因为项目需要做一个活动,而这个活动的信息是源于HTML5写的,而这个操作网页的过程上,
是需要到与原生APP这边交互的,因为这就增加了一个需求,那就是与JS交互。
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。
花了两天的时间,反反复复地研究了WebviewJavaScriptBridge和OVGap这两个库,也在网上搜索了很多的
相关博客看,可是都没有满足我的需求。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 + ':' + 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。
将下来是使用OVGap这个库。
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:
[javascript] view plain copy print?在CODE上查看代码片派生到我的代码片
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。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[javascript] view plain copy print?在CODE上查看代码片派生到我的代码片#importJSContext这个可是关键。
[objc] view plain copy print?在CODE上查看代码片派生到我的代码片
// 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:[javascript] view plain copy print?在CODE上查看代码片派生到我的代码片在点击的时候,直接回调是可以的。那么经过这两天的摸索,学习到了很多的知识。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,我这里是使用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,so easy!!!!之所以要写下这篇文章,是因为我发现在网上搜索出来的文章中,都是相互复制的,看来看去都是一样的东西而且还都是OC调JS的代码,实在是不快。写下的点滴,希望对大家有用。另外,也许我上面所讲的一些关于OVGap和WebviewJavaScriptBridge的知识是有不正确的地方,还请指出来,你们的反馈,会是对我最大的帮助,谢谢!