swift5调用H5页面，H5调用swift5，参数传递

之前的webview等组件官方已经不支持了，文档中都已经标记废弃了,现在要使用WKWebView，官方说这个新的组件性能更高更安全，建议大家都转这个来使用。具体步骤如下:
1.首先WKWebView所在controller一定要继承WKNavigationDelegate ，WKScriptMessageHandler,xcode会提示你实现扩展方法,一个是webView一个是userContentController,当然还有其他方法可以查阅文档
接下来直接给出代码然后再进行说明

class UserCenterViewController: UIViewController, WKNavigationDelegate, WKScriptMessageHandler {
    lazy var webView: WKWebView = {
        
        let preferences = WKPreferences()
        //preferences.javaScriptEnabled = true
        let configuration = WKWebViewConfiguration()
        configuration.preferences = preferences
        configuration.userContentController = WKUserContentController()
        //注册changePwdByJS这个函数,让js调用
        configuration.userContentController.add(self, name: "changePwdByJS")
        configuration.userContentController.add(self, name: "getUserInfoByJS")
        var webView = WKWebView(frame: CGRect(x: 0, y: 0, width: view.frame.width, height: view.frame.height), configuration: configuration)
        webView.scrollView.bounces = true
        webView.scrollView.alwaysBounceVertical = true
        webView.navigationDelegate = self
        return webView
    }()
    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = .white
        automaticallyAdjustsScrollViewInsets = false
        view.addSubview(webView)
        //加载H5页面
        let myURL = URL(string: H5_SERVER + USER_CENTER)
        let myRequest = URLRequest(url: myURL!)
        webView.load(myRequest)
    }
    @objc private func goBackMenu() {
        webView.evaluateJavaScript("goBackMenuByIOS()") { (result, err) in
//            print("goBackMenuByIOS")
//            print(result)
//            print(err)
        }
    }  
  func webView(_ webView: WKWebView, didFinish navigation: WKNavigation!) {
        //web加载好了才有左边按钮
        leftBtton = UIButton()
        leftBtton.setImage(UIImage(name:"back"), for: .normal)
        leftBtton.addTarget(self, action: #selector(goBackMenu), for: .touchUpInside)
        self.navigationItem.leftBarButtonItem = UIBarButtonItem(customView: leftBtton)
            
    }
    func userContentController(_ userContentController: WKUserContentController, didReceive message: WKScriptMessage) {
        
        print("-------------" + message.name)
        
        if message.name == "changePwdByJS" {
           
            print(message.body as! [String])
            
        }else if message.name == "getUserInfoByJS" {
            //进入个人中心的时候,H5调我获取下用户的数据
            let user = UserDefaults.standard
            let json = JSON([
                USER_NAME: user.string(forKey: USER_NAME) as Any,
                USER_ID: user.string(forKey: USER_ID) as Any,
            ])
            
            let s: String = json.rawString()!
            webView.evaluateJavaScript("getUserInfoByIOS(" + s + ")", completionHandler: nil)
        }
    }
}

2.swift调用js,切记一定要等加载完了才能调用,这个带有didFinsh参数的webView被自动调用的时候就是加载完页面的时候,假如说有个按钮是要点击下弹出个网页，这个时候可以在webView这个方法中初始化这个按钮并为它加事件,因为这样可以保证这个按钮被点击的时候网页被加载完了，这样就不会报错说js未加载完

    @objc private func goBackMenu() {
        webView.evaluateJavaScript("goBackMenuByIOS()") { (result, err) in
//            print("goBackMenuByIOS")
//            print(result)
//            print(err)
        }
    }  
  func webView(_ webView: WKWebView, didFinish navigation: WKNavigation!) {
        //web加载好了才有左边按钮
        leftBtton = UIButton()
        leftBtton.setImage(UIImage(name:"back"), for: .normal)
        leftBtton.addTarget(self, action: #selector(goBackMenu), for: .touchUpInside)
        self.navigationItem.leftBarButtonItem = UIBarButtonItem(customView: leftBtton)
            
    }

2.js调用swift,上面代码样例中注册了两个函数changePwdByJS,getUserInfoByJS,这两个函数可以被JS调用,具体就是下面这段代码,没啥好解释的应该都能明白

    func userContentController(_ userContentController: WKUserContentController, didReceive message: WKScriptMessage) {
        
        print("-------------" + message.name)
        
        if message.name == "changePwdByJS" {
           
            print(message.body as! [String])
            
        }else if message.name == "getUserInfoByJS" {
         
            let user = UserDefaults.standard
            let json = JSON([
                USER_NAME: user.string(forKey: USER_NAME) as Any,
                USER_ID: user.string(forKey: USER_ID) as Any,
            ])
            
            let s: String = json.rawString()!
            webView.evaluateJavaScript("getUserInfoByIOS(" + s + ")", completionHandler: nil)
        }
    }