译者:@coderyi9
本文翻译自Marcus Westin的开源框架WebViewJavascriptBridge的readme,英文原文链接https://github.com/marcuswestin/WebViewJavascriptBridge.
WebViewJavascriptBridge是Obj-C和JavaScript通过UIWebViews/WebViews互通消息的一个iOS/OSX的桥梁. 如果你喜欢WebViewJavascriptBridge,你可能也想check outWebViewProxy.
Obj-C和JavaScript原理简单说一下,Obj-C调用JavaScript很简单,可以通过webview的stringByEvaluatingJavaScriptFromString:方法调用JavaScript代码;JavaScript调用Obj-C,则是通过web view的代理方法shouldStartLoadWithRequest:来接收JavaScript的网络请求从而实现调用。
正在使用WebViewJavascriptBridge的项目
有很多的公司和项目在使用WebViewJavascriptBridge.这个列表不完整,你可以随意添加.
安装& 例子 (iOS & OSX)
首先打开Example Apps文件夹.打开iOS或者OSX的工程然后点击运行.
在你自己的工程中用WebViewJavascriptBridge:
1) 拖动 WebViewJavascriptBridge 文件夹到你的工程中.
在出现的对话框中, 取消 (我觉得应该是选中)”Copy items into destination group’s folder” 并且 选择 “Create groups for any folders”
2) 引入头文件并且申明一个属性:
1 2 3 | #import "WebViewJavascriptBridge.h" ... @property WebViewJavascriptBridge* bridge; |
3) 实例化WebViewJavascriptBridge并且带上一个UIWebView (iOS)或者WebView (OSX):
1 2 3 4 | self.bridge = [WebViewJavascriptBridge bridgeForWebView:webView handler:^(id data, WVJBResponseCallback responseCallback) { NSLog(@ "Received message from javascript: %@" , data); responseCallback(@ "Right back atcha" ); }]; |
4) 首先从ObjC到javascript发送一些消息:
1 2 3 4 5 | [self.bridge send:@ "Well hello there" ]; [self.bridge send:[NSDictionary dictionaryWithObject:@ "Foo" forKey:@ "Bar" ]]; [self.bridge send:@ "Give me a response, will you?" responseCallback:^(id responseData) { NSLog(@ "ObjC got its response! %@" , responseData); }]; |
5) 然后,看看javascript这边:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 | function connectWebViewJavascriptBridge(callback) { if (window.WebViewJavascriptBridge) { callback(WebViewJavascriptBridge) } else { document.addEventListener( 'WebViewJavascriptBridgeReady' , function () { callback(WebViewJavascriptBridge) }, false ) } } connectWebViewJavascriptBridge( function (bridge) { /* Init your app here */ bridge.init( function (message, responseCallback) { alert( 'Received message: ' + message) if (responseCallback) { responseCallback( "Right back atcha" ) } }) bridge.send( 'Hello from the javascript' ) bridge.send( 'Please respond to this' , function responseCallback(responseData) { console.log( "Javascript got its response" , responseData) }) }) |
Contributors & Forks
Contributors: https://github.com/marcuswestin/WebViewJavascriptBridge/graphs/contributors
Forks: https://github.com/marcuswestin/WebViewJavascriptBridge/network/members
API 参考
ObjC API
[WebViewJavascriptBridge bridgeForWebView: (UIWebView/WebView*)webview handler:(WVJBHandler)handler]
[WebViewJavascriptBridge bridgeForWebView:
(UIWebView/WebView*)webview webViewDelegate:
(UIWebViewDelegate*)webViewDelegate handler:(WVJBHandler)handler]
给web view创建一个javascript的桥梁.
假如javascript需要一个反馈,那么 WVJBResponseCallback 不能为 nil .
当然,通过 webViewDelegate:(UIWebViewDelegate*)webViewDelegate 你可以得到web view的生命周期事件.
例子:
1 2 3 4 5 6 7 | [WebViewJavascriptBridge bridgeForWebView:webView handler:^(id data, WVJBResponseCallback responseCallback) { NSLog(@ "Received message from javascript: %@" , data); if (responseCallback) { responseCallback(@ "Right back atcha" ); } }] [WebViewJavascriptBridge bridgeForWebView:webView webViewDelegate:self handler:^(id data, WVJBResponseCallback responseCallback) { /* ... */ }]; |
[bridge send:(id)data]
[bridge send:(id)data responseCallback:(WVJBResponseCallback)responseCallback]
发送一个消息给javascript. 并且在发送消息成功后可以通过 responseCallback block做出一 些反应.
