Invoke method in objective c code from HTML code using UIWebView
Question
I have .html file in my iOS app. HTML file has few div blocks with onClick methods. When I tap on these blocks I invoke some javascript code in web view, but I need also know about these events in my source code.
For example when I tap on web element and onClick is called I need to invoke some method in the code eg - (void)didTouchedWebElementWithId
Can I do this stuff. Thanks.
1 answers
solution1
48 ACCPTED 2013-03-21 07:19:54
To call method of Objective-C in JS:
the below url helps in doing that
How to invoke Objective C method from Javascript and send back data to Javascript in iOS?
There is no way of executing, we make workaround by a navigation to other page and during the navigation, a webview delegate will watch for prefix of the navigation and execute the method we specified.
sample.html
<html>
<head>
<script type='text/javascript'>
function getText()
{
return document.getElementById('txtinput').value;
}
function locationChange()
{
window.location = 'ios:webToNativeCall';
}
</script>
</head>
<body style='overflow-x:hidden;overflow-y:hidden;'>
<h2 style = "font-size:16px;" align='center'>Hi Welcome to Webpage</h2>
<br/>
<p align='center' style = "font-size:12px;">Please Click the button after entering the text</p>
<br/>
<center>
<input type='text' style='width:90px;height:30px;' id='txtinput'/>
</center>
<br/>
<center>
<input type='button' style='width:90px;height:30px;' onclick='locationChange()' value='click me'>
</center>
</body>
</html>
Objective-C code
when you click button in html page the below delegate will fired and navigation cancelled because we return NO and respective method is called
- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType
{
if ([[[request URL] absoluteString] hasPrefix:@"ios:"]) {
// Call the given selector
[self performSelector:@selector(webToNativeCall)];
// Cancel the location change
return NO;
}
return YES;
}
- (void)webToNativeCall
{
NSString *returnvalue = [self.webviewForHtml stringByEvaluatingJavaScriptFromString:@"getText()"];
self.valueFromBrowser.text = [NSString stringWithFormat:@"From browser : %@", returnvalue ];
}
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