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目前在网上看到很多介绍IOS里面WebView和JavaScript交互的文章。如果你想用网页去写一个app,那么我推荐 你去用PhoneGap (它是一个用基于HTML,CSS和JavaScript的,创建移动跨平台移动应用程序的快速开发平台)。如果你网页只是你app的一部分那么还是要去了解一下它们之间交互的原理。
目前github上已经有相对成熟的开源项目,例如 WebViewJavascriptBridge ,你可以直接利用现成的框架快速实现js交互。介绍bridge的文章挺多,这里分析一个介绍的比较全面的博客:My_Lord 。有兴趣的同学可以去转转~
现在,我来为大家分析一下其中的原理。其实很简单,在IOS中,WebView和JavaScript直接的调用就是一个实例方法、一个回调代理:
首先来看WebView调用js的方法:
//调用特定的js方法
[_myWebView stringByEvaluatingJavaScriptFromString:@'myFunction('Hello,js!');'];
其中myFunction()为你的html页面里边早已写好的js函数。至于穿不穿参数,看你的选择。
接下来是js调用WebView的方法,原理就是利用WebView的代理方法:
- (BOOL)<span id='8_nwp' style='list-style: none; width: auto; height: auto; float: none;'><a target=_blank id='8_nwl' href='http://cpro.baidu.com/cpro/ui/uijs.php?rs=1&u=http%3A%2F%2Fwww%2E350351%2Ecom%2Fbianchengyuyan%2FObjective%5Fc%2F318278%2Ehtml&p=baidu&c=news&n=10&t=tpclicked3_hc&q=83045059_cpr&k=web&k0=web&k1=%BF%AA%D4%B4&k2=javascript&k3=%BF%AA%B7%A2%C6%BD%CC%A8&k4=%B4%FA%C0%ED&k5=app&sid=c1d1272fce2e94d1&ch=0&tu=u1807396&jk=f961445607926bba&cf=29&fv=15&stid=9&urlid=0&luki=2&seller_id=1&di=128' target='_blank' mpid='8' style='list-style: none; padding: 0px 10px; margin: 0px; color: rgb(0, 182, 137); text-decoration: none;'><span style='list-style: none; color: rgb(0, 0, 255); width: auto; height: auto;'>web</span></a></span>View:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType
{
}
这个代理将会在js调用document.location的时候相应。接下来我们要定义好它们之间的暗号。
function sendCommand(cmd,param){
var url='testapp:' cmd ':' param;
document.location = url;
}
我们定义以testapp:开头的url为我们的暗号。接下来是在代理里边识别该暗号:
#pragma <span id='4_nwp' style='list-style: none; width: auto; height: auto; float: none;'><a target=_blank id='4_nwl' href='http://cpro.baidu.com/cpro/ui/uijs.php?rs=1&u=http%3A%2F%2Fwww%2E350351%2Ecom%2Fbianchengyuyan%2FObjective%5Fc%2F318278%2Ehtml&p=baidu&c=news&n=10&t=tpclicked3_hc&q=83045059_cpr&k=mark&k0=mark&k1=ios&k2=web&k3=%BF%AA%D4%B4&k4=javascript&k5=%BF%AA%B7%A2%C6%BD%CC%A8&sid=c1d1272fce2e94d1&ch=0&tu=u1807396&jk=f961445607926bba&cf=29&fv=15&stid=9&urlid=0&luki=10&seller_id=1&di=128' target='_blank' mpid='4' style='list-style: none; padding: 0px 10px; margin: 0px; color: rgb(0, 182, 137); text-decoration: none;'><span style='list-style: none; color: rgb(0, 0, 255); width: auto; height: auto;'>mark</span></a></span> - UIWebViewDelegate
- (BOOL)<span id='5_nwp' style='list-style: none; width: auto; height: auto; float: none;'><a target=_blank id='5_nwl' href='http://cpro.baidu.com/cpro/ui/uijs.php?rs=1&u=http%3A%2F%2Fwww%2E350351%2Ecom%2Fbianchengyuyan%2FObjective%5Fc%2F318278%2Ehtml&p=baidu&c=news&n=10&t=tpclicked3_hc&q=83045059_cpr&k=web&k0=web&k1=%BF%AA%D4%B4&k2=javascript&k3=%BF%AA%B7%A2%C6%BD%CC%A8&k4=%B4%FA%C0%ED&k5=app&sid=c1d1272fce2e94d1&ch=0&tu=u1807396&jk=f961445607926bba&cf=29&fv=15&stid=9&urlid=0&luki=2&seller_id=1&di=128' target='_blank' mpid='5' style='list-style: none; padding: 0px 10px; margin: 0px; color: rgb(0, 182, 137); text-decoration: none;'><span style='list-style: none; color: rgb(0, 0, 255); width: auto; height: auto;'>web</span></a></span>View:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType
{
static int count = 1;
NSString *requestString = [[request.URL absoluteString]stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding];;
NSArray *components = [requestString componentsSeparatedByString:@':'];
if ([components count] > 1 && [(NSString *)[components objectAtIndex:0] isEqualToString:@'test<span id='6_nwp' style='list-style: none; width: auto; height: auto; float: none;'><a target=_blank id='6_nwl' href='http://cpro.baidu.com/cpro/ui/uijs.php?rs=1&u=http%3A%2F%2Fwww%2E350351%2Ecom%2Fbianchengyuyan%2FObjective%5Fc%2F318278%2Ehtml&p=baidu&c=news&n=10&t=tpclicked3_hc&q=83045059_cpr&k=app&k0=app&k1=%B2%A9%BF%CD&k2=%CD%A8%D0%C5&k3=mark&k4=ios&k5=web&sid=c1d1272fce2e94d1&ch=0&tu=u1807396&jk=f961445607926bba&cf=29&fv=15&stid=9&urlid=0&luki=7&seller_id=1&di=128' target='_blank' mpid='6' style='list-style: none; padding: 0px 10px; margin: 0px; color: rgb(0, 182, 137); text-decoration: none;'><span style='list-style: none; color: rgb(0, 0, 255); width: auto; height: auto;'>app</span></a></span>']) {
//解析约定的指令
if([(NSString *)[components objectAtIndex:1] isEqualToString:@'alert'])
{
UIAlertView *alert = [[UIAlertView alloc]
initWithTitle:[NSString stringWithFormat:@'消息%d',count ] message:[components objectAtIndex:2]
delegate:self cancelButtonTitle:nil
otherButtonTitles:@'OK', nil];
[alert show];
}
return NO;
}
return YES;
}
大功告成!是不是很简单~
只要我们定义好了传递的暗号,我们就可以让双方相互“通信”了!
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