UILongPressGestureRecognizer中断tableView滚动

Question

我创建了一个包含UILongPressGestureRecognizer的自定义Label类,我在TableViewController中的tableview单元格中调用它.长按手势识别器工作(属性sting中的两个可点击区域),但如果滚动手势在我的CustomLabel的UILongPressGestureRecognizer区域之一开始,则包含标签的tableView不再滚动(平移).我已尝试过cancelsTouchesInView = false以下各种回复,但无济于事.任何建议将不胜感激.我花了一个星期来解决这个问题.我的代码如下.

这是CustomLabel类:

class CustomLabel: UILabel {

    let layoutManager = NSLayoutManager()
    let textContainer = NSTextContainer(size: CGSize.zero)
    var textStorage = NSTextStorage() {
        didSet {
            textStorage.addLayoutManager(layoutManager)
        }
    }

    var onCharacterTapped: ((_ label: UILabel, _ characterIndex: Int, _ state: Bool) -> Void)?

    let tapGesture = UILongPressGestureRecognizer()

    override var attributedText: NSAttributedString? {
        didSet {
            if let attributedText = attributedText {

                if attributedText.string != textStorage.string {

                textStorage = NSTextStorage(attributedString: attributedText)

                DispatchQueue.main.async {

                    let characterDelay = TimeInterval(0.01 + Float(arc4random()) /  Float(UInt32.max)) / 100

                    for (index, char) in attributedText.string.characters.enumerated() {

                        DispatchQueue.main.asyncAfter(deadline: .now() + characterDelay * Double(index)) {
                            print("character ch is: \(char) at index: \(index)")
                            super.attributedText = attributedText.attributedSubstring(from: NSRange(location: 0, length: index+1))
                        }
                    }
                }
                }

            } else {
                textStorage = NSTextStorage()
            }
        }
    }

    override var lineBreakMode: NSLineBreakMode {
        didSet {
            textContainer.lineBreakMode = lineBreakMode
        }
    }

    override var numberOfLines: Int {
        didSet {
            textContainer.maximumNumberOfLines = numberOfLines
        }
    }

    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        setUp()
    }

    override init(frame: CGRect) {
        super.init(frame: frame)
        setUp()
    }

    func setUp() {
        isUserInteractionEnabled = true
        layoutManager.addTextContainer(textContainer)
        textContainer.lineFragmentPadding = 0
        textContainer.lineBreakMode = lineBreakMode
        textContainer.maximumNumberOfLines = numberOfLines
        tapGesture.addTarget(self, action: #selector(CustomLabel.labelTapped(_:)))
        tapGesture.minimumPressDuration = 0
        tapGesture.cancelsTouchesInView = false
        //tapGesture.delegate = self.superview
        addGestureRecognizer(tapGesture)
    }

    override func layoutSubviews() {
        super.layoutSubviews()
        textContainer.size = bounds.size
    }

    func labelTapped(_ gesture: UILongPressGestureRecognizer) {

        let locationOfTouch = gesture.location(in: gesture.view)
        let textBoundingBox = layoutManager.usedRect(for: textContainer)
        let textContainerOffset = CGPoint(x: (bounds.width - textBoundingBox.width) / 2 - textBoundingBox.minX, y: (bounds.height - textBoundingBox.height) / 2 - textBoundingBox.minY)
        let locationOfTouchInTextContainer = CGPoint(x: locationOfTouch.x - textContainerOffset.x, y: locationOfTouch.y - textContainerOffset.y)
        let indexOfCharacter = layoutManager.characterIndex(for: locationOfTouchInTextContainer, in: textContainer, fractionOfDistanceBetweenInsertionPoints: nil)

        if gesture.state == .began {

            onCharacterTapped?(self, indexOfCharacter, true)

        } else if gesture.state == .ended {

            onCharacterTapped?(self, indexOfCharacter, false)

        }

    }

}

这是cellClass:

class friendTextCell: UITableViewCell {

    @IBOutlet weak var labelText: CustomLabel!

    override func awakeFromNib() {
        super.awakeFromNib()
        self.layoutIfNeeded()
    }

}

以下是从创建CustomCells的TableViewControllerClass中选择的内容:

class UsersViewController: UITableViewController, UIGestureRecognizerDelegate {

private func gestureRecognizer(gestureRecognizer: UIPanGestureRecognizer, shouldRecognizeSimultaneouslyWithGestureRecognizer otherGestureRecognizer: UILongPressGestureRecognizer) -> Bool {return true}


    func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldRequireFailureOf otherGestureRecognizer: UIGestureRecognizer) -> Bool {
        return gestureRecognizer === longPressRecognizer &&
            (otherGestureRecognizer.view?.isDescendant(of:tableView) ?? false)
    }

override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "friendText", for: indexPath) as! friendTextCell

        print("keyArrrrray is: \(keyArray)")

