Hinzufügen "...Mehr Lesen" am Ende des UILabel

Swift4 (IOS 11.2)

Readmore am Ende des Etiketts ohne Aktion

extension UILabel {

    func addTrailing(with trailingText: String, moreText: String, moreTextFont: UIFont, moreTextColor: UIColor) {
        let readMoreText: String = trailingText + moreText

        let lengthForVisibleString: Int = self.visibleTextLength
        let mutableString: String = self.text!
        let trimmedString: String? = (mutableString as NSString).replacingCharacters(in: NSRange(location: lengthForVisibleString, length: ((self.text?.count)! - lengthForVisibleString)), with: "")
        let readMoreLength: Int = (readMoreText.count)
        let trimmedForReadMore: String = (trimmedString! as NSString).replacingCharacters(in: NSRange(location: ((trimmedString?.count ?? 0) - readMoreLength), length: readMoreLength), with: "") + trailingText
        let answerAttributed = NSMutableAttributedString(string: trimmedForReadMore, attributes: [NSAttributedStringKey.font: self.font])
        let readMoreAttributed = NSMutableAttributedString(string: moreText, attributes: [NSAttributedStringKey.font: moreTextFont, NSAttributedStringKey.foregroundColor: moreTextColor])
        answerAttributed.append(readMoreAttributed)
        self.attributedText = answerAttributed
    }

    var visibleTextLength: Int {
        let font: UIFont = self.font
        let mode: NSLineBreakMode = self.lineBreakMode
        let labelWidth: CGFloat = self.frame.size.width
        let labelHeight: CGFloat = self.frame.size.height
        let sizeConstraint = CGSize(width: labelWidth, height: CGFloat.greatestFiniteMagnitude)

        let attributes: [AnyHashable: Any] = [NSAttributedStringKey.font: font]
        let attributedText = NSAttributedString(string: self.text!, attributes: attributes as? [NSAttributedStringKey : Any])
        let boundingRect: CGRect = attributedText.boundingRect(with: sizeConstraint, options: .usesLineFragmentOrigin, context: nil)

        if boundingRect.size.height > labelHeight {
            var index: Int = 0
            var prev: Int = 0
            let characterSet = CharacterSet.whitespacesAndNewlines
            repeat {
                prev = index
                if mode == NSLineBreakMode.byCharWrapping {
                    index += 1
                } else {
                    index = (self.text! as NSString).rangeOfCharacter(from: characterSet, options: [], range: NSRange(location: index + 1, length: self.text!.count - index - 1)).location
                }
            } while index != NSNotFound && index < self.text!.count && (self.text! as NSString).substring(to: index).boundingRect(with: sizeConstraint, options: .usesLineFragmentOrigin, attributes: attributes as? [NSAttributedStringKey : Any], context: nil).size.height <= labelHeight
            return prev
        }
        return self.text!.count
    }
}

Swift 4.2

extension UILabel {

        func addTrailing(with trailingText: String, moreText: String, moreTextFont: UIFont, moreTextColor: UIColor) {
            let readMoreText: String = trailingText + moreText

            let lengthForVisibleString: Int = self.vissibleTextLength
            let mutableString: String = self.text!
            let trimmedString: String? = (mutableString as NSString).replacingCharacters(in: NSRange(location: lengthForVisibleString, length: ((self.text?.count)! - lengthForVisibleString)), with: "")
            let readMoreLength: Int = (readMoreText.count)
            let trimmedForReadMore: String = (trimmedString! as NSString).replacingCharacters(in: NSRange(location: ((trimmedString?.count ?? 0) - readMoreLength), length: readMoreLength), with: "") + trailingText
            let answerAttributed = NSMutableAttributedString(string: trimmedForReadMore, attributes: [NSAttributedString.Key.font: self.font])
            let readMoreAttributed = NSMutableAttributedString(string: moreText, attributes: [NSAttributedString.Key.font: moreTextFont, NSAttributedString.Key.foregroundColor: moreTextColor])
            answerAttributed.append(readMoreAttributed)
            self.attributedText = answerAttributed
        }

        var vissibleTextLength: Int {
            let font: UIFont = self.font
            let mode: NSLineBreakMode = self.lineBreakMode
            let labelWidth: CGFloat = self.frame.size.width
            let labelHeight: CGFloat = self.frame.size.height
            let sizeConstraint = CGSize(width: labelWidth, height: CGFloat.greatestFiniteMagnitude)

            let attributes: [AnyHashable: Any] = [NSAttributedString.Key.font: font]
            let attributedText = NSAttributedString(string: self.text!, attributes: attributes as? [NSAttributedString.Key : Any])
            let boundingRect: CGRect = attributedText.boundingRect(with: sizeConstraint, options: .usesLineFragmentOrigin, context: nil)

