在UIScrollView中仅水平缩放UIView

Question

我尝试了其他帖子中的一些解决方案，但是无法解决我要发布的问题。

我有一个自定义UIView，它绘制一个SoundWave，并且包含一个UIScrollView。 UIScrollView包含一个主UIView，该UIView包含其他两个自定义UIView（标记左右）和UIImage视图（在此处渲染声波）。

private func initialize(){

    print("\(logClassName) initialize in Frame: \(frame)")

    //ScrollView
    addSubview(scrollView)
    scrollView.constraintToSuperViewEdges()


    //WaveView
    scrollView.addSubview(waveView)
    waveView.topAnchor.constraint(equalTo: scrollView.topAnchor, constant: 0).isActive = true
    waveView.leadingAnchor.constraint(equalTo: scrollView.leadingAnchor, constant: 0).isActive = true
    waveView.trailingAnchor.constraint(equalTo: scrollView.trailingAnchor, constant: 0).isActive = true
    waveView.heightAnchor.constraint(equalTo: scrollView.heightAnchor).isActive = true

    waveViewWidthConstraint = waveView.widthAnchor.constraint(equalToConstant: 1000)
    NSLayoutConstraint.activate([waveViewWidthConstraint])
    scrollView.contentSize = CGSize(width: waveViewWidthConstraint.constant, height: 0)

    //SoundWaveImageView
    waveView.addSubview(soundWaveImageView)
    soundWaveImageView.constraintToSuperViewEdges()


    //WaveView markers
    //TimeMarker
    waveView.addSubview(timeMarkerView)
    timeMarkerView.topAnchor.constraint(equalTo: waveView.topAnchor).isActive = true
    timeMarkerView.bottomAnchor.constraint(equalTo: waveView.bottomAnchor).isActive = true
    timeMarkerView.widthAnchor.constraint(equalToConstant: 1).isActive = true
    timerMarkerViewLeadingContraint = timeMarkerView.leadingAnchor.constraint(equalTo: waveView.leadingAnchor, constant: 20)
    NSLayoutConstraint.activate([timerMarkerViewLeadingContraint])


    //LeftMarker
    waveView.addSubview(leftMarkerView)
    leftMarkerView.topAnchor.constraint(equalTo: waveView.topAnchor).isActive = true
    leftMarkerView.bottomAnchor.constraint(equalTo: waveView.bottomAnchor).isActive = true
    leftMarkerView.widthAnchor.constraint(equalToConstant: leftMarkerView.triangleWidth).isActive = true
    leftMarkerViewLeadingConstraint = leftMarkerView.leadingAnchor.constraint(equalTo: waveView.leadingAnchor, constant: 0)
    NSLayoutConstraint.activate([leftMarkerViewLeadingConstraint])


    //RightMarker
    waveView.addSubview(rightMarkerView)
    rightMarkerView.topAnchor.constraint(equalTo: waveView.topAnchor).isActive = true
    rightMarkerView.bottomAnchor.constraint(equalTo: waveView.bottomAnchor).isActive = true
    rightMarkerView.widthAnchor.constraint(equalToConstant: rightMarkerView.triangleWidth).isActive = true
    rightMarkerViewLeadingConstraint = rightMarkerView.trailingAnchor.constraint(equalTo: waveView.leadingAnchor, constant: 50)
    NSLayoutConstraint.activate([rightMarkerViewLeadingConstraint])

}

如图所示，主UIView是对UIScrollView边缘的约束，而宽度约束是根据需要而变化的总长度。负责该功能的函数如下：

private func updateWidthConstraintValue(_ newWidth:CGFloat){

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

}

当实现UIScrollView的缩放时，它可以工作，但是可以垂直和水平缩放（如预期的那样），但是我只想水平实现。到目前为止，我已经知道了：

func scrollViewDidZoom(_ scrollView: UIScrollView) {

    print("\(logClassName) TEST -> scrollView did zoom \(scrollView.zoomScale)")
    expandHorizontally(withScale: scrollView.zoomScale)
    //scrollView.contentOffset = CGPoint(x: scrollView.contentOffset.x, y: 0)
    //scrollView.contentSize = CGSize(width: scrollView.contentSize.width, height: scrollView.frame.height)
}

