许多应用程序都有文本,文本中是圆角矩形的web超链接,当我点击它们时,UIWebView就会打开。让我困惑的是,他们经常有自定义链接,例如,如果单词以#开头,它也是可点击的,应用程序通过打开另一个视图来响应。我该怎么做呢?是否可以用UILabel或者我需要UITextView或者其他什么?


当前回答

对于完全自定义的链接,你需要使用UIWebView -你可以拦截调用,这样当链接被按下时,你可以转到应用程序的其他部分。

其他回答

是的,这是可能的,尽管一开始很困惑。我将进一步向您展示如何甚至可以单击文本中的任何区域。

使用这个方法,你可以有一个UI标签,如下所示:

多行友好 Autoshrink友好 可点击友好型(是的,甚至是单个角色) 斯威夫特5

步骤1:

使UILabel具有'Truncate Tail'的换行属性,并设置最小字体比例。

如果你不熟悉字体比例,请记住以下规则:

minimumFontSize/defaultFontSize = fontscale

在我的例子中,我希望7.2是最小字体大小,而我的起始字体大小是36。因此7.2 / 36 = 0.2

步骤2:

如果你不关心标签是可点击的,只是想要一个工作多行标签你就完成了!

然而,如果你想要标签是可点击阅读…

添加以下扩展我创建

extension UILabel {

    func setOptimalFontSize(maxFontSize:CGFloat,text:String){
        let width = self.bounds.size.width

        var font_size:CGFloat = maxFontSize //Set the maximum font size.
        var stringSize = NSString(string: text).size(withAttributes: [.font : self.font.withSize(font_size)])
        while(stringSize.width > width){
            font_size = font_size - 1
            stringSize = NSString(string: text).size(withAttributes: [.font : self.font.withSize(font_size)])
        }

        self.font = self.font.withSize(font_size)//Forcefully change font to match what it would be graphically.
    }
}

它的用法是这样的(只需将<Label>替换为您实际的标签名):

<Label>.setOptimalFontSize(maxFontSize: 36.0, text: formula)

这个扩展是需要的,因为自动收缩不会改变标签的'字体'属性后,它自动收缩,所以你必须通过计算它通过使用.size(withAttributes)函数模拟它的大小将与特定的字体。

这是必要的,因为检测在标签上单击的位置的解决方案需要知道确切的字体大小。

步骤3:

添加以下扩展名:

extension UITapGestureRecognizer {

    func didTapAttributedTextInLabel(label: UILabel, inRange targetRange: NSRange) -> Bool {
        // Create instances of NSLayoutManager, NSTextContainer and NSTextStorage
        let layoutManager = NSLayoutManager()
        let textContainer = NSTextContainer(size: CGSize.zero)

        let mutableAttribString = NSMutableAttributedString(attributedString: label.attributedText!)
        mutableAttribString.addAttributes([NSAttributedString.Key.font: label.font!], range: NSRange(location: 0, length: label.attributedText!.length))

        let paragraphStyle = NSMutableParagraphStyle()
        paragraphStyle.lineSpacing = 6
        paragraphStyle.lineBreakMode = .byTruncatingTail
        paragraphStyle.alignment = .center
        mutableAttribString.addAttributes([.paragraphStyle: paragraphStyle], range: NSMakeRange(0, mutableAttribString.string.count))

        let textStorage = NSTextStorage(attributedString: mutableAttribString)

        // Configure textContainer
        textContainer.lineFragmentPadding = 0.0
        textContainer.lineBreakMode = label.lineBreakMode
        textContainer.maximumNumberOfLines = label.numberOfLines

        // Configure layoutManager and textStorage
        layoutManager.addTextContainer(textContainer)

        textStorage.addLayoutManager(layoutManager)

        let labelSize = label.bounds.size

        textContainer.size = labelSize

        // Find the tapped character location and compare it to the specified range
        let locationOfTouchInLabel = self.location(in: label)

        let textBoundingBox = layoutManager.usedRect(for: textContainer)
        //let textContainerOffset = CGPointMake((labelSize.width - textBoundingBox.size.width) * 0.5 - textBoundingBox.origin.x,
                                              //(labelSize.height - textBoundingBox.size.height) * 0.5 - textBoundingBox.origin.y);
        let textContainerOffset = CGPoint(x: (labelSize.width - textBoundingBox.size.width) * 0.5 - textBoundingBox.origin.x, y: (labelSize.height - textBoundingBox.size.height) * 0.5 - textBoundingBox.origin.y)

        //let locationOfTouchInTextContainer = CGPointMake(locationOfTouchInLabel.x - textContainerOffset.x,
                                                        // locationOfTouchInLabel.y - textContainerOffset.y);
        let locationOfTouchInTextContainer = CGPoint(x: locationOfTouchInLabel.x - textContainerOffset.x, y: locationOfTouchInLabel.y - textContainerOffset.y)

        let indexOfCharacter = layoutManager.characterIndex(for: locationOfTouchInTextContainer, in: textContainer, fractionOfDistanceBetweenInsertionPoints: nil)
        print("IndexOfCharacter=",indexOfCharacter)

        print("TargetRange=",targetRange)
        return NSLocationInRange(indexOfCharacter, targetRange)
    }

