Question

My first view displays an image and action indicator while web-servers and database function are run in that background. I want the application to go to my tab view when the functions have been completed. How do I do this?

Here is what the views look like.

What I have tried:

TabBarViewController *tab = [[TabBarViewController alloc]init];
[self presentViewController:tab animated:NO completion:nil];

and

[self performSegueWithIdentifier:@"first" sender:self];

Please can you help my to understand how to do this. I have spent many hours googling this problem and couldn’t work out how to do it.

Thanks

EDIT: Added Code

Answer 1

You can use GCD to make this happen.

For instance in your firstViewController where you trigger downloading you can do:

dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_LOW, 0), ^{
[model downloadData];
dispatch_sync(dispatch_get_main_queue(), ^{
[self performSegueWithIdentifier:@"YourSegueIdentifier" sender:self];
});
});

I assume your downloadData method is synchronous, if not you can use notifications in your model. Once data is retrieved you could postNamedNotification from NSNotificationCenter and in firstViewController you could register for notification and after receiving it you would call performSegueWithIdentifier