iOS-如何以编程方式创建WKWebView后退按钮? [英] iOS - How to create WKWebView Back Button programmatically?

问题描述

我正在尝试为我的iOS WKWebView应用程序创建一个后退按钮，这样当用户单击该按钮时，会将他们带到上一个WKWebView页面.我发现了很多关于如何使用IB而不是直接代码的教程.这是我到目前为止的内容:

I am attempting to create a back button for my iOS WKWebView app so that way when the user clicks on the button it takes them to the previous WKWebView page. I have found numerous tutorials on how to do this with IB but not with straight code. This is what I have so far:

原始ViewController.swift:

Original ViewController.swift:

import UIKit
import WebKit

class ViewController: UIViewController, WKNavigationDelegate {

    private var webView: WKWebView!

    let wv = WKWebView(frame: UIScreen.mainScreen().bounds) //needed for working webview

    self.webView = WKWebView(frame: frame)
    self.webView.navigationDelegate = self

    func rightbutton(text: String, action: Selector) {
        let rightButton = UIBarButtonItem(title: text, style: .Plain, target: self, action: action)
        self.navigationItem.rightBarButtonItem = rightButton
    }

    func action() {
        if self.webView.canGoBack {
            print ("Can go back")
            self.webView.goBack()
            self.webView.reload()

        } else {
            print ( "Can't go back")
        }
    }


    override func viewDidLoad() {
        super.viewDidLoad()
        guard let url =  NSURL(string: "http://communionchapelefca.org/app-home") else { return }
        wv.navigationDelegate = self
        wv.loadRequest(NSURLRequest(URL: url))
        view.addSubview(wv)


        webView.goBack()
        webView.reload()



        prefButton()
        //backButton()

        NSNotificationCenter.defaultCenter().addObserver(self,
            selector: "receiveNotification:",
            name: "BeaconServiceRegionEnter",
            object: nil)

        NSNotificationCenter.defaultCenter().addObserver(self,
            selector: "receiveNotification:",
            name: "BeaconServiceRegionUpdate",
            object: nil)

        NSNotificationCenter.defaultCenter().addObserver(self,
            selector: "receiveNotification:",
            name: "BeaconServiceRegionExit",
            object: nil)

    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

    func prefButton () {
        let image = UIImage(named: "icon-pref128") as UIImage?
        let button   = UIButton(type: UIButtonType.Custom) as UIButton
        let screenSize: CGRect = UIScreen.mainScreen().bounds
        let screenWidth = screenSize.width
        let screenHeight = screenSize.height

        button.frame = CGRectMake(screenWidth * 0.85, screenHeight * 0.90, 56, 56) // (X, Y, Height, Width)
        button.setImage(image, forState: .Normal)
        button.addTarget(self, action: "buttonClicked:", forControlEvents:.TouchUpInside)
        self.view.addSubview(button)
    }

    func buttonClicked(sender:UIButton)
    {
        UIApplication.sharedApplication().openURL(NSURL(string: UIApplicationOpenSettingsURLString)!)
    }

    func receiveNotification(notification: NSNotification) {
        print(notification.userInfo)
    }

    func webView(webView: WKWebView, decidePolicyForNavigationAction navigationAction: WKNavigationAction, decisionHandler: (WKNavigationActionPolicy) -> Void) {
        if navigationAction.navigationType == .LinkActivated  {
            if let newURL = navigationAction.request.URL,
                host = newURL.host where !host.containsString("communionchapelefca.org") &&
                    UIApplication.sharedApplication().canOpenURL(newURL) {
                        if UIApplication.sharedApplication().openURL(newURL) {
                            print(newURL)
                            print("Redirected to browser. No need to open it locally")
                            decisionHandler(.Cancel)
                        } else {
                            print("browser can not url. allow it to open locally")
                            decisionHandler(.Allow)
                        }
            } else {
                print("Open it locally")
                decisionHandler(.Allow)
            }
        } else {
            print("not a user click")
            decisionHandler(.Allow)
        }
    }

}

有什么建议吗?预先感谢.

Any suggestions? Thanks in advance.

附加了整个ViewController，而不是代码段.

attached entire ViewController rather than snippet of code.

k8mil的回答很接近，因为他的回答没有加载初始URL.以下是他的回答中唯一的调整:

Answer by k8mil was close as his answer didnt load the initial URL. Below is the only adjustment from his answer:

private func createWebView() {
        guard let url = NSURL(string: "http://communionchapelefca.org/app-home") else { return }
        let frame  = UIScreen.mainScreen().bounds // or different frame created using CGRectMake(x,y,width,height)
        self.webView = WKWebView(frame: frame)
        self.webView.navigationDelegate = self
        self.webView.loadRequest(NSURLRequest(URL: url))
        self.view.addSubview(self.webView)
    }

推荐答案

尝试在WKWebView实例上调用 webView.goBack()方法，而不是 WKWebView.goBack().同样，在 goBack()之后，您可以调用 webView.reload()方法以确保您位于正确的页面上.

