在 Swift 中创建可重用视图并添加完成处理程序

Question

我创建了一个 sliderView，并添加了一个 UIPanGesture，我创建了一个单独的 UIView 来处理这个滑块。我希望能够在我需要的不同 ViewController 中调用此 SliderView 但是当我尝试运行我的代码时 IT crashed.I 也想传递一个完成处理程序来处理我所在的 ViewCONtrollers 中的事件会需要它。我试图通过创建一个 UIView 并在多个屏幕中使用它来遵循 DRY 过程。以下是我目前的代码

class TripView: UIView {

    var shouldSetupConstraints = true
    var startingFrame: CGRect?

    var sliderView: UIView!
    var sliderImage: UIImageView!

    let screenSize = UIScreen.main.bounds

    override init(frame: CGRect){
        super.init(frame: frame)
        swipeFunc()
        sliderView = UIImageView(frame: CGRect.zero)
        sliderView.backgroundColor = UIColor.green

        sliderView.autoSetDimension(.height, toSize: screenSize.width / 6)

        self.addSubview(sliderView)

        sliderImage = UIImageView(frame: CGRect.zero)
        sliderImage.backgroundColor = UIColor.clear
        sliderImage.image = UIImage(named: "icons8-double_right_filled.png")
        sliderImage.contentMode = .scaleAspectFit

        sliderImage.autoSetDimension(.width, toSize: screenSize.width / 6)
        sliderImage.autoSetDimension(.height, toSize: screenSize.width / 6)

        self.addSubview(sliderImage)


    }

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

    override func updateConstraints() {
        if(shouldSetupConstraints) {

            sliderView.autoPinEdgesToSuperviewSafeArea(with: UIEdgeInsets.zero, excludingEdge: .bottom)
            sliderImage.autoPinEdge(toSuperviewEdge: .left)
            sliderImage.autoPinEdge(.bottom, to: .bottom, of: sliderView, withOffset: 0.0)

            shouldSetupConstraints = false
        }

        super.updateConstraints()
    }
}

extension TripView {

    private func swipeFunc() {

        let swipeGesture = UIPanGestureRecognizer(target: self, action: #selector(acknowledgeSwiped(sender:)))
        sliderImage.addGestureRecognizer(swipeGesture)
        sliderImage.isUserInteractionEnabled = true
        swipeGesture.delegate = self as? UIGestureRecognizerDelegate
    }

    @objc func acknowledgeSwiped(sender: UIPanGestureRecognizer) {
        if let sliderView = sender.view {
            let translation = sender.translation(in: sliderView)
            switch sender.state {
            case .began:
                startingFrame = sliderImage.frame
                fallthrough
            case .changed:
                if let startFrame = startingFrame {

                    var movex = translation.x
                    if movex < -startFrame.origin.x { movex = -startFrame.origin.x }

                    let xMax = sliderView.frame.width - startFrame.origin.x - startFrame.width
                    if movex > xMax {
                        movex = xMax

      // I WANT TO PASS A COMPLETION HANDLER HERE. TO BE ABLE TO HANDLE OTHER     EVENTS IN VIEWCONTROLLERS

                    }

                    var movey = translation.y
                    if movey < -startFrame.origin.y { movey = -startFrame.origin.y }

                    let yMax = sliderView.frame.height - startFrame.origin.y - startFrame.height
                    if movey > yMax {
                        movey = yMax

                    }

                    sliderView.transform = CGAffineTransform(translationX: movex, y: movey)
                }
            default: // .ended and others:
                UIView.animate(withDuration: 0.1, animations: {
                    sliderView.transform = CGAffineTransform.identity
                })
            }
        }
    }

}

Answer 1

您正在调用 swipeFunc，它在 sliderImage 初始化之前访问 sliderImage。

您必须将 swipeFunc() 移动到 init 方法的末尾。

实际上，没有必要使用隐式解包选项。您可以使用非可选的来防止崩溃：

let sliderView: UIView = UIImageView(frame: CGRect.zero)
let sliderImage: UIImageView = UIImageView(frame: CGRect.zero)

因为你实际上有两个初始化器，你可能应该初始化两者中的所有内容：

let sliderView: UIView = UIImageView(frame: CGRect.zero)
let sliderImage: UIImageView = UIImageView(frame: CGRect.zero)

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

    commonInit()
}

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

    commonInit()
}

private func commonInit() {
    sliderView.backgroundColor = UIColor.green
    sliderView.autoSetDimension(.height, toSize: screenSize.width / 6)

    self.addSubview(sliderView)

    sliderImage.backgroundColor = UIColor.clear
    sliderImage.image = UIImage(named: "icons8-double_right_filled.png")
    sliderImage.contentMode = .scaleAspectFit

    sliderImage.autoSetDimension(.width, toSize: screenSize.width / 6)
    sliderImage.autoSetDimension(.height, toSize: screenSize.width / 6)

    self.addSubview(sliderImage)

    swipeFunc()
}

关于回调，只需声明一个属性:

class TripView: UIView {
    var onChange: (() -> Void)?
}

并且在每次更改电话时：

onChange?()

然后在您的控制器中您可以：

var tripView: TripView = ...
tripView.onChange = {
  // handle the event
}

Answer 2

您可以将完成处理程序添加为内部变量，或在初始化程序中传递一个。

例如：

class TripView: UIView {
    typealias Callback = () -> ()
    var callback: Callback

    ...
}

然后在你想触发回调的地方，直接调用：

callback()

或者您可以定义一个委托

protocol TripViewDelegate {
    func didDoSomething(for view: TripView)
}

class TripView: UIView {
    weak var tripViewDelegate: TripViewDelegate?
    // ...
}

然后调用

tripViewDelegate?.didDoSomething(for: self)

在 Swift 中创建可重用视图并添加完成处理程序

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