            if boundingRect.size.height > labelHeight {
                var index: Int = 0
                var prev: Int = 0
                let characterSet = CharacterSet.whitespacesAndNewlines
                repeat {
                    prev = index
                    if mode == NSLineBreakMode.byCharWrapping {
                        index += 1
                    } else {
                        index = (self.text! as NSString).rangeOfCharacter(from: characterSet, options: [], range: NSRange(location: index + 1, length: self.text!.count - index - 1)).location
                    }
                } while index != NSNotFound && index < self.text!.count && (self.text! as NSString).substring(to: index).boundingRect(with: sizeConstraint, options: .usesLineFragmentOrigin, attributes: attributes as? [NSAttributedString.Key : Any], context: nil).size.height <= labelHeight
                return prev
            }
            return self.text!.count
        }
    }

Nutzung

let readmoreFont = UIFont(name: "Helvetica-Oblique", size: 11.0)
let readmoreFontColor = UIColor.blue
DispatchQueue.main.async {
    self.yourLabel.addTrailing(with: "... ", moreText: "Readmore", moreTextFont: readmoreFont!, moreTextColor: readmoreFontColor)
}

Ergebnis

HINWEIS: - die Aktion ist nicht im Lieferumfang enthalten für Readmore

Tttattributed label hat diese Funktion

https://github.com/TTTAttributedLabel/TTTAttributedLabel

Müssen Sie das "abschneiden" token wie
"Lesen Sie mehr..."

Sehen

attributedTruncationToken

var subTitleLabel = TTTAttributedLabel(frame : frame)
    self.addSubview(subTitleLabel)
    var trunc = NSMutableAttributedString(string: "...more")
    trunc.addAttribute(NSFontAttributeName, value: UIFont.systemFontOfSize(12), range: NSMakeRange(0, 7))
    trunc.addAttribute(NSForegroundColorAttributeName, value: UIColor.blueColor(), range: NSMakeRange(0, 7))
    subTitleLabel.attributedTruncationToken = trunc
    subTitleLabel.numberOfLines = 1
    subTitleLabel.autoresizingMask = UIViewAutoresizing.FlexibleHeight | UIViewAutoresizing.FlexibleWidth

Meine Lösung ist, ich erstelle ein UIButton (name mehr Lesen) unten-rechts und unten die UILabel.
Danach überprüfe ich die UILabel ist abgeschnitten oder nicht-oder ausblenden der UIButton

CGSize sizeOfText = [self.label.text boundingRectWithSize: CGSizeMake(self.label.intrinsicContentSize.width, CGFLOAT_MAX)
                                                 options: (NSStringDrawingUsesLineFragmentOrigin|NSStringDrawingUsesFontLeading)
                                              attributes: [NSDictionary dictionaryWithObject:self.label.font forKey:NSFontAttributeName] context: nil].size;

if (self.label.intrinsicContentSize.height < ceilf(sizeOfText.height)) {
    //label is truncated
    self.readmoreButton.hidden = NO; //show Read more button
}else{
    self.readmoreButton.hidden = YES;
}

=== Swift 3-version

let textheight = self.label.text?.height(withConstrainedWidth: self.label.frame.width, font: self.label.font)
    if self.label.intrinsicContentSize.height < textheight! {
        self.readmoreButton.isHidden = false
    }else{
        self.readmoreButton.isHidden = true
    }

diese Erweiterung hinzufügen:

extension String {

func height(withConstrainedWidth width: CGFloat, font: UIFont) -> CGFloat {
    let constraintRect = CGSize(width: width, height: .greatestFiniteMagnitude)
    let boundingBox = self.boundingRect(with: constraintRect, options: .usesLineFragmentOrigin, attributes: [NSFontAttributeName: font], context: nil)

    return boundingBox.height
}

}

Hoffe, dass dies helfen

Unter Verwendung der Methode - boundingRectWithSize:Optionen:Attribute:context: und Weitergabe Ihrer Schrift als NSFontAttributeName Schlüssel für NSAttributedString geben Sie die richtige rect benötigt.