Try to call webView.goBack() method on your WKWebView instance instead WKWebView.goBack(). Also after goBack() you can call a webView.reload() method to make sure you're on the correct page.

我稍微修改了您的代码

import UIKit
import WebKit

class ViewController: UIViewController, WKNavigationDelegate {

private var webView: WKWebView!

override func viewDidLoad() {
    super.viewDidLoad()
    guard let url = NSURL(string: "http://communionchapelefca.org/app-home") else {
        return
    }

    //create WebView and Back button
    createWebView()
    backButton()


    prefButton()


    NSNotificationCenter.defaultCenter().addObserver(self,
            selector: "receiveNotification:",
            name: "BeaconServiceRegionEnter",
            object: nil)

    NSNotificationCenter.defaultCenter().addObserver(self,
            selector: "receiveNotification:",
            name: "BeaconServiceRegionUpdate",
            object: nil)

    NSNotificationCenter.defaultCenter().addObserver(self,
            selector: "receiveNotification:",
            name: "BeaconServiceRegionExit",
            object: nil)

}


private func createWebView() {
    let frame  = UIScreen.mainScreen().bounds // or different frame created using CGRectMake(x,y,width,height)
    self.webView = WKWebView(frame: frame)
    self.webView.navigationDelegate = self
    self.view.addSubview(self.webView)
}

func addBackButton(text: String, action: Selector) {
    //this function will add Button on your navigation bar e

    let rightButton = UIBarButtonItem(title: text, style: .Plain, target: self, action: action)
    self.navigationItem.rightBarButtonItem = rightButton
}


override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

func prefButton() {
    let image = UIImage(named: "icon-pref128") as UIImage?
    let button = UIButton(type: UIButtonType.Custom) as UIButton
    let screenSize: CGRect = UIScreen.mainScreen().bounds
    let screenWidth = screenSize.width
    let screenHeight = screenSize.height

    button.frame = CGRectMake(screenWidth * 0.85, screenHeight * 0.90, 56, 56) // (X, Y, Height, Width)
    button.setImage(image, forState: .Normal)
    button.addTarget(self, action: "buttonClicked:", forControlEvents: .TouchUpInside)
    self.view.addSubview(button)
}

func backButton() {
    let image = UIImage(named: "icon-back") as UIImage?
    let button = UIButton(type: UIButtonType.Custom) as UIButton
    let screenSize: CGRect = UIScreen.mainScreen().bounds
    let screenWidth = screenSize.width
    let screenHeight = screenSize.height

    button.frame = CGRectMake(screenWidth * 0.85, screenHeight * 0.90, 56, 56) // (X, Y, Height, Width)
    button.setImage(image, forState: .Normal)
    button.addTarget(self, action: "customGoBack:", forControlEvents: .TouchUpInside)
    self.view.addSubview(button)
}

func customGoBack(sender: UIButton) {
    if self.webView.canGoBack {
        print("Can go back")
        self.webView.goBack()
        self.webView.reload()
    } else {
        print("Can't go back")
    }
}

func buttonClicked(sender: UIButton) {
    UIApplication.sharedApplication().openURL(NSURL(string: UIApplicationOpenSettingsURLString)!)
}

func receiveNotification(notification: NSNotification) {
    print(notification.userInfo)
}

func webView(webView: WKWebView, decidePolicyForNavigationAction navigationAction: WKNavigationAction, decisionHandler: (WKNavigationActionPolicy) -> Void) {
    if navigationAction.navigationType == .LinkActivated {
        if let newURL = navigationAction.request.URL,
        host = newURL.host where !host.containsString("communionchapelefca.org") &&
                UIApplication.sharedApplication().canOpenURL(newURL) {
            if UIApplication.sharedApplication().openURL(newURL) {
                print(newURL)
                print("Redirected to browser. No need to open it locally")
                decisionHandler(.Cancel)
            } else {
                print("browser can not url. allow it to open locally")
                decisionHandler(.Allow)
            }
        } else {
            print("Open it locally")
            decisionHandler(.Allow)
        }
    } else {
        print("not a user click")
        decisionHandler(.Allow)
    }
}

}

另外，您不需要处理WKWebView的另一个实例，因为您先前已经在:

Also you don't neeed another instance of WKWebView because you have declared previously in :

private var webView:WKWebView！

所以没有必要:

wv.navigationDelegate = self
wv.loadRequest(NSURLRequest(URL: url))  
view.addSubview(wv)

对我来说有效.

希望这会对您有所帮助:)

Hope this will help you :)

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