如何在 Swift 中向响应式网站添加后退按钮

Question

我使用 WKWebView 快速创建了一个小应用程序，允许用户访问响应式网站，登录页面有一个选项，允许用户访问完整的公司网站，一旦该网站页面显示，我没有返回按钮选项带您返回上一页。如何快速添加用户可以选择的后退按钮以使他们返回原始响应式网站页面。我是新手，任何帮助将不胜感激。我包括我的代码副本（ViewController.swift）。

       ViewController.swift
       //  wfmApp
       //
       //  Created by Stefan Sanders on 9/13/18.
       //  Copyright © 2018 Stefan Sanders. All rights reserved.
       //

    import UIKit
    import WebKit

    class ViewController: UIViewController {

    @IBOutlet weak var wenView: WKWebView!

    @IBOutlet weak var activityIndicator: UIActivityIndicatorView!

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        let URLString = "https://www.wastefreemail.com/app"
        let request = URLRequest(url:URL(string:URLString)!)
        self.wenView.load(request)

        self.wenView.addObserver(self, forKeyPath: #keyPath(WKWebView.isLoading), options: .new, context: nil)
    }

    override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?) {
        if keyPath == "loading" {
            if wenView.isLoading {
                activityIndicator.startAnimating()
                activityIndicator.isHidden = false
            } else {
                activityIndicator.stopAnimating()
            }
        }
    }
    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }


}

Answer 1

此代码返回上一页

import UIKit
import WebKit

class ViewController: UIViewController {

    @IBOutlet weak var wenView: WKWebView!

    @IBOutlet weak var activityIndicator: UIActivityIndicatorView!

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        let URLString = "https://www.wastefreemail.com/app"
        let request = URLRequest(url:URL(string:URLString)!)
        self.wenView.load(request)

        self.wenView.addObserver(self, forKeyPath: #keyPath(WKWebView.isLoading), options: .new, context: nil)
    }

    override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?) {
        if keyPath == "loading" {
            if wenView.isLoading {
                activityIndicator.startAnimating()
                activityIndicator.isHidden = false
            } else {
                activityIndicator.stopAnimating()
            }
        }
    }
    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

    @IBAction func goBack(_ sender: Any) {
        wenView.goBack()
    }

}

Answer 2

请检查 Wkwebview backForwardList 你会得到完整的后退项目列表，从列表中你可以得到 backItem 并且你可以检查 backitem 是否不为零，这意味着你可以返回并且和你一样可以得到 @ 987654324@ 也可以显示前进按钮。有关更多信息，请参阅此链接back forward list

Answer 3

使用 swift 5 更新。

import UIKit
import WebKit

class WebViewViewController: UIViewController, WKNavigationDelegate {
    var webView: WKWebView!

override func loadView() {
    webView = WKWebView()
    webView.navigationDelegate = self
    view = webView
}

override func viewDidLoad() {
    super.viewDidLoad()

    let url = URL(string: "https://www.apple.com/in/")!
    webView.load(URLRequest(url: url))
    webView.allowsBackForwardNavigationGestures = true
    navigationItem.rightBarButtonItems =
        [ UIBarButtonItem(title: ">", style: .plain, target: self, action: #selector(goForward)),
          UIBarButtonItem(title: "<", style: .plain, target: self, action: #selector(goBack))
    ]
    let loader = UIActivityIndicatorView()
    if webView.isLoading {
        
        loader.startAnimating()
        navigationItem.leftBarButtonItem = UIBarButtonItem(customView: loader)
    } else {
        
        navigationItem.leftBarButtonItem = UIBarButtonItem(title: "Back", style: .plain, target: self, action: #selector(refreshButton))
    }
}

@objc func goBack() {
    webView.goBack()
}
@objc func refreshButton() {
    navigationController?.popToRootViewController(animated: true)
}
@objc func goForward() {
    webView.goForward()
}

func webView(_ webView: WKWebView, didFinish Navigation: WKNavigation!) {
        title = "Demo"
    navigationItem.leftBarButtonItem = UIBarButtonItem(title: "Back", style: .plain, target: self, action: #selector(refreshButton))

    }

}