我正在创建带有“ X”作为关闭/关闭按钮的涂鸦页面。 我还有一个“清除”按钮，可删除已制作的涂鸦。

我的问题是，当我按清除键时，即使X按钮消失了，如何防止这种情况发生？

这是我当前的应用。

这是我的Doodle课程，可让我在视图上绘画。

import UIKit

class DoodleView: UIView {

    var lineColor:UIColor!
    var lineWidth:CGFloat!
    var path:UIBezierPath!
    var touchPoint:CGPoint!
    var startingPoint:CGPoint!

    override func layoutSubviews() {
        self.clipsToBounds = true
        self.isMultipleTouchEnabled = false

        lineColor = UIColor.white
        lineWidth = 10
    }


    override func touchesBegan(_ touches: Set<UITouch>,with event: UIEvent?) {
        let touch = touches.first
        startingPoint = touch?.location(in: self)
    }

    override func touchesmoved(_ touches: Set<UITouch>,with event: UIEvent?) {
        let touch = touches.first
        touchPoint = touch?.location(in: self)

        path = UIBezierPath()
        path.move(to: startingPoint)
        path.addLine(to: touchPoint)
        startingPoint = touchPoint

        drawShapelayer()
    }

    func drawShapelayer() {
        let shapelayer = CAShapelayer()
        shapelayer.path = path.cgPath
        shapelayer.strokeColor = lineColor.cgColor
        shapelayer.lineWidth = lineWidth
        shapelayer.fillColor = UIColor.clear.cgColor
        self.layer.addSublayer(shapelayer)
        self.setNeedsDisplay()
    }

    func clearCanvas() {
        path.removeAllPoints()
        self.layer.sublayers = nil
        self.setNeedsDisplay()
    }
}

这是控制视图控制器的类。

import UIKit

class DoodlePageViewController: UIViewController {


    @IBOutlet weak var doodleView: DoodleView!

    override func viewDidLoad() {
        super.viewDidLoad()

        // Do any additional setup after loading the view.
    }


    @IBaction func clearDoodle(_ sender: Any) {
        doodleView.clearCanvas()
    }


    @IBaction func CloseDoodlePage(_ sender: Any) {
        dismiss(animated: true,completion: nil)
    }
}