ios - Swift到SwiftUI的迁移问题

Question

所以我不完全了解如何在SwiftUI中实现它才能正常工作。

我有以下代码:

class RulerView: UIView {

// MARK: - Constants
private struct Constants {

    static let labelWidth: CGFloat = 100
    static let labelHeight: CGFloat = 20
    static let labelMarginTop: CGFloat = 5
    static let rulerHeight: CGFloat = 100

}

// MARK: - Properties
override var tintColor: UIColor! {

    didSet { _updateStyle().setNeedsDisplay() }

}

internal let unit: Length.Unit
internal let length: CGFloat

private var lineWidth: CGFloat
private var replicatorLayer: CAReplicatorLayer?
private var labels: [UILabel]?

private var lengthUnitWidth: CGFloat {

    switch unit {

        case .centimeter:
            return Length.pixels(fromCentimeter: 1.0)

        case .inch:
            return Length.pixels(fromInch: 1.0)

    }

}

// MARK: - View Life Cycle
required init?(coder aDecoder: NSCoder) {

    fatalError("init(coder:) has not been implemented")

}
/*
required init?(coder: NSCoder) {

    fatalError("init(coder:) has not been implemented")

}
*/

init(unit: Length.Unit, length: CGFloat, lineWidth: CGFloat) {

    self.unit = unit
    self.length = length
    self.lineWidth = lineWidth

    super.init(frame: .zero)

    let rulerWidth = lengthUnitWidth * length

    frame = .init(x: 0, y: 0, width: rulerWidth, height: Constants.rulerHeight)

    _setupLabels()

}

override func didMoveToWindow() {

    super.didMoveToWindow()

    _updateStyle()

}

override func draw(_ rect: CGRect) {

    super.draw(rect)

    replicatorLayer?.removeFromSuperlayer()

    replicatorLayer = CAReplicatorLayer()

    if let replicatorLayer = replicatorLayer {

        replicatorLayer.instanceCount = Int(ceil(length))

        replicatorLayer.instanceTransform = CATransform3DMakeTranslation(lengthUnitWidth, 0, 0)

        let unitLayer = LengthUnitLayer(unit: unit, lineWidth: lineWidth, lineColor: tintColor.cgColor, height: frame.height)

        unitLayer.frame = CGRect(x: -lineWidth / 2, y: 0, width: unitLayer.bounds.width, height: (bounds.height - Constants.labelHeight - Constants.labelMarginTop))

        unitLayer.setNeedsDisplay()

        replicatorLayer.addSublayer(unitLayer)

        layer.addSublayer(replicatorLayer)

    }

    labels?.enumerated().forEach { (offset, element) in

        element.frame = .init(x: (CGFloat(offset) * lengthUnitWidth - Constants.labelWidth / 2),
        y: (bounds.height - Constants.labelHeight),
        width: Constants.labelWidth,
        height: Constants.labelHeight)

    }

}

// MARK: - Setup
@discardableResult
private func _setupLabels() -> Self {

    labels?.forEach { $0.removeFromSuperview() }

    labels = [UILabel]()

    for i in 0...Int(ceil(length)) {

        let label = UILabel()

        label.text = "\(i)"

        label.textAlignment = .center

        addSubview(label)

        labels?.append(label)

    }

    return self

}

// MARK: - Layout
@discardableResult
private func _updateStyle() -> Self {

    labels?.forEach { $0.textColor = tintColor }

    return self

}

}

我试图这样在 ContentView中调用它:

var viewSize = UIScreen.main.bounds.size

var body: some View {

    RulerView(coder: viewSize)

}

但这不起作用吗？有谁知道我该如何解决？

Answer 1

需要将UIView包装到UIViewRepresentable中，以便在SwiftUI中使用，如下所示。

public struct RulerViewRep: UIViewRepresentable {

    public func makeUIView(context: Context) -> RulerView {
        return RulerView()
    }

    public func updateUIView(_ uiView: RulerView, context: Context) {
    }
}

然后用它

var body: some View {
    // by default consumes all space, so UIScreen.main.bounds not needed
    RulerView() 

}