Show AlertView when tapping tab in TabBar - ios

Question

What I need
I'd like to show an UIAlertView "Loading..." when I tap on a tab in my tabBar.
Reason why I want to do that
This is because that particular tab contains a UIWebView and is very slow, so when I tap on that tab it seems like my app is doing absolutely nothing for a few seconds. It is very ugly, so I'd like to show something to make the user know that the app is actually working.
Questions
In which position do I have to put it? If I write it in the ViewDidLoad, the AlertView is shown after those orrible few seconds. Is AlertView the best choice?
Thank you all.

Answer 1

add MBProgressHUD to your UIWebView viewDidLoad method
- (void)viewDidLoad {
[super viewDidLoad];
self.webView.delegate = self;
MBProgressHUD *hud = [MBProgressHUD showHUDAddedTo:self.view animated:YES];
hud.labelText = #"Loading...";
}
- (void)webViewDidFinishLoad:(UIWebView *)webView {
[hud hide:YES];
}

Answer 2

UIAlerView is not a good idea.
//Delegate method of UIWebView
- (void)webViewDidStartLoad:(UIWebView *)webView
{
if(![[UIApplication sharedApplication] isNetworkActivityIndicatorVisible])
{
[[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:YES];
}
}
//Delegate method of UIWebView
- (void)webViewDidFinishLoad:(UIWebView *)webView_
{
if([[UIApplication sharedApplication] isNetworkActivityIndicatorVisible])
{
[[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:NO];
}
}

Answer 3

Set your tabBar as a delegate on viewDidLoad
- (void)viewDidLoad
{
[super viewDidLoad];
//Setting tabBarController as a delegate
self.tabBarController.delegate = self;
}
On your interface at .h method add delegate <UITabBarControllerDelegate>
Implement this function and add your loading view, for each time that you press tabBar. The method below gets executed always when the user taps an item on tabbar.
- (void)tabBarController:(UITabBarController *)tabBarController didSelectViewController:(UIViewController *)viewController
{
//Show loading form here
[MBProgressHUD showHUDAddedTo:self.view animated:YES];
dispatch_async(dispatch_get_global_queue( DISPATCH_QUEUE_PRIORITY_LOW, 0), ^{
// Do something...
dispatch_async(dispatch_get_main_queue(), ^{
[MBProgressHUD hideHUDForView:self.view animated:YES];
});
});
}
P.S You need to add this method and set to delegate to every viewController which you need to show the alert view (Loading View)
For a loading view you can also load use MBProgressHUD as KingBabar pointed out. It has great features.