关闭按钮不在Swift游乐场工作

Question

我正在WWDC的Swift游乐场工作。我需要一个关闭Web视图和工具栏的UI按钮（该按钮称为closeButton，函数位于按钮的底部），并在单击时返回到先前的屏幕（第一个视图）。下面的代码是我到目前为止输入的Swift：

import UIKit
import WebKit
import PlaygroundSupport
import Foundation

PlaygroundPage.current.needsIndefiniteExecution = true

class MyViewController : UIViewController {
    let cardView = UIView()
    let accountButton = UIButton()
    let coverImageView = UIImageView()
    let swiftLogoView = UIImageView()
    let openLabel = UILabel()
    let titleLabel = UILabel()
    let label = UILabel()
    let captionLabel = UILabel()
    let descriptionLabel = UILabel()
    let backgroundImageView = UIImageView()
    let closeButton = UIButton()
    let openButton = UIButton()
    let doneButton = UIButton()
    let url1 = URL(string: "https://youtube.com/embed/uuxXHAKA1WY")!
    let alertController = UIAlertController(title: "Who Made This Playground:", message: "Mark Bruckert made this playground for WWDC 2018. He is a Web and Graphic Designer learning Swift and IOS Design. He would love to attend this year, to learn the new frameworks revealed at the event and have IOS Engineers review his designs and code.", preferredStyle: .alert)
    let defaultAction = UIAlertAction(title: "Close", style: .default, handler: nil)
    let menuBar = UIView()
    let doneLabel = UILabel()
    let webView = UIWebView()

    let cardView2 = UIView()
    let coverImageView2 = UIImageView()
    let titleLabel2 = UILabel()
    let captionLabel2 = UILabel()
    let descriptionLabel2 = UILabel()
    let backgroundImageView2 = UIImageView()
    let url2 = URL(string: "https://youtu.be/uuxXHAKA1WY")!

    override func loadView() {
        let view = UIView()
        view.backgroundColor = .white

        label.frame = CGRect(x: 20, y: 30, width: 272, height: 38)
        label.text = "Dev Tutorials:"
        label.textColor = .black
        label.font = UIFont.systemFont(ofSize: 32, weight: .bold)

        openLabel.frame = CGRect(x: 140, y: 215, width: 272, height: 38)
        openLabel.text = "Play Video"
        openLabel.textColor = .black
        openLabel.font = UIFont.systemFont(ofSize: 32, weight: .semibold)
        self.openLabel.alpha = 0
        openLabel.layer.zPosition = 5

        doneLabel.frame = CGRect(x: 25, y: 5, width: 272, height: 38)
        doneLabel.text = "Done"
        doneLabel.textColor = .white
        doneLabel.font = UIFont.systemFont(ofSize: 32, weight: .light)
        openLabel.layer.zPosition = 7
        doneButton.addTarget(self, action: #selector(doneButtonTapped), for: .touchUpInside
        )

        cardView.frame = CGRect(x: 60, y: 100, width: 300, height: 250)
        cardView.layer.cornerRadius = 14
        cardView.backgroundColor = #colorLiteral(red: 1, green: 1, blue: 1, alpha: 1)
        cardView.layer.shadowOpacity = 0.25
        cardView.layer.shadowOffset = CGSize(width: 0, height: 10)
        cardView.layer.shadowRadius = 10

        cardView2.frame = CGRect(x: 60, y: 100, width: 300, height: 250)
        cardView2.layer.cornerRadius = 14
        cardView2.backgroundColor = #colorLiteral(red: 1, green: 1, blue: 1, alpha: 1)
        cardView2.layer.shadowOpacity = 0.25
        cardView2.layer.shadowOffset = CGSize(width: 0, height: 10)
        cardView2.layer.shadowRadius = 10

        titleLabel.frame = CGRect(x: 16, y: 16, width: 272, height: 38)
        titleLabel.text = "Portals with ARKit"
        titleLabel.textColor = .white
        titleLabel.font = UIFont.systemFont(ofSize: 32, weight: .semibold)

        captionLabel.frame = CGRect(x: 16, y: 204, width: 272, height: 40)
        captionLabel.text = "by Jared Davidson"
        captionLabel.textColor = .white
        captionLabel.numberOfLines = 0

        descriptionLabel.frame = CGRect(x: 20, y: 400, width: 335, height: 132)
        descriptionLabel.text = "In this tutorial, you will learn how to use ARKit by Apple to transport yourself through a portal."
        descriptionLabel.textColor = .black
        descriptionLabel.numberOfLines = 10
        descriptionLabel.alpha = 0

        coverImageView.frame = CGRect(x: 0, y: 0, width: 300, height: 250)
        coverImageView.contentMode = .scaleAspectFill
        coverImageView.image = #imageLiteral(resourceName: "Cover.jpg")
        coverImageView.clipsToBounds = true

