[掌眼]UIWebView 显示正在加载网页

- (void)webViewDidStartLoad:(UIWebView *)webView   
{  
    [UIApplication sharedApplication].networkActivityIndicatorVisible = YES;   
}   
- (void)webViewDidFinishLoad:(UIWebView *)webView   
{  
    [UIApplication sharedApplication].networkActivityIndicatorVisible = NO;   
}   
- (void)webView:(UIWebView *)webView didFailLoadWithError:(NSError *)error   
{
    [UIApplication sharedApplication].networkActivityIndicatorVisible = NO;  
}