Reused UIWebView showing previous loaded content for a brief second on iPhone

Question

In one of my apps I reuse a webview. Each time the user enters a certain view on reload cached data to the webview using the method :-

- (void)loadData:(NSData *)data MIMEType:(NSString *)MIMEType textEncodingName:(NSString *)encodingName baseURL:(NSURL *)baseURL

and I wait for the callback call

- (void) webViewDidFinishLoad:(UIWebView *)webView.

In the mean time I hide the webview and show a 'loading' label. Only when I receive webViewDidFinishLoad do I show the webview.

Many times what happens I see the previous data that was loaded to the webview for a brief second before the new data I loaded kicks in.

I already added a delay of 0.2 seconds before showing the webview but it didn't help.

Instead of solving this by adding more time to the delay does anyone know how to solve this issue or maybe clear old data from a webview without release and allocating it every time?

Answer 1

Thanks malaki1974, in my case I wasn't using a modal view. When I sat with an Apple engineer on WWDC 2010 and asked him this question his answer was simply: "Don't reuse UIWebViews, that's not how they were ment to be used." Since then I make sure to calls this set of lines before allocating a new UIWebView

[self.myWebView removeFromSuperview];
self.myWebView.delegate = nil;
[self.myWebView stopLoading];
[self.myWebView release];

That solved the issue.

Answer 2

Clear the contents of the webview before you try to load new content

[self loadRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:@"about:blank"]]];