        swiftLogoView.frame = CGRect(x: 8, y: 8, width: 35, height: 35)
        swiftLogoView.contentMode = .scaleAspectFill
        swiftLogoView.image = #imageLiteral(resourceName: "Swift_logo.png")
        swiftLogoView.clipsToBounds = true
        coverImageView.layer.cornerRadius = 14

        accountButton.frame = CGRect(x: 360, y: 20, width: 55, height: 55)
        accountButton.backgroundColor = #colorLiteral(red: 0.803921580314636, green: 0.803921580314636, blue: 0.803921580314636, alpha: 1.0)
        accountButton.layer.cornerRadius = 30
        accountButton.addTarget(self, action: #selector(accountButtonTapped), for: .touchUpInside)

        closeButton.frame = CGRect(x: 360, y: 20, width: 28, height: 28)
        closeButton.backgroundColor = #colorLiteral(red: 0, green: 0, blue: 0, alpha: 0.5)
        closeButton.layer.cornerRadius = 14
        closeButton.setImage(#imageLiteral(resourceName: "Action-Close@2x.png"), for: .normal)
        closeButton.addTarget(self, action: #selector(closeButtonTapped), for: .touchUpInside)
        closeButton.alpha = 0

        openButton.frame = CGRect(x: 100, y: 200, width: 220, height: 75)
        openButton.backgroundColor = #colorLiteral(red: 1.0, green: 1.0, blue: 1.0, alpha: 1.0)
        openButton.layer.cornerRadius = 14
        openButton.addTarget(self, action: #selector(openButtonTapped), for: .touchUpInside)
        openButton.alpha = 0

        doneButton.frame = CGRect(x: 10, y: 5, width: 130, height: 50)
        doneButton.layer.borderWidth = 3.0
        doneButton.layer.borderColor = #colorLiteral(red: 1.0, green: 1.0, blue: 1.0, alpha: 1.0)
        doneButton.layer.cornerRadius = 14
        doneButton.addTarget(self, action: #selector(doneButtonTapped), for: .touchUpInside)


        cardView.addSubview(coverImageView)


        cardView.addSubview(openLabel)

        doneButton.addSubview(doneLabel)
        cardView.addSubview(closeButton)

        cardView.addSubview(openButton)

        menuBar.addSubview(doneButton)
        cardView.addSubview(descriptionLabel)

        view.addSubview(cardView)

        view.addSubview(label)

        view.addSubview(accountButton)

        let tap = UITapGestureRecognizer(target: self, action: #selector(cardViewTapped))
        cardView.addGestureRecognizer(tap)
        cardView.isUserInteractionEnabled = true

        doneButton.isUserInteractionEnabled = true

        self.view = view
    }

    @objc func cardViewTapped() {
        let animator = UIViewPropertyAnimator(duration: 0.7, dampingRatio: 0.7) {
            self.cardView.frame = CGRect(x: 0, y: 0, width: 450, height: 667)

            self.label.layer.isHidden = true
            self.cardView.layer.cornerRadius = 0
            self.titleLabel.frame = CGRect(x: 20, y: 20, width: 374, height: 38)
            self.captionLabel.frame = CGRect(x: 20, y: 370, width: 272, height: 40)
            self.descriptionLabel.alpha = 1
            self.coverImageView.frame = CGRect(x: 0, y: 0, width: 450, height: 420)
            self.coverImageView.layer.cornerRadius = 0

            self.closeButton.alpha = 1

            self.openButton.alpha = 0.7

            self.accountButton.alpha = 0

            self.openLabel.alpha = 1
        }
        animator.startAnimation()
    }

    @objc func closeButtonTapped() {
        let animator = UIViewPropertyAnimator(duration: 0.7, dampingRatio: 0.7) {
            self.cardView.frame = CGRect(x: 60, y: 100, width: 300, height: 250)
            self.cardView.layer.cornerRadius = 14
            self.titleLabel.frame = CGRect(x: 16, y: 16, width: 272, height: 38)
            self.captionLabel.frame = CGRect(x: 16, y: 204, width: 272, height: 40)
            self.descriptionLabel.alpha = 0
            self.coverImageView.frame = CGRect(x: 0, y: 0, width: 300, height: 250)
            self.coverImageView.layer.cornerRadius = 14
            self.closeButton.alpha = 0

            self.label.layer.isHidden = false

            self.openButton.alpha = 0

            self.openLabel.alpha = 0

            self.accountButton.alpha = 1
        }
        animator.startAnimation()
    }

    @objc func openButtonTapped() {

        let view = UIView(frame: CGRect(x: 0, y: 0, width: 320, height: 600))
        view.backgroundColor = UIColor.lightGray
        PlaygroundPage.current.liveView = view