Aus, die Sie brauchen, um zu überprüfen, ob es größer als Ihre label-Grenzen minus offset. Nur wenn ja, müssen Sie schneiden Sie Ihre text und Karte Read More am Ende.

func updateData(_ label: UILabel) {
    self.headerLabel.text = detailViewModel.firstTitle
    self.detailLabel.text = detailViewModel.firstContent

    headerTitle = detailViewModel.firstTitle
    detailTitle = detailViewModel.firstContent

    DispatchQueue.main.async {
        let readMoreText = "...View More"
        let stringColor: UIColor = UIColor.blue
        let attributes = [NSForegroundColorAttributeName: stringColor]

        let numberOfLines = self.detailLabel.numberOfVisibleLines

        if numberOfLines > 2 {

            let lengthForVisibleString: Int = self.fit( self.detailLabel.text, into: self.detailLabel)
            let mutableString = self.detailLabel.text ?? ""
            let trimmedString = (mutableString as NSString).replacingCharacters(in: NSRange(location: lengthForVisibleString, length: (self.detailLabel?.text?.count ?? 0) - lengthForVisibleString), with: "")
            let readMoreLength: Int = readMoreText.count
            let trimmedForReadMore = (trimmedString as NSString).replacingCharacters(in: NSRange(location: trimmedString.count - readMoreLength, length: readMoreLength), with: "")
            let answerAttributed = NSMutableAttributedString(string: trimmedForReadMore, attributes: [NSFontAttributeName: self.detailLabel.font])

            let readMoreAttributed = NSMutableAttributedString(string: readMoreText, attributes: attributes)
            answerAttributed.append(readMoreAttributed)
            self.detailLabel.attributedText = answerAttributed


            let readMoreGesture = UITapGestureRecognizer(target: self, action:#selector(FundDetailsTableViewCell.showViewMore(_:)))
            readMoreGesture.numberOfTapsRequired = 1
            self.detailLabel.addGestureRecognizer(readMoreGesture)
            self.detailLabel.isUserInteractionEnabled = true
        }
    }
}

func fit(_ string: String?, into label: UILabel?) -> Int {
    guard let stringObjc = string as NSString? else {
        return 0
    }
    let font: UIFont = label?.font ?? UIFont.systemFont(ofSize: 14.0)
    let mode: NSLineBreakMode? = label?.lineBreakMode
    let labelWidth: CGFloat? = label?.frame.size.width
    let labelHeight: CGFloat? = label?.frame.size.height
    let sizeConstraint = CGSize(width: labelWidth ?? 0.0, height: CGFloat.greatestFiniteMagnitude)
    let attributes = [NSFontAttributeName: font]

    let device = UIDevice.current
    let iosVersion = Double(device.systemVersion) ?? 0

    if iosVersion > 7 {
        let attributedText = NSAttributedString(string: string ?? "", attributes: attributes)
        let boundingRect: CGRect = attributedText.boundingRect(with: sizeConstraint, options: .usesLineFragmentOrigin, context: nil)
        do {
            if boundingRect.size.height > (labelHeight ?? 0.0) {
                var index: Int = 0
                var prev: Int
                let characterSet = CharacterSet.whitespacesAndNewlines
                repeat {
                    prev = index
                    if mode == .byCharWrapping {
                        index += 1
                    } else {
                        index = Int((string as NSString?)?.rangeOfCharacter(from: characterSet, options: [], range: NSRange(location: index + 1, length: (string?.count ?? 0) - index - 1)).location ?? 0)
                    }
                } while index != NSNotFound && index < (string?.count ?? 0)
                    && (stringObjc.substring(to: index).boundingRect(with: sizeConstraint, options: .usesLineFragmentOrigin, attributes: attributes, context: nil).size.height) <= labelHeight!
                return prev;
            }
        }
    } else {
        if stringObjc.size(attributes: attributes).height > labelHeight! {
            var index: Int = 0
            var prev: Int
            let characterSet = CharacterSet.whitespacesAndNewlines
            repeat {
                prev = index
                if mode == .byCharWrapping {
                    index += 1
                } else {
                    index = stringObjc.rangeOfCharacter(from: characterSet, options: NSString.CompareOptions.caseInsensitive, range: NSRange(location: index + 1, length: stringObjc.length - index - 1)).location
                }

            } while index != NSNotFound && index < (string?.count)! && (stringObjc.substring(to: index) as NSString).size(attributes: attributes).height <= labelHeight!
            return prev

        }
    }
    return (string?.count)!
}

func showViewMore(_ sender: UITapGestureRecognizer) {

}

extension UILabel {
    var numberOfVisibleLines: Int {
        let textSize = CGSize(width: CGFloat(self.frame.size.width), height: CGFloat(MAXFLOAT))
        let rHeight: Int = lroundf(Float(self.sizeThatFits(textSize).height))
        let charSize: Int = lroundf(Float(self.font.pointSize))
        return rHeight / charSize
    }
}

Wissen Sie, es gibt keine touch-Aktion von UILabel. so you cant touch '...Mehr Lesen' wenn der ganze text in einem UILabel.

Hinweis: meine Lösung ist, fügen Sie einen hintergrund entfernen-Taste Ende der UILabel.