Question

我的应用程序中有一个图像轮播，我使用UIScrollView来显示其中的图像。一切正常，只是我想知道如何阻止UIScrollView中的运动

我正在尝试通过以下方式阻止垂直滚动：

scrollView.showsVerticalScrollIndicator = false
scrollView.contentSize  = CGSize(width: scrollView.contentSize.width, height: 0) //disable vertical

所有内容都能正常工作，并且确实会阻止垂直滚动

问题是，我也有一个计时器，可以通过以下方式以编程方式移动UIScrollView：

var frame: CGRect = scrollView.frame
frame.origin.x = frame.size.width * CGFloat(pageToMove)
frame.origin.y = -35
scrollView.scrollRectToVisible(frame, animated: true)

一旦我阻止了垂直滚动， scrollReactToVisible的此功能不执行任何操作。我对此没有任何错误。

目前是否有一种方法可以同时垂直阻止滚动（并允许像往常一样向左和向左滚动）并以编程方式移动滚动视图？

我要附加我的全视图控制器：

class CaruselleScreenViewController: UIViewController, CaruselleScreenViewProtocol, UIScrollViewDelegate {

    var myPresenter: CaruselleScreenPresenterProtocol?

    @IBOutlet weak var pageControl: UIPageControl!
    @IBOutlet weak var scrollView: UIScrollView!

    var slides:[CaruselleTipsCard] = [];

    var timer:Timer?
    var currentPageMultiplayer = 0

    override func viewDidLoad() {
        super.viewDidLoad()

        myPresenter = CaruselleScreenPresenter(controller: self)

        //initlizes view
        pageControl.numberOfPages = slides.count
        pageControl.currentPage = 0
        view.bringSubview(toFront: pageControl)

        //delegates
        scrollView.delegate = self

        ////blocks vertical movement
        scrollView.showsVerticalScrollIndicator = false
        //scrollView.contentSize  = CGSize(width: scrollView.contentSize.width, height: 0) //disable vertical
    }

    func scheduleTimer(_ timeInterval: TimeInterval){
        timer = Timer.scheduledTimer(timeInterval: timeInterval, target: self, selector: #selector(timerCall), userInfo: nil, repeats: false)
    }

    @objc func timerCall(){
        print("Timer executed")

        currentPageMultiplayer = currentPageMultiplayer + 1

        if (currentPageMultiplayer == 5) {
            currentPageMultiplayer = 0
        }
        pageControl.currentPage = currentPageMultiplayer
        scrollToPage(pageToMove: currentPageMultiplayer)

        scheduleTimer(5)
    }

    func scrollToPage(pageToMove: Int) {
        print ("new one")
        var frame: CGRect = scrollView.frame
        frame.origin.x = frame.size.width * CGFloat(pageToMove)
        frame.origin.y = -35
        scrollView.scrollRectToVisible(frame, animated: true)
    }

    func createSlides() -> [CaruselleTipsCard] {

        let slide1:CaruselleTipsCard = Bundle.main.loadNibNamed("CaruselleTipsCard", owner: self, options: nil)?.first as! CaruselleTipsCard
        slide1.mainPic.image = UIImage(named: "backlightingIllo")

        //
        let slide2:CaruselleTipsCard = Bundle.main.loadNibNamed("CaruselleTipsCard", owner: self, options: nil)?.first as! CaruselleTipsCard
        slide2.mainPic.image = UIImage(named: "comfortableIllo")

        //
        let slide3:CaruselleTipsCard = Bundle.main.loadNibNamed("CaruselleTipsCard", owner: self, options: nil)?.first as! CaruselleTipsCard
        slide3.mainPic.image = UIImage(named: "pharmacyIllo")

        //
        let slide4:CaruselleTipsCard = Bundle.main.loadNibNamed("CaruselleTipsCard", owner: self, options: nil)?.first as! CaruselleTipsCard
        slide4.mainPic.image = UIImage(named: "batteryIllo")

