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

在Swift 4中:

let string:NSMutableAttributedString = {

    let mutableString = NSMutableAttributedString(string: "firstsecondthird")

    mutableString.addAttribute(NSForegroundColorAttributeName, value: UIColor.red , range: NSRange(location: 0, length: 5))
    mutableString.addAttribute(NSForegroundColorAttributeName, value: UIColor.green , range: NSRange(location: 5, length: 6))
    mutableString.addAttribute(NSForegroundColorAttributeName, value: UIColor.blue , range: NSRange(location: 11, length: 5))
    return mutableString
}()

print(string)

其他回答

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:

我写了helper来方便地添加属性:

- (void)addColor:(UIColor *)color substring:(NSString *)substring;
- (void)addBackgroundColor:(UIColor *)color substring:(NSString *)substring;
- (void)addUnderlineForSubstring:(NSString *)substring;
- (void)addStrikeThrough:(int)thickness substring:(NSString *)substring;
- (void)addShadowColor:(UIColor *)color width:(int)width height:(int)height radius:(int)radius substring:(NSString *)substring;
- (void)addFontWithName:(NSString *)fontName size:(int)fontSize substring:(NSString *)substring;
- (void)addAlignment:(NSTextAlignment)alignment substring:(NSString *)substring;
- (void)addColorToRussianText:(UIColor *)color;
- (void)addStrokeColor:(UIColor *)color thickness:(int)thickness substring:(NSString *)substring;
- (void)addVerticalGlyph:(BOOL)glyph substring:(NSString *)substring;

https://github.com/shmidt/MASAttributes

你也可以通过CocoaPods安装:pod 'MASAttributes', '~> 1.0.0'

- (void)changeColorWithString:(UILabel *)uilabel stringToReplace:(NSString *) stringToReplace uiColor:(UIColor *) uiColor{
    NSMutableAttributedString *text =
    [[NSMutableAttributedString alloc]
     initWithAttributedString: uilabel.attributedText];

    [text addAttribute: NSForegroundColorAttributeName value:uiColor range:[uilabel.text rangeOfString:stringToReplace]];

    [uilabel setAttributedText: text];

}

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

我认为,使用正则表达式来查找应用属性的范围是一种非常方便的方法。我是这样做的:

NSMutableAttributedString *goodText = [[NSMutableAttributedString alloc] initWithString:articleText];

NSRange range = [articleText rangeOfString:@"\\[.+?\\]" options:NSRegularExpressionSearch|NSCaseInsensitiveSearch];
if (range.location != NSNotFound) {
    [goodText addAttribute:NSFontAttributeName value:[UIFont fontWithName:@"Georgia" size:16] range:range];
    [goodText addAttribute:NSForegroundColorAttributeName value:[UIColor brownColor] range:range];
}

NSString *regEx = [NSString stringWithFormat:@"%@.+?\\s", [self.article.titleText substringToIndex:0]];
range = [articleText rangeOfString:regEx options:NSRegularExpressionSearch|NSCaseInsensitiveSearch];
if (range.location != NSNotFound) {
    [goodText addAttribute:NSFontAttributeName value:[UIFont fontWithName:@"Georgia-Bold" size:20] range:range];
    [goodText addAttribute:NSForegroundColorAttributeName value:[UIColor blueColor] range:range];
}

[self.textView setAttributedText:goodText];

我正在搜索可用属性的列表,但在这里和类引用的第一页中都没有找到它们。所以我决定在这里发布相关信息。

标准属性

带属性字符串支持以下文本的标准属性。如果键不在字典中,则使用下面描述的默认值。

NSString *NSFontAttributeName;
NSString *NSParagraphStyleAttributeName;
NSString *NSForegroundColorAttributeName;
NSString *NSUnderlineStyleAttributeName;
NSString *NSSuperscriptAttributeName;
NSString *NSBackgroundColorAttributeName;
NSString *NSAttachmentAttributeName;
NSString *NSLigatureAttributeName;
NSString *NSBaselineOffsetAttributeName;
NSString *NSKernAttributeName;
NSString *NSLinkAttributeName;
NSString *NSStrokeWidthAttributeName;
NSString *NSStrokeColorAttributeName;
NSString *NSUnderlineColorAttributeName;
NSString *NSStrikethroughStyleAttributeName;
NSString *NSStrikethroughColorAttributeName;
NSString *NSShadowAttributeName;
NSString *NSObliquenessAttributeName;
NSString *NSExpansionAttributeName;
NSString *NSCursorAttributeName;
NSString *NSToolTipAttributeName;
NSString *NSMarkedClauseSegmentAttributeName;
NSString *NSWritingDirectionAttributeName;
NSString *NSVerticalGlyphFormAttributeName;
NSString *NSTextAlternativesAttributeName;

NSAttributedString编程指南

完整的类参考在这里。