由于H5的灵活多变，动态可配的特点，也为了避免冗长 的审核周期，H5页面在app上的重要性正日益突显。
iOS应用于H5交互的控件主要是UIWebView及WKWebView
WKWebView是14年随iOS8推出的，很好的解决了UIWebView加载速度慢，内存占用大的问题
WebViewJavaScriptBridge是一款轻量级的框架，使用它结合wkwebview能十分方便的实现源生与H5的交互
webviewJavaScrptBridge的基本使用
1.初始化需bind视图 [WebViewJavaScriptBridge bridgeForWebView:]
2.设置代理 [self.bridge setWebViewDelegate:self]
3.注册方法
[self.bridge registerHandler:@"click" handler:^(id data, WVJBResponseCallback responseCallback) {
NSDictionary *dic = (NSDictionary *)data;
[weakSelf responseJSWithData:(NSDictionary *)dic];
}];
click是方法名，handler是H5发起调用后传回的回调，该闭包第一个H5页面传递过来的参数，第二个是callBack对象
4.调用方法
[self.bridge callHandler:event data:data responseCallback:^(id responseData) {
NSLog(@"responseData:%@",responseData);
}];
event是方法名，源生直接发起回调，data是传递的参数，callBack是h5收到事件后传回的回调
webviewJavaScriptBridge的精髓就是方法3，4的交替使用，使得源生调h5,h5调源生变的异常简单，两者之间的链接仅仅靠一个方法名，收方register后，发起方callHandler就能实现一条消息的有效传递，具体实现细节可细究其源码 webviewJavaScriptBridge
现在来探究下H5端如何使用bridge注册及发起事件
/// 配置bridgefunction setupWebViewJavascriptBridge(callback) { ???????if (window.WebViewJavascriptBridge) { return callback(WebViewJavascriptBridge); } ???????if (window.WVJBCallbacks) { return window.WVJBCallbacks.push(callback); } ???????window.WVJBCallbacks = [callback]; ???????var WVJBIframe = document.createElement(‘iframe‘); ???????WVJBIframe.style.display = ‘none‘; ???????WVJBIframe.src = ‘https://__bridge_loaded__‘; ???????document.documentElement.appendChild(WVJBIframe); ???????setTimeout(function() { document.documentElement.removeChild(WVJBIframe) }, 0) ???}/// callHandler ???data为H5传递参数setupWebViewJavascriptBridge(function (bridge) { ???????????let data = {‘title‘: title} ???????????bridge.callHandler(‘setTitle‘, data) ???????})/// registerHandler ???data为源生传递参数bridge.registerHandler("result", function (data, responseCallback) { ???????????result(data[‘opType‘], data[‘code‘], data[‘msg‘]) ???????})可见在H5端使用bridge完成消息的收发页十分方便。webviewJavaScriptCoreBridge的配置，是在H5页面生成一个iframe节点，传递消息时插入这个节点，结束后移除这个节点，以此来实现源生到H5的一次消息传递。
WKNavigationDelegate 使用wkwebview进行一次网络请求中的各种事件回调
WKUIDelegate 主要用于处理H5中的alert弹窗事件
-runJavaScriptAlertPanelWithMessage:
UIWebView，尽管该视图已经被WKWebview取代，但市面上大多数应用框架仍然使用的是webview，并且其更接近底层，具有深究价值
UIWebview通常是通过拦截request，根据指定url中的参数，来实现H5端事件的调用
func webView(_ webView: UIWebView, shouldStartLoadWith request: URLRequest, navigationType: UIWebViewNavigationType) -> Bool ???{ ???????let ?absoluteString = request.url!.absoluteStringif (!absoluteString.contain(prefix)) {return true}else {
// do somethingreturn false} ???}返回false则拦截请求，截取url中所带参数，根据需求做相应处理。通常为封装方法间的调用，会插入一段js代码。
override func webViewDidStartLoad(_ webView: UIWebView) { ???????super.webViewDidStartLoad(webView) ???????????????/// 尽可能在较早的时间点插入该js代码 ???????writtenJSApi(webView: webView) ???}func writtenJSApi(webView:UIWebView) { ???????if ?let filePath:String = Bundle.main.path(forResource: "jsapi", ofType: "js"){ ???????????if let jsStr = try? NSString(contentsOfFile: filePath, encoding: String.Encoding.utf8.rawValue){ ???????????????webView.stringByEvaluatingJavaScript(from: jsStr as String) ???????????} ???????} ???}js主要代码
