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

有些答案并不如我所料。这是Swift解决方案,也支持textAlignment和多行。不需要子类化,只是这个UITapGestureRecognizer扩展:

import UIKit


extension UITapGestureRecognizer {
    
    func didTapAttributedString(_ string: String, in label: UILabel) -> Bool {
        
        guard let text = label.text else {
            
            return false
        }
        
        let range = (text as NSString).range(of: string)
        return self.didTapAttributedText(label: label, inRange: range)
    }
    
    private func didTapAttributedText(label: UILabel, inRange targetRange: NSRange) -> Bool {
        
        guard let attributedText = label.attributedText else {
            
            assertionFailure("attributedText must be set")
            return false
        }
        
        let textContainer = createTextContainer(for: label)
        
        let layoutManager = NSLayoutManager()
        layoutManager.addTextContainer(textContainer)
        
        let textStorage = NSTextStorage(attributedString: attributedText)
        if let font = label.font {
            
            textStorage.addAttribute(NSAttributedString.Key.font, value: font, range: NSMakeRange(0, attributedText.length))
        }
        textStorage.addLayoutManager(layoutManager)
        
        let locationOfTouchInLabel = location(in: label)
        let textBoundingBox = layoutManager.usedRect(for: textContainer)
        let alignmentOffset = aligmentOffset(for: label)
        
        let xOffset = ((label.bounds.size.width - textBoundingBox.size.width) * alignmentOffset) - textBoundingBox.origin.x
        let yOffset = ((label.bounds.size.height - textBoundingBox.size.height) * alignmentOffset) - textBoundingBox.origin.y
        let locationOfTouchInTextContainer = CGPoint(x: locationOfTouchInLabel.x - xOffset, y: locationOfTouchInLabel.y - yOffset)
        
        let characterTapped = layoutManager.characterIndex(for: locationOfTouchInTextContainer, in: textContainer, fractionOfDistanceBetweenInsertionPoints: nil)
        
        let lineTapped = Int(ceil(locationOfTouchInLabel.y / label.font.lineHeight)) - 1
        let rightMostPointInLineTapped = CGPoint(x: label.bounds.size.width, y: label.font.lineHeight * CGFloat(lineTapped))
        let charsInLineTapped = layoutManager.characterIndex(for: rightMostPointInLineTapped, in: textContainer, fractionOfDistanceBetweenInsertionPoints: nil)
        
        return characterTapped < charsInLineTapped ? targetRange.contains(characterTapped) : false
    }
    
    private func createTextContainer(for label: UILabel) -> NSTextContainer {
        
        let textContainer = NSTextContainer(size: label.bounds.size)
        textContainer.lineFragmentPadding = 0.0
        textContainer.lineBreakMode = label.lineBreakMode
        textContainer.maximumNumberOfLines = label.numberOfLines
        return textContainer
    }
    
    private func aligmentOffset(for label: UILabel) -> CGFloat {
        
        switch label.textAlignment {
            
        case .left, .natural, .justified:
            
            return 0.0
        case .center:
            
            return 0.5
        case .right:
            
            return 1.0
            
            @unknown default:
            
            return 0.0
        }
    }
}

用法:

class ViewController: UIViewController {
    
    @IBOutlet var label : UILabel!
    
    let selectableString1 = "consectetur"
    let selectableString2 = "cupidatat"
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        let text = "Lorem ipsum dolor sit amet, \(selectableString1) adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat \(selectableString2) non proident, sunt in culpa qui officia deserunt mollit anim id est laborum."
        label.attributedText = NSMutableAttributedString(attributedString: NSAttributedString(string: text))
        
        let tapGesture = UITapGestureRecognizer(target: self, action: #selector(labelTapped))
        label.addGestureRecognizer(tapGesture)
        label.isUserInteractionEnabled = true
    }
    
    @objc func labelTapped(gesture: UITapGestureRecognizer) {
        
        if gesture.didTapAttributedString(selectableString1, in: label) {
            
            print("\(selectableString1) tapped")
        } else if gesture.didTapAttributedString(selectableString2, in: label) {
            
            print("\(selectableString2) tapped")
        } else {
            
            print("Text tapped")
        }
    }
}

其他回答

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()
    }
}

我创建了一个名为ResponsiveLabel的UILabel子类,它是基于ios7中引入的textkit API。它使用了NAlexN建议的相同方法。它提供了在文本中指定搜索模式的灵活性。可以指定应用于这些模式的样式,以及在敲击模式时要执行的操作。

//Detects email in text

 NSString *emailRegexString = @"[A-Z0-9._%+-]+@[A-Z0-9.-]+\\.[A-Z]{2,4}";
 NSError *error;
 NSRegularExpression *regex = [[NSRegularExpression alloc]initWithPattern:emailRegexString options:0 error:&error];
 PatternDescriptor *descriptor = [[PatternDescriptor alloc]initWithRegex:regex withSearchType:PatternSearchTypeAll withPatternAttributes:@{NSForegroundColorAttributeName:[UIColor redColor]}];
 [self.customLabel enablePatternDetection:descriptor];

如果你想让一个字符串可点击,你可以这样做。这段代码将属性应用到字符串“text”的每个出现处。

PatternTapResponder tapResponder = ^(NSString *string) {
    NSLog(@"tapped = %@",string);
};

[self.customLabel enableStringDetection:@"text" withAttributes:@{NSForegroundColorAttributeName:[UIColor redColor],
                                                                 RLTapResponderAttributeName: tapResponder}];

UITextView支持OS3.0中的数据检测器,而UILabel不支持。

如果你在UITextView上启用了数据检测器,并且你的文本包含url、电话号码等,它们将以链接的形式出现。

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。

老问题,但如果任何人都可以使用UITextView而不是UILabel,那就很容易了。标准网址,电话号码等将自动检测(并可点击)。

然而,如果你需要自定义检测,也就是说,如果你想在用户点击一个特定的单词后能够调用任何自定义方法,你需要使用NSAttributedStrings和一个NSLinkAttributeName属性,它将指向一个自定义URL方案(而不是在默认情况下使用http URL方案)。雷·温德里奇在这里报道

引用上述链接中的代码:

NSMutableAttributedString *attributedString = [[NSMutableAttributedString alloc] initWithString:@"This is an example by @marcelofabri_"];
[attributedString addAttribute:NSLinkAttributeName
                     value:@"username://marcelofabri_"
                     range:[[attributedString string] rangeOfString:@"@marcelofabri_"]];

NSDictionary *linkAttributes = @{NSForegroundColorAttributeName: [UIColor greenColor],
                             NSUnderlineColorAttributeName: [UIColor lightGrayColor],
                             NSUnderlineStyleAttributeName: @(NSUnderlinePatternSolid)};

// assume that textView is a UITextView previously created (either by code or Interface Builder)
textView.linkTextAttributes = linkAttributes; // customizes the appearance of links
textView.attributedText = attributedString;
textView.delegate = self;

要检测这些链接点击,实现这个:

- (BOOL)textView:(UITextView *)textView shouldInteractWithURL:(NSURL *)URL inRange:(NSRange)characterRange {
    if ([[URL scheme] isEqualToString:@"username"]) {
        NSString *username = [URL host]; 
        // do something with this username
        // ...
        return NO;
    }
    return YES; // let the system open this URL
}

PS:确保你的UITextView是可选的。