ios - 点击 UILabel 的一部分文本

Question

我有一个问题，boundingRectForGlyphRange 总是返回 CGRect.zero“0.0, 0.0, 0.0, 0.0”。

例如，我正在编码以触摸 UILabel 功能的一部分文本。我的文本第一部分是任何文本，第二部分是阅读更多。

我希望点击识别器仅在我触摸阅读更多时工作。如果我触及 UILabel 上的任何一点，CGRectContainsPoint 总是返回 true，然后调用操作。

这是我的代码:

override func viewDidLoad() {
        super.viewDidLoad()
        
        // The full string
        
        let firstPart:NSMutableAttributedString = NSMutableAttributedString(string: "Lorem ipsum dolor set amit ", attributes: [NSFontAttributeName: UIFont.systemFontOfSize(13)])
        firstPart.addAttribute(NSForegroundColorAttributeName, value: UIColor.blackColor(),
            range: NSRange(location: 0, length: firstPart.length))
        info.appendAttributedString(firstPart)
        
        // The "Read More" string that should be touchable
        let secondPart:NSMutableAttributedString = NSMutableAttributedString(string: "READ MORE", attributes: [NSFontAttributeName: UIFont.systemFontOfSize(14)])
        secondPart.addAttribute(NSForegroundColorAttributeName, value: UIColor.blackColor(),
            range: NSRange(location: 0, length: secondPart.length))
        info.appendAttributedString(secondPart)
        
        lblTest.attributedText = info
        
        // Store range of chars we want to detect touches for
        moreStringRange = NSMakeRange(firstPart.length, secondPart.length)
        print("moreStringRange\(moreStringRange)")
        
        tapRec.addTarget(self, action: "didTap:")
        lblTest.addGestureRecognizer(tapRec)
        
    }


    func didTap(sender:AnyObject) {
        // Storage class stores the string, obviously
        let textStorage:NSTextStorage = NSTextStorage(attributedString: info)
        // The storage class owns a layout manager
        let layoutManager:NSLayoutManager = NSLayoutManager()
        textStorage.addLayoutManager(layoutManager)
        
        // Layout manager owns a container which basically
        // defines the bounds the text should be contained in
        let textContainer:NSTextContainer = NSTextContainer(size: lblTest.frame.size)
        textContainer.lineFragmentPadding = 0
        textContainer.lineBreakMode = lblTest.lineBreakMode
        
        // Begin computation of actual frame
        // Glyph is the final display representation
        var glyphRange = NSRange()
        // Extract the glyph range
        layoutManager.characterRangeForGlyphRange(moreStringRange!, actualGlyphRange: &glyphRange)
        
        // Compute the rect of glyph in the text container
        print("glyphRange\(glyphRange)")
        print("textContainer\(textContainer)")
        let glyphRect:CGRect = layoutManager.boundingRectForGlyphRange(glyphRange, inTextContainer: textContainer)
        
        // Final rect relative to the textLabel.
        print("\(glyphRect)")
        
        // Now figure out if the touch point is inside our rect
        let touchPoint:CGPoint = tapRec.locationOfTouch(0, inView: lblTest)
        
        if CGRectContainsPoint(glyphRect, touchPoint) {
            print("User tapped on Read More. So show something more")
        }
    }
}

Answer 1

# swift 4.2请在此处找到解决方案，以获取 Label 的特定文本 action。

1. 标签声明

   @IBOutlet weak var lblTerms: UILabel!
   

2. 为标签设置属性文本

   let text = "Please agree for Terms & Conditions."
   lblTerms.text = text
   self.lblTerms.textColor =  UIColor.white
   let underlineAttriString = NSMutableAttributedString(string: text)
   let range1 = (text as NSString).range(of: "Terms & Conditions.")
        underlineAttriString.addAttribute(NSAttributedString.Key.underlineStyle, value: NSUnderlineStyle.single.rawValue, range: range1)
        underlineAttriString.addAttribute(NSAttributedString.Key.font, value: UIFont.init(name: Theme.Font.Regular, size: Theme.Font.size.lblSize)!, range: range1)
        underlineAttriString.addAttribute(NSAttributedString.Key.foregroundColor, value: Theme.color.primaryGreen, range: range1)
   lblTerms.attributedText = underlineAttriString
   lblTerms.isUserInteractionEnabled = true
   lblTerms.addGestureRecognizer(UITapGestureRecognizer(target:self, action: #selector(tapLabel(gesture:))))
   

看起来像上图。

1. 将tapLabel 操作方法添加到 Controller

   @IBAction func tapLabel(gesture: UITapGestureRecognizer) {
   let termsRange = (text as NSString).range(of: "Terms & Conditions")
   // comment for now
   //let privacyRange = (text as NSString).range(of: "Privacy Policy")
   
   if gesture.didTapAttributedTextInLabel(label: lblTerms, inRange: termsRange) {
       print("Tapped terms")
   } else if gesture.didTapAttributedTextInLabel(label: lblTerms, inRange: privacyRange) {
       print("Tapped privacy") 
   } else {                
       print("Tapped none")
   }
   }
   

2. 添加 UITapGestureRecognizer 扩展

   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 textStorage = NSTextStorage(attributedString: label.attributedText!)
   
           // Configure layoutManager and textStorage
           layoutManager.addTextContainer(textContainer)
           textStorage.addLayoutManager(layoutManager)
   
           // Configure textContainer
           textContainer.lineFragmentPadding = 0.0
           textContainer.lineBreakMode = label.lineBreakMode
           textContainer.maximumNumberOfLines = label.numberOfLines
           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)
           return NSLocationInRange(indexOfCharacter, targetRange)
       }
   }
   

确保做到:

lblTerms.isUserInteractionEnabled = true