使用UIWebViewDelegate协议方法webViewDidFinishLoad和webView的isLoading属性

 - (void)webViewDidFinishLoad:(UIWebView *)webView
 {
    //Check here if still webview is loding the content
    if (webView.isLoading)
       return;

    //after code when webview finishes
    NSLog(@"Webview loding finished");
 }