目前很流行的库有WebviewJavaScriptBridge和OVGap，这两个库都是让webview与JS建立起一条桥梁，这样就可以相互通信了。
网上的教程几乎都是webview给调用JS，使用系统提供的方法，这是想学Easy就可以做到的，但是如果想让JS调用我们的原生的方法，那就不容易了，就需要一条桥梁，在JS响应的时候能回调OC的方法。这两个库都是可以满足我们的，但是在JS端需要添加对应的JS，对于前者，还需要把响应的方法放到桥梁内，如：
function connectWebViewJavascriptBridge(callback) {
if (window.WebViewJavascriptBridge) {
callback(WebViewJavascriptBridge)
} else {
document.addEventListener('WebViewJavascriptBridgeReady', function() {
callback(WebViewJavascriptBridge)
}, false)
}
}
connectWebViewJavascriptBridge(function(bridge) {
var uniqueId = 1
function log(message, data) {
var log = document.getElementById('log')
var el = document.createElement('div')
el.className = 'logLine'
el.innerHTML = uniqueId++ + '. ' + message + ':<br/>' + JSON.stringify(data)
if (log.children.length) { log.insertBefore(el, log.children[0]) }
else { log.appendChild(el) }
}
bridge.init(function(message, responseCallback) {
log('JS got a message', message)
var data = { 'Javascript Responds':'Wee!' }
log('JS responding with', data)
responseCallback(data)
})
bridge.registerHandler('testJavascriptHandler', function(data, responseCallback) {
log('ObjC called testJavascriptHandler with', data)
var responseData = { 'Javascript Says':'Right back atcha!' }
log('JS responding with', responseData)
responseCallback(responseData)
})
var button = document.getElementById('buttons').appendChild(document.createElement('button'))
button.innerHTML = 'Send message to ObjC'
button.onclick = function(e) {
e.preventDefault()
var data = 'Hello from JS button'
log('JS sending message', data)
bridge.send(data, function(responseData) {
log('JS got response', responseData)
})
}
document.body.appendChild(document.createElement('br'))
var callbackButton = document.getElementById('buttons').appendChild(document.createElement('button'))
callbackButton.innerHTML = 'Fire testObjcCallback'
callbackButton.onclick = function(e) {
e.preventDefault()
log('JS calling handler "testObjcCallback"')
bridge.callHandler('testObjcCallback', {'foo': 'bar'}, function(response) {
log('JS got response', response)
})
}
})
connectWebViewJavascriptBridge
这个方法是必须的，而响应要放在这个方法中，这样对安卓端可能会中影响，于是放弃了这个库的使用。
OVGap
使用这个库前，需要给HTML5中引入对方的脚本，叫ovgap.js，可到Github下载：
;(function() {
var require, define;
(function () {
var modules = {},
// Stack of moduleIds currently being built.
requireStack = [],
// Map of module ID -> index into requireStack of modules currently being built.
inProgressModules = {},
SEPERATOR = ".";
function build(module) {
var factory = module.factory,
localRequire = function (id) {
var resultantId = id;
//Its a relative path, so lop off the last portion and add the id (minus "./")
if (id.charAt(0) === ".") {
resultantId = module.id.slice(0, module.id.lastIndexOf(SEPERATOR)) + SEPERATOR + id.slice(2);
}
return require(resultantId);
};
module.exports = {};
delete module.factory;
factory(localRequire, module.exports, module);
return module.exports;
}
require = function (id) {
if (!modules[id]) {
throw "module " + id + " not found";
} else if (id in inProgressModules) {
var cycle = requireStack.slice(inProgressModules[id]).join('->') + '->' + id;
throw "Cycle in require graph: " + cycle;
}
if (modules[id].factory) {
try {
inProgressModules[id] = requireStack.length;
requireStack.push(id);
return build(modules[id]);
} finally {
delete inProgressModules[id];
requireStack.pop();
}
}
return modules[id].exports;
};
define = function (id, factory) {
if (modules[id]) {
throw "module " + id + " already defined";
}
modules[id] = {
id: id,
factory: factory
};
};
define.remove = function (id) {
delete modules[id];
};
define.moduleMap = modules;
})();
define("ov_gap", function(require, exports, module) {
var ovGap = {
callbackId: Math.floor(Math.random() * 2000000000),
callbacks: {},
commandQueue: [],
groupId: Math.floor(Math.random() * 300),
groups: {},
listeners: {},
invoke: function(cmd, params, onSuccess, onFail) {
if(!cmd) cmd = "defaultCommand";
if(!params) params = {};
this.callbackId ++;
this.callbacks[this.callbackId] = {
success: onSuccess,
fail: onFail
};
var rurl = "ovgap://" + cmd + "/" + JSON.stringify(params) + "/" + this.callbackId;
document.location = rurl;
},
dispatchCommand: function(cmd, params, onSuccess, onFail) {
if(!cmd) cmd = "defaultCommand";
if(!params) params = {};
this.callbackId ++;
this.callbacks[this.callbackId] = {
success: onSuccess,
fail: onFail
};
