适合本地化的字符串.

好像是苹果虫:(

Answer 2

我发现如果你将UnderlineStyleNone应用于整个字符串,你可以选择性地将下划线应用于从中间开始的部分:

func underlinedString(string: NSString, term: NSString) -> NSAttributedString {
    let output = NSMutableAttributedString(string: string)
    let underlineRange = string.rangeOfString(term)
    output.addAttribute(NSUnderlineStyleAttributeName, value: NSUnderlineStyle.StyleNone.rawValue, range: NSMakeRange(0, string.length))
    output.addAttribute(NSUnderlineStyleAttributeName, value: NSUnderlineStyle.StyleSingle.rawValue, range: underlineRange)

    return output
}

Answer 3

NSMutableAttributedString *signUpString = [[NSMutableAttributedString alloc] initWithString:@"Not a member yet?Sign Up now"];

[signUpString appendAttributedString:[[NSAttributedString alloc] initWithString:@" "attributes:@{NSUnderlineStyleAttributeName: @(NSUnderlineStyleNone)}]];

[signUpString addAttributes: @{NSForegroundColorAttributeName:UIColorFromRGB(0x43484B),NSUnderlineStyleAttributeName:[NSNumber numberWithInteger:NSUnderlineStyleSingle]} range:NSMakeRange(17,11)];

signUpLbl.attributedText = [signUpString copy];

它对我有用

Answer 4

现在是 2018 年 9 月，所以这个答案与 iOS8 无关，但它仍然与字符串的下划线部分有关。

这是一个Swift 4扩展，它强调了一个已经组成的术语中的给定术语myAttributedString

extension NSMutableAttributedString {

    func underline(term: String) {

        guard let underlineRange = string.range(of: term) else {

            return
        }

        let startPosition = string.distance(from: term.startIndex, to: underlineRange.lowerBound)
        let nsrange = NSRange(location: startPosition, length: term.count)

        addAttribute(
            .underlineStyle,
            value: NSUnderlineStyle.styleSingle.rawValue,
            range: nsrange)
    }
}

用法： myAttributedString.underline(term: "some term")