func viewForZooming(in scrollView: UIScrollView) -> UIView? {

    return waveView

}

private func expandHorizontally(withScale scale:CGFloat){

    let scaledWidth = currentWaveViewWidth * scale
    print("\(logClassName) TEST -> scaledWidth = \(scaledWidth)")

    updateWidthConstraintValue(scaledWidth)
    // Adjust content size and content offset
    scrollView.contentSize = CGSize(width: waveViewWidthConstraint.constant,
                                    height: 0);
    scrollView.contentOffset = CGPoint(x: scrollView.contentOffset.x,
                                       y: scrollView.contentOffset.y);

}

UI变量的声明如下：

lazy private (set) var scrollView:UIScrollView = {

    let rtView = UIScrollView()

    rtView.translatesAutoresizingMaskIntoConstraints = false
    rtView.backgroundColor = .clear

    rtView.bounces = false
    rtView.bouncesZoom = false

    rtView.minimumZoomScale = 1
    rtView.maximumZoomScale = 3

    rtView.delegate = self

    return rtView

}()

private (set) lazy var waveView:UIView = {

    let rtView = UIView()

    rtView.translatesAutoresizingMaskIntoConstraints = false
    rtView.backgroundColor = .clear
    rtView.addGestureRecognizer(UITapGestureRecognizer(target: self,
                                                       action: #selector(waveViewDidTouch)))

    return rtView

}()
private (set) var waveViewWidthConstraint = NSLayoutConstraint()

private (set) lazy var soundWaveImageView:UIImageView = {

    let rtView = UIImageView()

    rtView.translatesAutoresizingMaskIntoConstraints = false

    return rtView

}()

private (set) lazy var timeMarkerView:UIView = {
    let rtView = UIView()

    rtView.translatesAutoresizingMaskIntoConstraints = false
    rtView.backgroundColor = UIColor.AppColors.defaultTint

    return rtView
}()
private var timerMarkerViewLeadingContraint = NSLayoutConstraint()

private (set) lazy var leftMarkerView:MarkerView = {

    let rtView = MarkerView(title: AppHelper.printLocalized(withKey: "messages.start", targetSpecific: false), markerDirection: .right)

    rtView.translatesAutoresizingMaskIntoConstraints = false
    rtView.delegate = self

    return rtView

}()
private var leftMarkerViewLeadingConstraint = NSLayoutConstraint()

private (set) lazy var rightMarkerView:MarkerView = {

    let rtView = MarkerView(title: AppHelper.printLocalized(withKey: "messages.end", targetSpecific: false), markerDirection: .left)

    rtView.translatesAutoresizingMaskIntoConstraints = false
    rtView.delegate = self

    return rtView

}()
private var rightMarkerViewLeadingConstraint = NSLayoutConstraint()

我试图把所有相关信息放进去，因为这是一个大类。

Answer 1

我已经找到了临时解决方案，谢谢LaurentMaquet。在某个时候，我将发布最终的soundWaveView，目前仍在开发中。

所做的更改是：

1-为soundWave创建一个自定义类。

class WaveView:UIView{
    var unzoomedViewHeight: CGFloat = 0

    override var transform: CGAffineTransform{
        get{ return super.transform }
        set{
            var t = newValue
            t.d = 1.0
            t.ty = (1.0 - t.a) * unzoomedViewHeight/2
            super.transform = t
        }
    }

    override func layoutSubviews() {
        super.layoutSubviews()

        unzoomedViewHeight = frame.size.height
        print("\(logClassName) did layout to \(AppHelper.traitStatus) -> frame = \(frame)")

    }

}

2-将我的soundView变量设为SoundView

private (set) lazy var waveView:WaveView = {

    let rtView = WaveView()

    rtView.translatesAutoresizingMaskIntoConstraints = false
    rtView.backgroundColor = .clear
    rtView.addGestureRecognizer(UITapGestureRecognizer(target: self,
                                                       action: #selector(waveViewDidTouch)))

    return rtView

}()

结果