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iphoneiosobjective-cipadmathjax

UIWebView's content height returns wrong value while using mathjax

I am using mathjax for displaying the mathematical expressions on UIWebView. So i want to change the UIWebView height dynamically. For that , i have used 

CGFloat newHeight = [[self.questionWebView stringByEvaluatingJavaScriptFromString:@"document.documentElement.scrollHeight;"] floatValue];

in webViewDidFinishLoad: delegate method.

Here my problem is if i am using normal expression the UIWebView height returns correct value as like in the following image,

enter image description here

if i enter the expression which contains /,(,) it will give the wrong height as like in the following image

enter image description here

 NSString *html = [NSString stringWithFormat:@"<html><head><title>Untitled</title><meta http-equiv=\"Content-Type\" content=\"text/html; charset=UTF-8\" /><meta http-equiv=\"X-UA-Compatible\" content=\"IE=edge\" /><script type=\"text/x-mathjax-config\">MathJax.Hub.Config({extensions: [\"tex2jax.js\"],jax: [\"input/TeX\",\"output/HTML-CSS\"],tex2jax: {inlineMath: [[\"$\",\"$\"],[\"\\(\",\"\\)\"]]}});</script><script type=\"text/javascript\" src=\"../MathJax.js?config=AM_HTMLorMML-full\"></script></head><style>.Question {font-family:'Times New Roman',arial;font-weight:normal;font-size:12px;color:#323232;}</style><body><table cellpadding=\"0\" cellspacing=\"0\" border=\"0\" class=\"Question\" align=\"left\" width=\"260\" height=\"40\"><tr><td> `x + 3 = 2` </td></tr></div></body></html>"];

[self writeStringToFile:tempDir fileName:@"test1.html" pathName:filePath content:html];

NSURLRequest* req = [[NSURLRequest alloc] initWithURL:url];

[self.myWebView loadRequest:req];

In writeStringToFile: method,

-(void)writeStringToFile:(NSString *)dir fileName:(NSString *)strFileName pathName:(NSString *)strPath content:(NSString *)strContent{

    NSString *path = [dir stringByAppendingPathComponent:strFileName];
    NSString *foo0 = @"<html><head><meta name='viewport' content='initial-scale=1.0;maximum-scale=100.0;user-scalable=1'/>"
    "<script type='text/javascript' src='";
    NSString *foo1 = @"?config=AM_HTMLorMML-full'></script>"
    "</head>"
    "<body>";
    NSString *foo2 = @"</body></html>";
    NSString *fooFinal = [NSString stringWithFormat:@"%@%@%@%@%@",foo0,strPath,foo1,strContent,foo2];

    [fooFinal writeToFile:path atomically:YES encoding:NSUTF8StringEncoding error:nil];
}

How to get the exact height?

Thanks in advance!

Solution

  • Finally after a long research, i have found the solution with the help of @Davide Cervone answer and the sample https://github.com/dannywartnaby/KPWebViewInterceptor,

    Just added the objective-c method call in .html file

    <script type="text/x-mathjax-config">
  MathJax.Hub.Queue(function myFunction() {
                          objc_msgsend('myFunction');
                          });
</script>

    in.js file

    var KP_INTERCEPTOR_INVOCATION_COMMAND = "invoke"
var KP_INTERCEPTOR_SEPERATOR = ":"
function objc_msgsend() {
    var selector = arguments[0];
    var invocation = selector;

    if ( arguments.length > 1 ) {

        for( var i = 1; i < arguments.length; i++ ) {
            invocation = invocation + KP_INTERCEPTOR_SEPERATOR + arguments[i];
        }
    }

    window.location = KP_INTERCEPTOR_INVOCATION_COMMAND + KP_INTERCEPTOR_SEPERATOR + invocation;
}

    in webView Delegate

    - (BOOL)webView:(UIWebView *)source shouldStartLoadWithRequest:(NSURLRequest *)request  navigationType:(UIWebViewNavigationType)navigationType {

    if([[[request URL] absoluteString] hasPrefix:@"invoke"]) {
        [self myFunction];
        return NO;
    }
    return YES;
}