// 异步 window.JSApi.asyncInvoke = function (apiname, pramaJsonString, callbackapi) { var apiPath = "https://asyncjsapi.com/" + encodeURIComponent(apiname + window.JSApi.pramaSplit + pramaJsonString + window.JSApi.pramaSplit + callbackapi); var iframe = document.createElement("iframe"); iframe.setAttribute("src", apiPath); document.documentElement.appendChild(iframe); iframe.parentNode.removeChild(iframe); iframe = null; } ?// 同步 window.JSApi.syncInvoke = function (apiname, pramaJsonString) { var apiPath = "https://syncjsapi.com/" + encodeURIComponent(apiname + window.JSApi.pramaSplit + pramaJsonString ); var request = new XMLHttpRequest(); if (request == null) { return { code: 1, errorMsg: "not support XMLHttpRequest", data: null }; } ?var responseText = "" ?request.onreadystatechange = function () { // alert("stateChange"+request.readyState+","+request.status) if (request.readyState == 4 && request.status == 200) { responseText = request.responseText; } else { responseText = "" } // alert(responseText) }; // alert(apiname+" ?2 ?request open ???"+apiPath); request.open("GET", apiPath, false); request.send(null); ?console.log(responseText) ?return responseText } })();可以看出，异步方法依然是在页面创建iframe，先插入后删除的方式；同步方法是利用ajax，创建了一个http请求，并监听request的状态，当status为200时，返回信息给H5。同步方法的拦截是在urlProtocol里面
class JsApiURLProtocol: URLProtocol, URLSessionDataDelegate, URLSessionTaskDelegate {override class func canInit(with request: URLRequest) -> Bool {if let strUrl:String = request.url?.absoluteString ???????{ ???????????if JsApiHelper.isSyncNativeApi(urlString: strUrl) { ???????????????return true ???????????} ???????}else { ???????return false ???????}}override func startLoading() { ???????let strUrl:String! = request.url!.absoluteString ???????if JsApiHelper.isSyncNativeApi(urlString: strUrl) { ???????????// 调用同步jsapi ???????????let result: NSString = JsApiHelper.syncInvoke(urlString: strUrl! as NSString) as NSString ???????????let resultData: NSData = result.data(using: String.Encoding.utf8.rawValue)! as NSData ???????????var headerFields: [NSObject : AnyObject]? = [NSObject : AnyObject]() ???????????headerFields?.updateValue("*" as AnyObject, forKey: "Access-Control-Allow-Origin" as NSObject) ???????????????????????let response: HTTPURLResponse = HTTPURLResponse(url: self.request.url!, statusCode: 200, httpVersion: "HTTP/1.1", headerFields: headerFields as? [String:String])! ???????????self.client!.urlProtocol(self, didReceive: response, cacheStoragePolicy: .notAllowed) ???????????self.client!.urlProtocol(self, didLoad: resultData as Data) ???????????self.client!.urlProtocolDidFinishLoading(self) ???????} ???}}caninit方法中return true表示进行请求，否则拦截请求。startLoading方法中创建相应的response返回给js中的request，注意finishLoading，否则容易造成死循环。
UIWebview调用H5就相当简单了，一句代码搞定
webView.stringByEvaluatingJavaScript(from: "javascript:window.goBack()");
webview和H5交互
原文地址：https://www.cnblogs.com/xiaoerheiwatu/p/10004409.html