MBProgressHUD display messages one over the other - iphone

Question

In the viewDidload method, i am using MBProgressHUD to show an activity indicator until data is downloaded from the net, and thereafter to check if the application has enabled GPS. based on this i alert the user using MBProgressHUD.
My code;
ViewDidLoad
hudForDownloadData = [[MBProgressHUD alloc] initWithView:self.navigationController.view];
[self.navigationController.view hudForDownloadData ];
hudForDownloadData .delegate = self;
hudForDownloadData .labelText = #"Loading";
hudForDownloadData .detailsLabelText = #"updating data";
[hudForDownloadData showWhileExecuting:#selector(downloadDataFromWebService) onTarget:self withObject:nil animated:YES];
[self downloadDataFromWebService]; // This method is called, and then data is downloaded from the webservice, once the data is downloaded i will remove the `MBProgressHUD ` alert
Now i am checking if the application has enabled access to GPS, and alert the user if not.
hudForGPS = [[MBProgressHUD alloc] initWithView:self.navigationController.view];
[self.navigationController.view addSubview:HUD];
hudForGPS .delegate = self;
hudForGPS .labelText = #"Loading";
hudForGPS .detailsLabelText = #"updating data";
[hudForGPS showWhileExecuting:#selector(checkIfApplicationEnabledGPS)
onTarget:self withObject:nil animated:YES]; // This will only take a
maximum of 2-3 seconds. and i will remove it after that
The problem is that; when the internet/wifi is down, the hudForDownloadData will continuously animate (display uiactivityindicator). In the meantime hudForGPS will also execute. But it will display below hudForDownloadData . So the user will not be able to see it.
What i want to do is to execute the checkIfApplicationEnabledGPS first, and wait till its alert finishes (it will only take 2-3 seconds), and then load execute the downloadDataFromWebService where if the internet/wifi is not available it will display forever.
How can i do this programatically ?

Answer 1

Execute checkIfApplicationEnabledGPS first and when it is finished,you show an alert box,If you are using UiAlertView to show the alert then you can handle it's delegate:-
-(void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex
when the user presses ok button in UiAlert view you can override the above delegate with hudForDownloadData
In this way both the checkIfApplicationEnabledGPS and hudForDownloadData will be executed one after the other