例子:
1 2 3 4 5 | [self.bridge send:@ "Hi" ]; [self.bridge send:[NSDictionary dictionaryWithObject:@ "Foo" forKey:@ "Bar" ]]; [self.bridge send:@ "I expect a response!" responseCallback:^(id responseData) { NSLog(@ "Got response! %@" , responseData); }]; |
[bridge registerHandler:(NSString*)handlerName handler: (WVJBHandler)handler]
注册一个叫做 handlerName 的handler. javascript能够通过 WebViewJavascriptBridge.callHandler(“handlerName”) 调起这个handler.
例子:
1 2 3 | [self.bridge registerHandler:@ "getScreenHeight" handler:^(id data, WVJBResponseCallback responseCallback) { responseCallback([NSNumber numberWithInt:[UIScreen mainScreen].bounds.size.height]); }]; |
[bridge callHandler:(NSString*)handlerName data:(id)data]
[bridge callHandler:(NSString*)handlerName data:(id)data responseCallback:(WVJBResponseCallback)callback]
调起javascript叫做 handlerName的handler. 在调用 handler成功后可以通过responseCallback block做出反应.
例子:
1 2 3 4 | [self.bridge callHandler:@ "showAlert" data:@ "Hi from ObjC to JS!" ]; [self.bridge callHandler:@ "getCurrentPageUrl" data:nil responseCallback:^(id responseData) { NSLog(@ "Current UIWebView page URL is: %@" , responseData); }]; |
定义 bundle
WebViewJavascriptBridge 要求 WebViewJavascriptBridge.js.txt 文件嵌入到web view来创建一个在JS这边的桥梁.标准的实现是用 mainBundle 找到这个文件.如果你建立一个 静态库并且你把这个文件放在其他地方,你可以用下面的方法找 WebViewJavascriptBridge.js.txt 文件:
[WebViewJavascriptBridge bridgeForWebView:
(UIWebView/WebView*)webView webViewDelegate:
(UIWebViewDelegate*)webViewDelegate handler:(WVJBHandler)handler
resourceBundle:(NSBundle*)bundle
例子:
1 2 3 4 5 6 7 | [WebViewJavascriptBridge bridgeForWebView:_webView webViewDelegate:self handler:^(id data, WVJBResponseCallback responseCallback) { NSLog(@ "Received message from javascript: %@" , data); } resourceBundle:[NSBundle bundleWithURL:[[NSBundle mainBundle] URLForResource:@ "ResourcesBundle" withExtension:@ "bundle" ]] ]; |
Javascript API
document.addEventListener(‘WebViewJavascriptBridgeReady’,
function onBridgeReady(event) { … }, false)
一直等待 WebViewJavascriptBridgeReady DOM 事件.
例子:
1 2 3 4 | document.addEventListener( 'WebViewJavascriptBridgeReady' , function (event) { var bridge = event.bridge // Start using the bridge }, false ) |
bridge.init(function messageHandler(data, response) { … })
初始化这个桥. 这会调起 ‘WebViewJavascriptBridgeReady’ 的事件handler.
这个 messageHandler 函数会接收通过ObjC的 [bridge send:(id)data] 和 [bridge send:(id)data responseCallback:(WVJBResponseCallback)responseCallback] 方法 发送的所有消息.
如果ObjC发送消息时有WVJBResponseCallback block,那么可以通过response对象发送消息.
例子:
1 2 3 4 5 6 | bridge.init( function (data, responseCallback) { alert( "Got data " + JSON.stringify(data)) if (responseCallback) { responseCallback( "Right back atcha!" ) } }) |
bridge.send(“Hi there!”)
bridge.send({ Foo:”Bar” })
bridge.send(data, function responseCallback(responseData) { …
})
给ObjC发送消息. 在发送成功后可以通过 responseCallback 函数做出反应.
例子:
1 2 3 4 | bridge.send( "Hi there!" ) bridge.send( "Hi there!" , function (responseData) { alert( "I got a response! " +JSON.stringify(responseData)) }) |
bridge.registerHandler(“handlerName”, function(responseData) { … })
注册一个叫做 handlerName 的handler. ObjC能够通过 [bridge callHandler:”handlerName” data:@”Foo”] 和 [bridge callHandler:”handlerName” data:@”Foo” responseCallback:^(id responseData) { … }] 两个方法调起这个handler.
例子:
1 2 3 4 | bridge.registerHandler( "showAlert" , function (data) { alert(data) }) bridge.registerHandler( "getCurrentPageUrl" , function (data, responseCallback) { responseCallback(document.location.toString()) }) |
iOS4 支持 (包括 JSONKit)
注:iOS4支持尚未在V2 +测试.
WebViewJavascriptBridge 默认使用 NSJSONSerialization .如果你需要iOS 4的支持,你可以用JSONKit,并且增加 USE_JSONKIT 的预处理宏到你的工程中.
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