        if indexPath.section == 0 && indexPath.row < keyArray.count {
            self.removeInstructions()
            cell.labelText.font = cell.labelText.font.withSize(17)
            let text = "> "+namesArray[indexPath.row] + ": " + linkArray[indexPath.row]
            let name = namesArray[indexPath.row]
            let link = linkArray[indexPath.row]
            let imageLink = imageURLArray[indexPath.row]
            let nameChCount = name.characters.count
            let linkChCount = link.characters.count

            let attributedString = NSMutableAttributedString(string: name + ": " + link, attributes: nil)

            let totalChCount = attributedString.string.characters.count

            let linkRange = NSMakeRange(0, nameChCount) // for the word "link" in the string above

            let linkAttributes: [String : AnyObject] = [
                NSForegroundColorAttributeName : UIColor.white, NSUnderlineStyleAttributeName : NSUnderlineStyle.styleSingle.rawValue as AnyObject]
            attributedString.setAttributes(linkAttributes, range:linkRange)

            cell.labelText.attributedText = attributedString

            cell.labelText.onCharacterTapped = { label, characterIndex, state in

                let highlight: [String : AnyObject] = [NSForegroundColorAttributeName : UIColor.black, NSBackgroundColorAttributeName : UIColor.white]

                if state == true {
                    if characterIndex < nameChCount {
                        print("name press began at character \(characterIndex)")
                        attributedString.addAttributes(highlight, range:NSMakeRange(0, nameChCount))
                        cell.labelText.attributedText = attributedString
                    } else if characterIndex > nameChCount {
                        print("link press began at character \(characterIndex)")
                        let startPos = nameChCount + 2
                        let endPos = totalChCount-nameChCount-2
                        attributedString.addAttributes(highlight, range:NSMakeRange(startPos, endPos))
                        cell.labelText.attributedText = attributedString
                    }

                } else if state == false {

                    if characterIndex < name.characters.count {

                        if let userVC:UserViewTableViewController = self.storyboard?.instantiateViewController(withIdentifier: "UserVC") as? UserViewTableViewController {
                            userVC.userName = name
                            userVC.shareLink = link
                            userVC.imageLink = imageLink
                            self.navigationController?.pushViewController(userVC, animated: true)
                        }

                }

                if characterIndex > name.characters.count && characterIndex <= link.characters.count + name.characters.count {

                    //extract link from array
                    let link = self.linkArray[indexPath.row]
                    print("on click link is: \(link)")

                    //Present SafariViewController with link
                    let svc = SFSafariViewController(url: NSURL(string: link)! as URL)
                    self.present(svc, animated: true, completion: nil)

                }
                }

            }

        } else if keyArray.isEmpty && indexPath.section == 0 {

            cell.labelText.text = "..."

        }

        if indexPath.section == 1 && keyArray.count <= 1 {
            let message = "> Press the + button to add more friends."
            cell.labelText.animate(newText: message, characterDelay: TimeInterval(0.01 + Float(arc4random()) /  Float(UInt32.max)) / 200)
        } else if indexPath.section == 1 {
            cell.labelText.text = ""
        }

        return cell

    }

Answer 1

如果滚动手势从 UILongPressGestureRecognizer 之一开始，则包含标签的 tableView 不再滚动（平移）

当您将 UILongPressGestureRecognizer 的最小按下持续时间设置为 0 并且它开始抓取滚动视图的嵌入式手势识别器时，就会出现此问题。您可以通过使用更大的延迟来解决它，如果您需要使用带有延迟的长按手势识别器，它应该是怎样的。首先将响应您的表格视图didSelectRow at，然后延迟您的选择器。它对我有用，尽管我在声明识别器的选择器方法之前删除tapGesture.cancelsTouchesInView = false并添加了属性（如果您用 swift 4 编写则需要）。@objc

UILongPressGestureRecognizer如果您想立即使用，只需使用UITapGestureRecognizer. didSelectRow在这种情况下，表视图将滚动，但如果点击标签，则无法接收方法。表和集合视图手势委托被设置为底层滚动视图，因此您无法为此目的使用UIGestureRecognizerDelegate方法。UIViewController如果您想在识别器触发时在视图控制器中接收某种回调，您可以通过实现委托方法来抛出回调。

例如，创建CustomLabel实现函数的委托。labelTapped在您的选择器中调用该委托函数。让您的单元格符合该委托，并在您的单元格中重复该操作以将函数抛出到您的UIViewController. 您也可以使用闭包委托模式。

希望有帮助。

更新

因此，解决方案是像您最初那样将UILongPressGestureRecognizers设置minimumPressDuration为 0 并将委托分配给它的单元格（在我的例子中为超级视图）。在单元格中，您需要重写此方法：

gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWith otherGestureRecognizer: UIGestureRecognizer) -> Bool {
    return gestureRecognizer == yourGesture || otherGestureRecognizer == yourGesture
}

顺便说一下，你不需要让你的细胞UIGestureRecognizerDelegate像它已经做的那样