原文地址:www.cocoachina.com/ios/20150629/12248.html?
譯者：@coderyi9
本文翻譯自Marcus Westin的開源框架WebViewJavascriptBridge的readme,英文原文鏈接https://github.com/marcuswestin/WebViewJavascriptBridge.
WebViewJavascriptBridge是Obj-C和JavaScript通過UIWebViews/WebViews互通消息的一個iOS/OSX的橋梁. 如果你喜歡WebViewJavascriptBridge,你可能也想check outWebViewProxy.
Obj-C和JavaScript原理簡單說一下，Obj-C調用JavaScript很簡單，可以通過webview的stringByEvaluatingJavaScriptFromString:方法調用JavaScript代碼；JavaScript調用Obj-C，則是通過web
view的代理方法shouldStartLoadWithRequest：來接收JavaScript的網絡請求從而實現調用。
正在使用WebViewJavascriptBridge的項目
有很多的公司和項目在使用WebViewJavascriptBridge.這個列表不完整,你可以隨意添加.
Flutterby Labs
JD Media’s鼎盛中華
Dojo4’sImbed
安裝& 例子 (iOS & OSX)
首先打開Example Apps文件夾.打開iOS或者OSX的工程然后點擊運行.
在你自己的工程中用WebViewJavascriptBridge:
1) 拖動 WebViewJavascriptBridge 文件夾到你的工程中.
在出現的對話框中, 取消 (我覺得應該是選中)”Copy items into destination group’s folder” 并且 選擇 “Create groups for any folders”
2) 引入頭文件并且申明一個屬性:
1
2
3#import?"WebViewJavascriptBridge.h"
...
@property?WebViewJavascriptBridge*?bridge;
3) 實例化WebViewJavascriptBridge并且帶上一個UIWebView (iOS)或者WebView (OSX):
1
2
3
4self.bridge?=?[WebViewJavascriptBridge?bridgeForWebView:webView?handler:^(id?data,?WVJBResponseCallback?responseCallback)?{
NSLog(@"Received?message?from?javascript:?%@",?data);
responseCallback(@"Right?back?atcha");
}];
4) 首先從ObjC到javascript發送一些消息:
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這邊:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22functionconnectWebViewJavascriptBridge(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',functionresponseCallback(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 參考
ObjC API
[WebViewJavascriptBridge bridgeForWebView: (UIWebView/WebView*)webview handler:(WVJBHandler)handler]
[WebViewJavascriptBridge bridgeForWebView:
(UIWebView/WebView*)webview webViewDelegate:
(UIWebViewDelegate*)webViewDelegate handler:(WVJBHandler)handler]
給web view創建一個javascript的橋梁.
假如javascript需要一個反饋,那么 WVJBResponseCallback 不能為 nil .
當然,通過 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]
發送一個消息給javascript. 并且在發送消息成功后可以通過 responseCallback block做出一 些反應.
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]
注冊一個叫做 handlerName 的handler. javascript能夠通過 WebViewJavascriptBridge.callHandler(“handlerName”) 調起這個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]
調起javascript叫做 handlerName的handler. 在調用 handler成功后可以通過responseCallback block做出反應.
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);
}];
定義 bundle
WebViewJavascriptBridge
要求 WebViewJavascriptBridge.js.txt 文件嵌入到web view來創建一個在JS這邊的橋梁.標準的實現是用
mainBundle 找到這個文件.如果你建立一個 靜態庫并且你把這個文件放在其他地方,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
4document.addEventListener('WebViewJavascriptBridgeReady',function(event)?{
varbridge?=?event.bridge
//?Start?using?the?bridge
},false)
bridge.init(function messageHandler(data, response) { … })
初始化這個橋. 這會調起 ‘WebViewJavascriptBridgeReady’ 的事件handler.
這個
messageHandler 函數會接收通過ObjC的 [bridge send:(id)data] 和 [bridge
send:(id)data responseCallback:(WVJBResponseCallback)responseCallback]
方法 發送的所有消息.
如果ObjC發送消息時有WVJBResponseCallback block,那么可以通過response對象發送消息.
例子:
1
2
3
4
5
6bridge.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) { …
})
給ObjC發送消息. 在發送成功后可以通過 responseCallback 函數做出反應.
例子:
1
2
3
4bridge.send("Hi?there!")
bridge.send("Hi?there!",function(responseData)?{
alert("I?got?a?response!?"+JSON.stringify(responseData))
})
bridge.registerHandler(“handlerName”, function(responseData) { … })
注冊一個叫做
handlerName 的handler. ObjC能夠通過 [bridge callHandler:”handlerName”
data:@”Foo”] 和 [bridge callHandler:”handlerName” data:@”Foo”
responseCallback:^(id responseData) { … }] 兩個方法調起這個handler.
例子:
1
2
3
4bridge.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 +測試.
WebViewJavascriptBridge 默認使用 NSJSONSerialization .如果你需要iOS 4的支持,你可以用JSONKit,并且增加 USE_JSONKIT 的預處理宏到你的工程中.