        //
        let slide5:CaruselleTipsCard = Bundle.main.loadNibNamed("CaruselleTipsCard", owner: self, options: nil)?.first as! CaruselleTipsCard
        slide5.mainPic.image = UIImage(named: "wiFiIllo")

        return [slide1, slide2, slide3, slide4, slide5]
    }

    func setupSlideScrollView(slides : [CaruselleTipsCard]) {
        scrollView.frame = CGRect(x: 0, y: 0, width: view.frame.width, height: view.frame.height)
        scrollView.contentSize = CGSize(width: view.frame.width * CGFloat(slides.count), height: view.frame.height)
        scrollView.isPagingEnabled = true

        for i in 0 ..< slides.count {
            slides[i].frame = CGRect(x: view.frame.width * CGFloat(i), y: 0, width: view.frame.width, height: view.frame.height)
            scrollView.addSubview(slides[i])
        }
    }


    //////

    /*
     * default function called when view is scrolled. In order to enable callback
     * when scrollview is scrolled, the below code needs to be called:
     * slideScrollView.delegate = self or
     */
    func scrollViewDidScroll(_ scrollView: UIScrollView) {
        let pageIndex = round(scrollView.contentOffset.x/view.frame.width)
        pageControl.currentPage = Int(pageIndex)

        let maximumHorizontalOffset: CGFloat = scrollView.contentSize.width - scrollView.frame.width
        let currentHorizontalOffset: CGFloat = scrollView.contentOffset.x

        // vertical
        let maximumVerticalOffset: CGFloat = scrollView.contentSize.height - scrollView.frame.height
        let currentVerticalOffset: CGFloat = scrollView.contentOffset.y

        let percentageHorizontalOffset: CGFloat = currentHorizontalOffset / maximumHorizontalOffset
        let percentageVerticalOffset: CGFloat = currentVerticalOffset / maximumVerticalOffset


        /*
         * below code changes the background color of view on paging the scrollview
         */
        //        self.scrollView(scrollView, didScrollToPercentageOffset: percentageHorizontalOffset)


        /*
         * below code scales the imageview on paging the scrollview
         */
        let percentOffset: CGPoint = CGPoint(x: percentageHorizontalOffset, y: percentageVerticalOffset)

        if(percentOffset.x > 0 && percentOffset.x <= 0.25) {

            slides[0].mainPic.transform = CGAffineTransform(scaleX: (0.25-percentOffset.x)/0.25, y: (0.25-percentOffset.x)/0.25)
            slides[1].mainPic.transform = CGAffineTransform(scaleX: percentOffset.x/0.25, y: percentOffset.x/0.25)

        } else if(percentOffset.x > 0.25 && percentOffset.x <= 0.50) {
            slides[1].mainPic.transform = CGAffineTransform(scaleX: (0.50-percentOffset.x)/0.25, y: (0.50-percentOffset.x)/0.25)
            slides[2].mainPic.transform = CGAffineTransform(scaleX: percentOffset.x/0.50, y: percentOffset.x/0.50)

        } else if(percentOffset.x > 0.50 && percentOffset.x <= 0.75) {
            slides[2].mainPic.transform = CGAffineTransform(scaleX: (0.75-percentOffset.x)/0.25, y: (0.75-percentOffset.x)/0.25)
            slides[3].mainPic.transform = CGAffineTransform(scaleX: percentOffset.x/0.75, y: percentOffset.x/0.75)

        } else if(percentOffset.x > 0.75 && percentOffset.x <= 1) {
            slides[3].mainPic.transform = CGAffineTransform(scaleX: (1-percentOffset.x)/0.25, y: (1-percentOffset.x)/0.25)
            slides[4].mainPic.transform = CGAffineTransform(scaleX: percentOffset.x, y: percentOffset.x)
        }
    }

