在NSString或nsmutablestring中不可能有多种颜色。我听说过一点NSAttributedString,它是在iPad SDK 3.2(或大约3.2)中引入的,并且在iPhone SDK 4.0 beta版中可用。

我想要一根有三种颜色的绳子。

我不使用3个独立的NSString的原因,是因为三个NSAttributedString子字符串的长度经常改变,所以我宁愿,不使用任何计算重新定位3个独立的NSString对象。

如果使用NSAttributedString是可能的,我怎么做以下-(如果不可能使用NSAttributedString,你会怎么做):

编辑: 记住,@"first", @"second"和@"third"随时会被其他字符串替换。所以使用硬编码的NSRange值是行不通的。


当前回答

为了解决这类问题,我在swift中创建了一个名为Atributika的库。

let str = "<r>first</r><g>second</g><b>third</b>".style(tags:
        Style("r").foregroundColor(.red),
        Style("g").foregroundColor(.green),
        Style("b").foregroundColor(.blue)).attributedString

label.attributedText = str

你可以在这里找到它https://github.com/psharanda/Atributika

其他回答

在构建带属性字符串时,我更喜欢使用可变子类,只是为了让事情更简洁。

话虽如此,下面是如何创建一个三色带属性字符串:

NSMutableAttributedString *string = [[NSMutableAttributedString alloc] initWithString:@"firstsecondthird"];
[string addAttribute:NSForegroundColorAttributeName value:[UIColor redColor] range:NSMakeRange(0,5)];
[string addAttribute:NSForegroundColorAttributeName value:[UIColor greenColor] range:NSMakeRange(5,6)];
[string addAttribute:NSForegroundColorAttributeName value:[UIColor blueColor] range:NSMakeRange(11,5)];

在浏览器中输入。警告实现者

显然你不会像这样硬编码。也许你可以这样做:

NSDictionary *wordToColorMapping = ....;  //an NSDictionary of NSString => UIColor pairs
NSMutableAttributedString *string = [[NSMutableAttributedString alloc] initWithString:@""];
for (NSString *word in wordToColorMapping) {
  UIColor *color = [wordToColorMapping objectForKey:word];
  NSDictionary *attributes = [NSDictionary dictionaryWithObject:color forKey:NSForegroundColorAttributeName];
  NSAttributedString *subString = [[NSAttributedString alloc] initWithString:word attributes:attributes];
  [string appendAttributedString:subString];
  [subString release];
}

//display string

这个方法非常简单。

let text = "This is a colorful attributed string"
let attributedText = 
NSMutableAttributedString.getAttributedString(fromString: text)
attributedText.apply(color: .red, subString: "This")
//Apply yellow color on range
attributedText.apply(color: .yellow, onRange: NSMakeRange(5, 4))

更多详情请点击这里; https://github.com/iOSTechHub/AttributedString

斯威夫特4

let combination = NSMutableAttributedString()

var part1 = NSMutableAttributedString()
var part2 = NSMutableAttributedString()
var part3 = NSMutableAttributedString()

let attrRegular = [NSAttributedStringKey.font : UIFont(name: "Palatino-Roman", size: 15)]

let attrBold:Dictionary = [NSAttributedStringKey.font : UIFont(name: "Raleway-SemiBold", size: 15)]

let attrBoldWithColor: Dictionary = [NSAttributedStringKey.font : UIFont(name: "Raleway-SemiBold", size: 15),
                                 NSAttributedStringKey.foregroundColor: UIColor.red]

if let regular = attrRegular as? [NSAttributedStringKey : NSObject]{
    part1 = NSMutableAttributedString(string: "first", attributes: regular)

}
if let bold = attrRegular as? [NSAttributedStringKey : NSObject]{
    part2 = NSMutableAttributedString(string: "second", attributes: bold)
}

if let boldWithColor = attrBoldWithColor as? [NSAttributedStringKey : NSObject]{
    part3 = NSMutableAttributedString(string: "third", attributes: boldWithColor)
}

combination.append(part1)
combination.append(part2)
combination.append(part3)

属性列表请参见这里的NSAttributedStringKey在苹果文档

带属性字符串扩展的更简单的解决方案。

extension NSMutableAttributedString {

    // this function attaches color to string    
    func setColorForText(textToFind: String, withColor color: UIColor) {
        let range: NSRange = self.mutableString.range(of: textToFind, options: .caseInsensitive)
        self.addAttribute(NSAttributedStringKey.foregroundColor, value: color, range: range)
    }

}

试试这个,看看(在Swift 3和4中测试)

let label = UILabel()
label.frame = CGRect(x: 120, y: 100, width: 200, height: 30)
let first = "first"
let second = "second"
let third = "third"
let stringValue = "\(first)\(second)\(third)"  // or direct assign single string value like "firstsecondthird"

let attributedString: NSMutableAttributedString = NSMutableAttributedString(string: stringValue)
attributedString.setColorForText(textToFind: first, withColor: UIColor.red)   // use variable for string "first"
attributedString.setColorForText(textToFind: "second", withColor: UIColor.green) // or direct string like this "second"
attributedString.setColorForText(textToFind: third, withColor: UIColor.blue)
label.font = UIFont.systemFont(ofSize: 26)
label.attributedText = attributedString
self.view.addSubview(label)

以下是预期结果:

我做了一个库,使这更容易。看看ZenCopy吧。

您可以创建Style对象,和/或将它们设置为稍后引用的键。是这样的:

ZenCopy.manager.config.setStyles {
    return [
        "token": Style(
            color: .blueColor(), // optional
            // fontName: "Helvetica", // optional
            fontSize: 14 // optional
        )
    ]
}

然后,你可以很容易地构造字符串和样式,并有参数:)

label.attributedText = attributedString(
                                ["$0 ".style("token") "is dancing with ", "$1".style("token")], 
                          args: ["JP", "Brock"]
)

你也可以很容易地用正则表达式搜索样式!

let atUserRegex = "(@[A-Za-z0-9_]*)"
mutableAttributedString.regexFind(atUserRegex, addStyle: "token")

这将使用'token'样式对前面带有'@'的所有单词进行样式化。(例如@jpmcglone)

我需要仍然得到它工作w/一切NSAttributedString所提供的,但我认为fontName, fontSize和颜色涵盖了它的大部分。期待很快会有很多更新:)

如果你需要,我可以帮你开始。同时也在寻求反馈,所以如果它能让你的生活更轻松,我就说任务完成了。