        menuBar.translatesAutoresizingMaskIntoConstraints = false
        view.addSubview(menuBar)
        menuBar.topAnchor.constraint(equalTo: view.topAnchor).isActive = true
        menuBar.leftAnchor.constraint(equalTo: view.leftAnchor).isActive = true
        menuBar.rightAnchor.constraint(equalTo: view.rightAnchor).isActive = true
        menuBar.heightAnchor.constraint(equalToConstant: 64.0).isActive = true
        menuBar.backgroundColor = #colorLiteral(red: 0.803921580314636, green: 0.803921580314636, blue: 0.803921580314636, alpha: 1.0)

        let toolbar = UIView()
        toolbar.translatesAutoresizingMaskIntoConstraints = false
        view.addSubview(toolbar)
        toolbar.bottomAnchor.constraint(equalTo: view.bottomAnchor).isActive = true
        toolbar.leftAnchor.constraint(equalTo: view.leftAnchor).isActive = true
        toolbar.rightAnchor.constraint(equalTo: view.rightAnchor).isActive = true
        toolbar.heightAnchor.constraint(equalToConstant: 64.0).isActive = true
        toolbar.backgroundColor = #colorLiteral(red: 0.803921580314636, green: 0.803921580314636, blue: 0.803921580314636, alpha: 1.0)

        webView.translatesAutoresizingMaskIntoConstraints = false
        view.addSubview(webView)
        webView.topAnchor.constraint(equalTo: menuBar.bottomAnchor, constant: 8.0).isActive = true
        webView.bottomAnchor.constraint(equalTo: toolbar.topAnchor, constant: -8.0).isActive = true
        webView.leftAnchor.constraint(equalTo: view.leftAnchor).isActive = true
        webView.rightAnchor.constraint(equalTo: view.rightAnchor).isActive = true
        webView.loadRequest(URLRequest(url: URL(string:"https://youtube.com/embed/uuxXHAKA1WY")!))
    }

    @objc func accountButtonTapped() {
        present(alertController, animated: true, completion: nil)
        alertController.addAction(defaultAction)
    }

    @objc func doneButtonTapped() {
        self.webView.alpha = 0
        self.view.alpha = 0
    }
}
// Present the view controller in the Live View window
PlaygroundPage.current.liveView = MyViewController()

先谢谢你的帮助， 马克B.

Answer 1

在方法 openButtonTapped 中，本地变量查看会为您的代码带来问题。此外，您再次调用 liveView 。我修改了你的代码，假设最后一个屏幕将转到上一个。

首先，将 toolBar 声明为 menuBar 之类的成员变量。并输入以下代码。点击完成按钮将转到上一个。

 @objc func openButtonTapped() {
    view.backgroundColor = UIColor.cyan
    menuBar.translatesAutoresizingMaskIntoConstraints = false
    view.addSubview(menuBar)
    menuBar.topAnchor.constraint(equalTo: view.topAnchor).isActive = true
    menuBar.leftAnchor.constraint(equalTo: view.leftAnchor).isActive = true
    menuBar.rightAnchor.constraint(equalTo: view.rightAnchor).isActive = true
    menuBar.heightAnchor.constraint(equalToConstant: 64.0).isActive = true
    menuBar.backgroundColor = #colorLiteral(red: 0.803921580314636, green: 0.803921580314636, blue: 0.803921580314636, alpha: 1.0)

    toolbar.translatesAutoresizingMaskIntoConstraints = false
    view.addSubview(toolbar)
    toolbar.bottomAnchor.constraint(equalTo: view.bottomAnchor).isActive = true
    toolbar.leftAnchor.constraint(equalTo: view.leftAnchor).isActive = true
    toolbar.rightAnchor.constraint(equalTo: view.rightAnchor).isActive = true
    toolbar.heightAnchor.constraint(equalToConstant: 64.0).isActive = true
    toolbar.backgroundColor = #colorLiteral(red: 0.803921580314636, green: 0.803921580314636, blue: 0.803921580314636, alpha: 1.0)


    webView.translatesAutoresizingMaskIntoConstraints = false
    view.addSubview(webView)
    webView.topAnchor.constraint(equalTo: menuBar.bottomAnchor, constant: 8.0).isActive = true
    webView.bottomAnchor.constraint(equalTo: toolbar.topAnchor, constant: -8.0).isActive = true
    webView.leftAnchor.constraint(equalTo: view.leftAnchor).isActive = true
    webView.rightAnchor.constraint(equalTo: view.rightAnchor).isActive = true
    webView.loadRequest(URLRequest(url: URL(string:"https://youtube.com/embed/uuxXHAKA1WY")!))
}

@objc func accountButtonTapped() {
    present(alertController, animated: true, completion: nil)
    alertController.addAction(defaultAction)
}

@objc func doneButtonTapped() {
    print("test")
    self.webView.stopLoading()
    self.webView.alpha = 0
    toolbar.removeFromSuperview()
    menuBar.removeFromSuperview()
}