    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        if segue.identifier == "findingClinitionSugue" {
            let destination = segue.destination as! FirstAvailableSearchViewController
            //destination.consumer = consumer
        }

        if (timer != nil) {
            timer?.invalidate()
        }
    }

    // protocol functions

    func initlizeSlides() {
        slides = createSlides()
        setupSlideScrollView(slides: slides)
    }

    func initlizeTimer() {
        scheduleTimer(5)
    }
}

Answer 1

问题可能与将contentSize height值初始设置为0有关，因此即使计时器希望移动scrollView，也无法做到这一点。

您可以尝试替换此行吗？

scrollView.contentSize = CGSize(width: scrollView.contentSize.width, height: 0)

使用：

scrollView.contentInsetAdjustmentBehavior = .never

Answer 2

取决于滚动视图中所需的应用程序和功能-您是否可以禁用滚动视图的用户交互，以便仍然可以通过编程方式移动它？

那将是

scrollView.isUserInteractionEnabled = false

这当然取决于您是否需要滚动视图中的项目进行交互

Answer 3

也许您可以继承UIScrollView的子类，并覆盖touchesBegan。

class CustomScrollView: UIScrollView {

    var touchesDisabled = false
    override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
        if touchesDisabled {
            // here parse the touches, if they go in the horizontal direction, allow scrolling
            // set tolerance for vertical movement
            let tolerance: CGFloat = 5.0
            let variance = touches.reduce(0, { Yvariation, touch in
                Yvariation + abs(touch.location(in: view).y - touch.previousLocation(in: view).y)
            })
            if variance <= tolerance * CGFloat(touches.count) {
                let Xtravelled = touches.reduce(0, { Xstep, touch in
                    Xstep + (touch.location(in: view).x - touch.previousLocation(in: view).x)
                })
                // scroll horizontally by the x component of hand gesture
                var newFrame: CGRect = scrollView.frame
                newFrame.origin.x += Xtravelled
                self.scrollRectToVisible(frame, animated: true)
            }
        }

        else {
            super.touchesBegan(touches: touches, withEvent: event)
        }
    }
}

这样，当您将touchesDisabled设置为true时，您可以手动水平移动滚动视图，同时禁用垂直移动。

Answer 4

这真是一个很有趣的问题...

虽然仅使用UIScrollView就能将UIScrollViewDelegate锁定到一个轴很容易，但是在以编程方式更改滚动时（如使用Timer一样，不可能提供平滑的滚动））。

下面，您会发现我刚刚写过一个DirectionLockingScrollView类，它会使您更轻松。您可以通过编程方式或通过界面生成器初始化UIScrollView。

它具有isHorizontalScrollingEnabled和isVerticalScrollingEnabled属性。

内部运作方式

它添加了与主UIScrollView相同的第二个“控件” DirectionLockingScrollView，并向其传播了所有用于主滚动视图的平移事件。每次“控件”滚动视图的边界更改时，更改都会传播到主滚动视图 BUT x和y被更改（基于isHorizontalScrollingEnabled和isVerticalScrollingEnabled）以禁止在请求的轴上滚动。

DirectionLockingScrollView.swift

/// `UIScrollView` subclass that supports disabling scrolling on any direction
/// while allowing the other direction to be changed programmatically (via
/// `setContentOffset(_:animated)` or `scrollRectToVisible(_:animated)` or changing the 
/// bounds etc.
///
/// Can be initialized programmatically or via the Interface Builder.
class DirectionLockingScrollView: UIScrollView {
    var isHorizontalScrollingEnabled = true
    var isVerticalScrollingEnabled = true

    /// The control scrollview is added below the `DirectionLockingScrollView`
    /// and is used to implement all native scrollview behaviours (such as bouncing)
    /// based on user input.
    ///
    /// It is required to be able to change the bounds of the `DirectionLockingScrollView`
    /// while maintaining scrolling in only one direction and allowing for setting the contentOffset
    /// (changing scrolling for any axis - even the disabled ones) programmatically.
    private let _controlScrollView = UIScrollView(frame: .zero)