}

您将需要修改这个扩展为您的特定多行情况。在我的例子中,您将注意到我使用了段落样式。

let paragraphStyle = NSMutableParagraphStyle()
        paragraphStyle.lineSpacing = 6
        paragraphStyle.lineBreakMode = .byTruncatingTail
        paragraphStyle.alignment = .center
        mutableAttribString.addAttributes([.paragraphStyle: paragraphStyle], range: NSMakeRange(0, mutableAttribString.string.count))

确保在扩展中将此更改为您实际使用的行间距,以便一切计算正确。

步骤4:

添加gestureRecognizer到标签在viewDidLoad或你认为合适的地方,就像这样(只需替换< label >与你的标签名再次:

<Label>.addGestureRecognizer(UITapGestureRecognizer(target:self, action: #selector(tapLabel(gesture:))))

这是我的tapLabel函数的一个简化示例(只需将<Label>替换为您的UILabel名称):

@IBAction func tapLabel(gesture: UITapGestureRecognizer) {
        guard let text = <Label>.attributedText?.string else {
            return
        }

        let click_range = text.range(of: "(α/β)")

        if gesture.didTapAttributedTextInLabel(label: <Label>, inRange: NSRange(click_range!, in: text)) {
           print("Tapped a/b")
        }else {
           print("Tapped none")
        }
    }

在我的例子中,我的字符串是BED = N * d * [RBE + (d / (α/β))],所以我只是在这种情况下得到α/β的范围。您可以在字符串中添加“\n”以添加换行符和任何您想要的文本,并测试此以在下一行中找到字符串,它仍然会找到它并正确地检测点击!

就是这样!你完成了。享受多行可点击标签。

我们使用来自zekel的UITapGestureRecognizer类别的方便解决方案。 它使用了NSTextContainer,就像这个问题的许多答案一样。

但是,这将返回错误的字符索引。显然是因为NSTextContainer缺少关于字体样式的信息,正如这些其他帖子所指出的:

https://stackoverflow.com/a/34238382/2439941 https://stackoverflow.com/a/47358270/2439941

后改变:

NSTextStorage *textStorage = [[NSTextStorage alloc] initWithAttributedString:label.attributedText];

To:

// Apply the font of the label to the attributed text: 
NSMutableAttributedString *attributedText = [[NSMutableAttributedString alloc] initWithAttributedString:label.attributedText];
NSMutableParagraphStyle *paragraphStyle = NSMutableParagraphStyle.new;
paragraphStyle.alignment = self.label.textAlignment;
[attributedText addAttributes:@{NSFontAttributeName: label.font, NSParagraphStyleAttributeName: paragraphStyle} 
                        range:NSMakeRange(0, label.attributedText.string.length)];

// Init with attributed text from label:
NSTextStorage *textStorage = [[NSTextStorage alloc] initWithAttributedString:attributedText];

结果明显更好,点击区域现在正确地从目标字符串的第一个字符开始。但最后一个字符仍然返回NO。我们期望这与我们的目标字符串具有将字体权重设置为UIFontWeightSemibold的属性有关。而上面的代码改进应用标签。整个字符串上的字体,它有一个规则的权重。

为了解决这个问题,我们进一步改进了上面的代码片段,通过遍历所有属性范围,以支持文本中的多种字体样式:

// According to https://stackoverflow.com/a/47358270/2439941 it's required to apply the paragraph style and font of the UILabel.
// However, the attributed string might contain font formatting as well, e.g. to emphasize a word in a different font style.
// Therefor copy all attributes:
NSMutableAttributedString *attributedText = [[NSMutableAttributedString alloc] initWithAttributedString:label.attributedText];
[label.attributedText enumerateAttributesInRange:NSMakeRange(0, label.attributedText.length)
                                         options:0
                                      usingBlock:^(NSDictionary<NSAttributedStringKey,id> * _Nonnull attrs, NSRange range, BOOL * _Nonnull stop) {
    // Add each attribute:
    [attributedText addAttributes:attrs
                            range:range];
    
    // In case the attributes of this range do NOT contain a font specifier, apply the font from the UILabel:
    if (![attrs objectForKey:NSFontAttributeName]) {
        [attributedText addAttributes:@{ NSFontAttributeName : label.font }
                                range:range];
    }
}];

// Init the storage with the font attributed text:
NSTextStorage *textStorage = [[NSTextStorage alloc] initWithAttributedString:attributedText];

现在,该方法为半粗体字符串范围内的每个字符返回YES,这是预期的结果。

从iOS 15开始,SwiftUI内置支持Markdown标记语言,因此Markdown中的文本:

Text("You can [click this link](https://www.example.com) to visit the website.")