var command = cmd + "/" + JSON.stringify(params) + "/" + this.callbackId;
this.commandQueue.push(command);
},
fetchNativeCommands: function() {
var json = JSON.stringify(this.commandQueue);
this.commandQueue = [];
return json;
},
activate: function() {
document.location = "ovgap://ready";
},
// return group ID
createGroup: function() {
this.groupId ++;
this.groups[this.groupId] = [];
return this.groupId;
},
dispatchCommandInGroup: function(cmd, params, onSuccess, onFail, groupId) {
if (!this.groups[groupId]) return false;
if(!cmd) cmd = "defaultCommand";
if(!params) params = {};
this.callbackId ++;
this.callbacks[this.callbackId] = {
success: onSuccess,
fail: onFail
};
var command = cmd + "/" + JSON.stringify(params) + "/" + this.callbackId;
this.groups[groupId].push(command);
return true;
},
activateGroup: function(groupId) {
if (!this.groups[groupId]) return false;
document.location = "ovgap://group/" + groupId;
},
fetchNativeGroupCommands: function(groupId) {
if (!this.groups[groupId]) return [];
var json = JSON.stringify(this.groups[groupId]);
this.groups[groupId] = [];
return json;
},
callbackSuccess: function(callbackId, params) {
try {
ovGap.callbackFromNative(callbackId, params, true);
} catch (e) {
console.log("Error in error callback: " + callbackId + " = " + e);
}
},
callbackError: function(callbackId, params) {
try {
ovGap.callbackFromNative(callbackId, params, false);
} catch (e) {
console.log("Error in error callback: " + callbackId + " = " + e);
}
},
callbackFromNative: function(callbackId, params, isSuccess) {
var callback = this.callbacks[callbackId];
if (callback) {
if (isSuccess) {
callback.success && callback.success(callbackId, params);
} else {
callback.fail && callback.fail(callbackId, params);
}
delete ovGap.callbacks[callbackId];
};
},
addGapListener: function(listenId, onSuccess, onFail) {
if (!listenId || !onSuccess || !onFail) return;
this.listeners[listenId] = {
success : onSuccess,
fail : onFail
};
},
removeListener: function(listenId) {
if (!this.listeners[listenId]) return;
this.listeners[listenId] = null;
},
triggerListenerSuccess: function(listenId, params) {
if (!this.listeners[listenId]) return;
var listener = this.listeners[listenId];
listener.success && listener.success(listenId, params);
},
triggerListenerFail: function(listenId, params) {
if (!this.listeners[listenId]) return;
var listener = this.listeners[listenId];
listener.fail && listener.fail(listenId, params);
}
};
module.exports = ovGap;
});
window.ov_gap = require("ov_gap");
}) ();
给按钮添加一个点击事件，回调如下：
function onButtonClick() {
// 下面是我需要处理的事，处理完之后
alert('这里我是要处理一些事的，如果有需要的话。');
// 这里是回调我们前端与后端商量好的方法
// activityList是oc中的方法
window.ov_gap.invoke("activityList", null, success, fail);
}
这样就从JS回调到了iOS端的OC方法，然后处理我们想做的事。
可是这两个库都需要添加这些东西，做HTML5的人可不愿意，因为这样的话，对于IOS的处理是一种，对于安卓和WP呢？又得写一份吗？
于是我又去寻找别的库，有一个叫apache cordova的库，是支持ios,android,wp的，可是太大了，又是英文的，安装也很困难，学习成本太高，于是看了看就放弃了，这么大的库，给我们带来的可不一定是好处多于动坏处啊。
JavaScriptCore
转了一圈又回到了原生的，有一个库叫JavaScriptCore，这个是IOS7以后才开放的API，这可以极大的简化了我们的需求，非常的简单，
我们只需要注入一个方法，就可以在JS中调用此方法来跟原生的OC交互。
首先得加入库
#import <JavaScriptCore/JavaScriptCore.h>
JSContext这个可是关键。
// webView对象
@property (nonatomic, strong, readonly) UIWebView *webView;
@property (nonatomic, strong, readonly) JSContext *jsContext;
下面是在webview加载完成后， 关联JS与OC:
- (void)webViewDidFinishLoad:(UIWebView *)webView {
[_activityView stopAnimating];
[self dismiss];
if (_jsContext == nil) {
// 1.
_jsContext = [webView valueForKeyPath:@"documentView.webView.mainFrame.javaScriptContext"];
// 2. 关联打印异常
_jsContext.exceptionHandler = ^(JSContext *context, JSValue *exceptionValue) {
context.exception = exceptionValue;
DDLogVerbose(@"异常信息：%@", exceptionValue);
};
_jsContext[@"activityList"] = ^(NSDictionary *param) {
DDLogVerbose(@"%@", param);
};
// Mozilla/5.0 (iPhone; CPU iPhone OS 10_10 like Mac OS X) AppleWebKit/600.1.4 (KHTML, like Gecko) Mobile/12B411
id userAgent = [webView stringByEvaluatingJavaScriptFromString:@"navigator.userAgent"];
DDLogVerbose(@"%@", userAgent);
}
}
上面
activityList是商定好的方法名称，在JS中写法：
<input type="button" value="测试log" οnclick="activityList({'tytyty':'hehe'})" />
在点击的时候，直接回调是可以的。
写DEMO的过程中，由于 后台并没有提供好HTML5页面的交互来测试，需要自己写，这里是使用apache服务器，在本地创建一个HTML5页面，自己写一些JS来测试的，如果大家不知道怎么写JS，其实是很简单的，上w3cschool看一看，就明白了。
参考：http://blog.csdn.net/woaifen3344/article/details/42742893
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