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

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

    override func layoutSubviews() {
        super.layoutSubviews()
        updateCustomScrollViewFrame()
    }

    override func didMoveToSuperview() {
        super.didMoveToSuperview()
        guard let superview = superview else {
            _controlScrollView.removeFromSuperview()
            return
        }

        superview.insertSubview(_controlScrollView, belowSubview: self)
        updateCustomScrollViewFrame()
    }

    // MARK: - UIEvent propagation

    func viewIgnoresEvents(_ view: UIView?) -> Bool {
        let viewIgnoresEvents =
            view == nil ||
            view == self ||
            !view!.isUserInteractionEnabled ||
            !(view is UIControl && (view!.gestureRecognizers ?? []).count == 0)

        return viewIgnoresEvents
    }

    override func hitTest(_ point: CGPoint, with event: UIEvent?) -> UIView? {
        let view = super.hitTest(point, with: event)
        if viewIgnoresEvents(view) {
            return _controlScrollView
        }

        return view
    }

    // MARK: - Main scrollview settings propagation to `controlScrollView`

    override var contentInset: UIEdgeInsets {
        didSet {
            _controlScrollView.contentInset = contentInset
        }
    }

    override var contentScaleFactor: CGFloat {
        didSet {
            _controlScrollView.contentScaleFactor = contentScaleFactor
        }
    }

    override var contentSize: CGSize {
        didSet {
            _controlScrollView.contentSize = contentSize
        }
    }

    override var bounces: Bool {
        didSet {
            _controlScrollView.bounces = bounces
        }
    }

    override var bouncesZoom: Bool {
        didSet {
            _controlScrollView.bouncesZoom = bouncesZoom
        }
    }
}

extension DirectionLockingScrollView: UIScrollViewDelegate {
    func scrollViewDidScroll(_ scrollView: UIScrollView) {
        updateBoundsFromCustomScrollView(scrollView)
    }
}

private extension DirectionLockingScrollView {
    /// Propagates `controlScrollView` bounds to the actual scrollview.
    /// - Parameter scrollView: If the scrollview provided is not the `controlScrollView`
    //                          the main scrollview bounds are not updated.
    func updateBoundsFromCustomScrollView(_ scrollView: UIScrollView) {
        if scrollView != _controlScrollView {
            return
        }

        var newBounds = scrollView.bounds.origin
        if !isHorizontalScrollingEnabled {
            newBounds.x = self.contentOffset.x
        }

        if !isVerticalScrollingEnabled {
            newBounds.y = self.contentOffset.y
        }

        bounds.origin = newBounds
    }

    func installCustomScrollView() {
        _controlScrollView.delegate = self
        _controlScrollView.contentSize = contentSize
        _controlScrollView.showsVerticalScrollIndicator = false
        _controlScrollView.showsHorizontalScrollIndicator = false

        // The panGestureRecognizer is removed because pan gestures might be triggered
        // on subviews of the scrollview which do not ignore touch events (determined
        // by `viewIgnoresEvents(_ view: UIView?)`). This can happen for example
        // if you tap and drag on a button inside the scroll view.    
        removeGestureRecognizer(panGestureRecognizer)
    }

    func updateCustomScrollViewFrame() {
        if _controlScrollView.frame == frame { return }
        _controlScrollView.frame = frame
    }
}

用法

在您的应用中包含上述类之后，请不要忘记在 .xib 或 .storyboard 中将滚动视图的类更改为DirectionLockingScrollView em>。

然后按以下方式更新您的代码（仅更改两行，标记为// *****）。

class CaruselleScreenViewController: UIViewController, CaruselleScreenViewProtocol, UIScrollViewDelegate {
    var myPresenter: CaruselleScreenPresenterProtocol?

