bridge.callHandler('ObjC Echo', {'key':'value'}, function responseCallback(responseData) { console.log("JS received response:", responseData) })

function callHandler(handlerName, data, responseCallback) { if (arguments.length == 2 && typeof data =https://www.it610.com/article/='function') { responseCallback = data; data = null; } _doSend({ handlerName:handlerName, data:data }, responseCallback); }

function _doSend(message, responseCallback) { if (responseCallback) { var callbackId = 'cb_'+(uniqueId++)+'_'+new Date().getTime(); responseCallbacks[callbackId] = responseCallback; message['callbackId'] = callbackId; } sendMessageQueue.push(message); messagingIframe.src = https://www.it610.com/article/CUSTOM_PROTOCOL_SCHEME +'://' + QUEUE_HAS_MESSAGE; }

// 代码有改动 - (void)webView:(WKWebView *)webView decidePolicyForNavigationAction:(WKNavigationAction *)navigationAction decisionHandler:(void (^)(WKNavigationActionPolicy))decisionHandler { [self WKFlushMessageQueue]; } - (void)WKFlushMessageQueue { [_webView evaluateJavaScript:[_base webViewJavascriptFetchQueyCommand] completionHandler:^(NSString* result, NSError* error) { if (error != nil) { NSLog(@"WebViewJavascriptBridge: WARNING: Error when trying to fetch data from WKWebView: %@", error); } [_base flushMessageQueue:result]; }]; }

// oc - (NSString *)webViewJavascriptFetchQueyCommand { return @"WebViewJavascriptBridge._fetchQueue(); "; }

// js function _fetchQueue() { var messageQueueString = JSON.stringify(sendMessageQueue); sendMessageQueue = []; return messageQueueString; }

- (void)flushMessageQueue:(NSString *)messageQueueString{ // 代码有删减// 先返序列化出messages 对象 id messages = [self _deserializeMessageJSON:messageQueueString]; for (WVJBMessage* message in messages) { if (![message isKindOfClass:[WVJBMessage class]]) { NSLog(@"WebViewJavascriptBridge: WARNING: Invalid %@ received: %@", [message class], message); continue; } [self _log:@"RCVD" json:message]; NSString* responseId = message[@"responseId"]; if (responseId) { // OC 调用 JS 时回调使用 WVJBResponseCallback responseCallback = _responseCallbacks[responseId]; responseCallback(message[@"responseData"]); [self.responseCallbacks removeObjectForKey:responseId]; } else { WVJBResponseCallback responseCallback = NULL; NSString* callbackId = message[@"callbackId"]; if (callbackId) { responseCallback = ^(id responseData) { if (responseData =https://www.it610.com/article/= nil) { responseData = [NSNull null]; }WVJBMessage* msg = @{ @"responseId":callbackId, @"responseData":responseData }; [self _queueMessage:msg]; }; } else { responseCallback = ^(id ignoreResponseData) { // Do nothing }; }WVJBHandler handler = self.messageHandlers[message[@"handlerName"]]; if (!handler) { NSLog(@"WVJBNoHandlerException, No handler for message from JS: %@", message); continue; }handler(message[@"data"], responseCallback); } } }

responseCallback = ^(id responseData) { if (responseData =https://www.it610.com/article/= nil) { responseData = [NSNull null]; }WVJBMessage* msg = @{ @"responseId":callbackId, @"responseData":responseData }; [self _queueMessage:msg]; }

function _doDispatchMessageFromObjC() { // 代码有删减 var message = JSON.parse(messageJSON); var responseCallback; if (message.responseId) { responseCallback = responseCallbacks[message.responseId]; if (!responseCallback) { return; } responseCallback(message.responseData); delete responseCallbacks[message.responseId]; } }

bridge.callHandler('ObjC Echo', {'key':'value'}, function responseCallback(responseData) { 至此我们就能在这里愉快的打印responseData })

[weakSelf.bridge callHandler:@"jsCallBack" data:jsonParameter responseCallback:^(id responseData) { }];

- (void)sendData:(id)data responseCallback:(WVJBResponseCallback)responseCallback handlerName:(NSString*)handlerName { NSMutableDictionary* message = [NSMutableDictionary dictionary]; if (data) { message[@"data"] = data; }if (responseCallback) { NSString* callbackId = [NSString stringWithFormat:@"objc_cb_%ld", ++_uniqueId]; self.responseCallbacks[callbackId] = [responseCallback copy]; message[@"callbackId"] = callbackId; }if (handlerName) { message[@"handlerName"] = handlerName; } [self _queueMessage:message]; }

function _doDispatchMessageFromObjC() { // 代码有删减 var message = JSON.parse(messageJSON); var messageHandler; var responseCallback; if (message.callbackId) { var callbackResponseId = message.callbackId; responseCallback = function(responseData) { _doSend({ handlerName:message.handlerName, responseId:callbackResponseId, responseData:responseData }); }; }var handler = messageHandlers[message.handlerName]; if (!handler) { console.log("WebViewJavascriptBridge: WARNING: no handler for message from ObjC:", message); } else { handler(message.data, responseCallback); } } }

bridge.registerHandler('JS Echo', function(data, responseCallback) { console.log("JS Echo called with:", data) responseCallback(data) })

responseCallback = function(responseData) { _doSend({ handlerName:message.handlerName, responseId:callbackResponseId, responseData:responseData }); }; }

- (void)flushMessageQueue:(NSString *)messageQueueString{ // 代码有删减 // 反序列化 id messages = [self _deserializeMessageJSON:messageQueueString]; for (WVJBMessage* message in messages) { if (![message isKindOfClass:[WVJBMessage class]]) { NSLog(@"WebViewJavascriptBridge: WARNING: Invalid %@ received: %@", [message class], message); continue; } [self _log:@"RCVD" json:message]; NSString* responseId = message[@"responseId"]; if (responseId) { WVJBResponseCallback responseCallback = _responseCallbacks[responseId]; responseCallback(message[@"responseData"]); [self.responseCallbacks removeObjectForKey:responseId]; } } }

• 本文大多采用代码片段来描述代码执行过程，想要了解真正的精髓还需仔细研究源码
• 文章写的比较仓促，文中难免有误，欢迎发现错误的同学批评指正。

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