或者作为一个使用SwiftUI的最简单的例子,你可以这样做:

        HStack() {
            Text("Open the")
                .foregroundColor(.black)
            Link(destination: URL(string: "https://www.example.com/TOS.html")!) {
                Text("link")
                    .foregroundColor(.blue)
                    .underline()
            }
            Text("in browser")
                .foregroundColor(.black)
        }

翻译@samwize的扩展到Swift 4:

extension UITapGestureRecognizer {
    func didTapAttributedTextInLabel(label: UILabel, inRange targetRange: NSRange) -> Bool {
        guard let attrString = label.attributedText else {
            return false
        }

        let layoutManager = NSLayoutManager()
        let textContainer = NSTextContainer(size: .zero)
        let textStorage = NSTextStorage(attributedString: attrString)

        layoutManager.addTextContainer(textContainer)
        textStorage.addLayoutManager(layoutManager)

        textContainer.lineFragmentPadding = 0
        textContainer.lineBreakMode = label.lineBreakMode
        textContainer.maximumNumberOfLines = label.numberOfLines
        let labelSize = label.bounds.size
        textContainer.size = labelSize

        let locationOfTouchInLabel = self.location(in: label)
        let textBoundingBox = layoutManager.usedRect(for: textContainer)
        let textContainerOffset = CGPoint(x: (labelSize.width - textBoundingBox.size.width) * 0.5 - textBoundingBox.origin.x, y: (labelSize.height - textBoundingBox.size.height) * 0.5 - textBoundingBox.origin.y)
        let locationOfTouchInTextContainer = CGPoint(x: locationOfTouchInLabel.x - textContainerOffset.x, y: locationOfTouchInLabel.y - textContainerOffset.y)
        let indexOfCharacter = layoutManager.characterIndex(for: locationOfTouchInTextContainer, in: textContainer, fractionOfDistanceBetweenInsertionPoints: nil)
        return NSLocationInRange(indexOfCharacter, targetRange)
    }
}

要设置识别器(一旦你给文本和东西上色):

lblTermsOfUse.isUserInteractionEnabled = true
lblTermsOfUse.addGestureRecognizer(UITapGestureRecognizer(target: self, action: #selector(handleTapOnLabel(_:))))

...然后是手势识别器:

@objc func handleTapOnLabel(_ recognizer: UITapGestureRecognizer) {
    guard let text = lblAgreeToTerms.attributedText?.string else {
        return
    }

    if let range = text.range(of: NSLocalizedString("_onboarding_terms", comment: "terms")),
        recognizer.didTapAttributedTextInLabel(label: lblAgreeToTerms, inRange: NSRange(range, in: text)) {
        goToTermsAndConditions()
    } else if let range = text.range(of: NSLocalizedString("_onboarding_privacy", comment: "privacy")),
        recognizer.didTapAttributedTextInLabel(label: lblAgreeToTerms, inRange: NSRange(range, in: text)) {
        goToPrivacyPolicy()
    }
}

Drop-in解决方案作为UILabel上的一个类别(这假设你的UILabel使用一个带有NSLinkAttributeName属性的带属性字符串):

@implementation UILabel (Support)

- (BOOL)openTappedLinkAtLocation:(CGPoint)location {
  CGSize labelSize = self.bounds.size;

  NSTextContainer* textContainer = [[NSTextContainer alloc] initWithSize:CGSizeZero];
  textContainer.lineFragmentPadding = 0.0;
  textContainer.lineBreakMode = self.lineBreakMode;
  textContainer.maximumNumberOfLines = self.numberOfLines;
  textContainer.size = labelSize;

  NSLayoutManager* layoutManager = [[NSLayoutManager alloc] init];
  [layoutManager addTextContainer:textContainer];

  NSTextStorage* textStorage = [[NSTextStorage alloc] initWithAttributedString:self.attributedText];
  [textStorage addAttribute:NSFontAttributeName value:self.font range:NSMakeRange(0, textStorage.length)];
  [textStorage addLayoutManager:layoutManager];

  CGRect textBoundingBox = [layoutManager usedRectForTextContainer:textContainer];
  CGPoint textContainerOffset = CGPointMake((labelSize.width - textBoundingBox.size.width) * 0.5 - textBoundingBox.origin.x,
                                            (labelSize.height - textBoundingBox.size.height) * 0.5 - textBoundingBox.origin.y);
  CGPoint locationOfTouchInTextContainer = CGPointMake(location.x - textContainerOffset.x, location.y - textContainerOffset.y);
  NSInteger indexOfCharacter = [layoutManager characterIndexForPoint:locationOfTouchInTextContainer inTextContainer:textContainer fractionOfDistanceBetweenInsertionPoints:nullptr];
  if (indexOfCharacter >= 0) {
    NSURL* url = [textStorage attribute:NSLinkAttributeName atIndex:indexOfCharacter effectiveRange:nullptr];
    if (url) {
      [[UIApplication sharedApplication] openURL:url];
      return YES;
    }
  }
  return NO;
}

@end