    @IBOutlet weak var pageControl: UIPageControl! 
    @IBOutlet weak var scrollView: DirectionLockingScrollView! // *****

    var slides:[CaruselleTipsCard] = [];


    var timer:Timer?
    var currentPageMultiplayer = 0

    override func viewDidLoad() {
        super.viewDidLoad()

        myPresenter = CaruselleScreenPresenter(controller: self)

        //initlizes view
        pageControl.numberOfPages = slides.count
        pageControl.currentPage = 0
        view.bringSubview(toFront: pageControl)

        scrollView.isHorizontalScrollingEnabled = false // *****

        //delegates
        scrollView.delegate = self

        ////blocks vertical movement
        scrollView.showsVerticalScrollIndicator = false
        //scrollView.contentSize  = CGSize(width: scrollView.contentSize.width, height: 0) //disable vertical
    }

    func scheduleTimer(_ timeInterval: TimeInterval){
        timer = Timer.scheduledTimer(timeInterval: timeInterval, target: self, selector: #selector(timerCall), userInfo: nil, repeats: false)
    }

    @objc func timerCall(){
        print("Timer executed")

        currentPageMultiplayer = currentPageMultiplayer + 1

        if (currentPageMultiplayer == 5) {
            currentPageMultiplayer = 0
        }
        pageControl.currentPage = currentPageMultiplayer
        scrollToPage(pageToMove: currentPageMultiplayer)

        scheduleTimer(5)
    }

    func scrollToPage(pageToMove: Int) {
        print ("new one")
        var frame: CGRect = scrollView.frame
        frame.origin.x = frame.size.width * CGFloat(pageToMove)
        frame.origin.y = -35
        scrollView.scrollRectToVisible(frame, animated: true)
    }


    func createSlides() -> [CaruselleTipsCard] {

        let slide1:CaruselleTipsCard = Bundle.main.loadNibNamed("CaruselleTipsCard", owner: self, options: nil)?.first as! CaruselleTipsCard
        slide1.mainPic.image = UIImage(named: "backlightingIllo")

        //
        let slide2:CaruselleTipsCard = Bundle.main.loadNibNamed("CaruselleTipsCard", owner: self, options: nil)?.first as! CaruselleTipsCard
        slide2.mainPic.image = UIImage(named: "comfortableIllo")

        //
        let slide3:CaruselleTipsCard = Bundle.main.loadNibNamed("CaruselleTipsCard", owner: self, options: nil)?.first as! CaruselleTipsCard
        slide3.mainPic.image = UIImage(named: "pharmacyIllo")

        //
        let slide4:CaruselleTipsCard = Bundle.main.loadNibNamed("CaruselleTipsCard", owner: self, options: nil)?.first as! CaruselleTipsCard
        slide4.mainPic.image = UIImage(named: "batteryIllo")

        //
        let slide5:CaruselleTipsCard = Bundle.main.loadNibNamed("CaruselleTipsCard", owner: self, options: nil)?.first as! CaruselleTipsCard
        slide5.mainPic.image = UIImage(named: "wiFiIllo")

        return [slide1, slide2, slide3, slide4, slide5]
    }

    func setupSlideScrollView(slides : [CaruselleTipsCard]) {
        scrollView.frame = CGRect(x: 0, y: 0, width: view.frame.width, height: view.frame.height)
        scrollView.contentSize = CGSize(width: view.frame.width * CGFloat(slides.count), height: view.frame.height)
        scrollView.isPagingEnabled = true

        for i in 0 ..< slides.count {
            slides[i].frame = CGRect(x: view.frame.width * CGFloat(i), y: 0, width: view.frame.width, height: view.frame.height)
            scrollView.addSubview(slides[i])
        }
    }


    //////

    /*
     * default function called when view is scrolled. In order to enable callback
     * when scrollview is scrolled, the below code needs to be called:
     * slideScrollView.delegate = self or
     */
    func scrollViewDidScroll(_ scrollView: UIScrollView) {
        let pageIndex = round(scrollView.contentOffset.x/view.frame.width)
        pageControl.currentPage = Int(pageIndex)

        let maximumHorizontalOffset: CGFloat = scrollView.contentSize.width - scrollView.frame.width
        let currentHorizontalOffset: CGFloat = scrollView.contentOffset.x

