Knowing when AJAX has loaded in UIWebView

问题:

I have a UIWebView and one page has an AJAX component whose content changes when the user clicks a button. How can I know when the content has loaded inside the UIWebView?

回答1:

You'll need to do two things:

1. In your JavaScript code, have the XMLHTTPRequest signal that the AJAX request is complete with a custom URL:

   var req = new XMLHttpRequest();  
   req.open('GET', 'http://www.mozilla.org/', true);  
   req.onreadystatechange = function (aEvt) {  
     if (req.readyState == 4) {  
        if(req.status == 200) { 
          window.location = "myspecialurl:foo"
        }
     }  
   };  
   

2. In your native code, you'll need to implement a UIWebView delegate that listens for this custom URL:

   - (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType 
   {
     if([[[request URL] absoluteString] isEqualToString:@"myspecialurl:foo"]) {
        // Your code for when the AJAX request completes.
        return NO;
     }
     return YES;
   }
   

No assurances this code parses/compiles but should give you the idea how to do it.