        // vertical
        let maximumVerticalOffset: CGFloat = scrollView.contentSize.height - scrollView.frame.height
        let currentVerticalOffset: CGFloat = scrollView.contentOffset.y

        let percentageHorizontalOffset: CGFloat = currentHorizontalOffset / maximumHorizontalOffset
        let percentageVerticalOffset: CGFloat = currentVerticalOffset / maximumVerticalOffset


        /*
         * below code changes the background color of view on paging the scrollview
         */
        //        self.scrollView(scrollView, didScrollToPercentageOffset: percentageHorizontalOffset)


        /*
         * below code scales the imageview on paging the scrollview
         */
        let percentOffset: CGPoint = CGPoint(x: percentageHorizontalOffset, y: percentageVerticalOffset)

        if(percentOffset.x > 0 && percentOffset.x <= 0.25) {

            slides[0].mainPic.transform = CGAffineTransform(scaleX: (0.25-percentOffset.x)/0.25, y: (0.25-percentOffset.x)/0.25)
            slides[1].mainPic.transform = CGAffineTransform(scaleX: percentOffset.x/0.25, y: percentOffset.x/0.25)

        } else if(percentOffset.x > 0.25 && percentOffset.x <= 0.50) {
            slides[1].mainPic.transform = CGAffineTransform(scaleX: (0.50-percentOffset.x)/0.25, y: (0.50-percentOffset.x)/0.25)
            slides[2].mainPic.transform = CGAffineTransform(scaleX: percentOffset.x/0.50, y: percentOffset.x/0.50)

        } else if(percentOffset.x > 0.50 && percentOffset.x <= 0.75) {
            slides[2].mainPic.transform = CGAffineTransform(scaleX: (0.75-percentOffset.x)/0.25, y: (0.75-percentOffset.x)/0.25)
            slides[3].mainPic.transform = CGAffineTransform(scaleX: percentOffset.x/0.75, y: percentOffset.x/0.75)

        } else if(percentOffset.x > 0.75 && percentOffset.x <= 1) {
            slides[3].mainPic.transform = CGAffineTransform(scaleX: (1-percentOffset.x)/0.25, y: (1-percentOffset.x)/0.25)
            slides[4].mainPic.transform = CGAffineTransform(scaleX: percentOffset.x, y: percentOffset.x)
        }
    }

    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        if segue.identifier == "findingClinitionSugue" {
            let destination = segue.destination as! FirstAvailableSearchViewController
            //destination.consumer = consumer
        }

        if (timer != nil) {
            timer?.invalidate()
        }
    }

    // protocol functions

    func initlizeSlides() {
        slides = createSlides()
        setupSlideScrollView(slides: slides)
    }

    func initlizeTimer() {
        scheduleTimer(5)
    }
}

Answer 5

如果我很好地理解了您的问题，可以随时通过此方式停止滚动

scrollView.isScrollEnabled = false

Answer 6

Using UIScrollViewDelegate (or KVO on scrollView's contentOffset), you can just counteract any vertical movement in the carousel. Something like this:

var oldYOffset: CGFloat ....

func scrollViewDidScroll(_ scrollView: UIScrollView) {
    let deltaY = oldYOffset - scrollView.contentOffset.y
    oldYOffset = scrollView.contentOffset.y
    scrollView.contentOffset.y -= deltaY
}

This offset change will not be visible to the user. You could even use this to increase the speed of the scrolling, invert the scrolling (pan left and scrollView scrolls right), or entirely lock the motion of the scrollView without touching isScrollEnabled, contentSize, etc.

在Swift 4.0中阻止UIScrollView上的垂直滚动的问题

6 个答案: