Cannot Dismiss Modal View Controller - iphone

Question

I'm having a problem getting my modal view controller to properly display and then dismiss. Basically I have a modally displayed login window and I want to dismiss it after all the data that I want to display is loaded from the database. if I call
[self dismissModalViewControllerAnimated:YES] from within the LoginViewController class it works perfectly fine but if I call
[[mainController modalViewController] dismissModalViewControllerAnimated:YES] from within my datamanager class after I have successfully imported the data nothing happens. Which is extremely confusing because [mainController modalViewController] points to the locationManager class.
Does anybody have any ideas as to why this isn't working? I'm programming for iOS 4 if that matters.
Thanks!

Answer 1

OK So I figured this out. Basically what was happening was that the [self dismissModalViewController] call was happening on another thread which for whatever reason means that the object did not properly process the dismiss message. I ended up using a notification and then called dismissModalView controller like so:
- (void)dismissSelf
{
[self dismissModalViewControllerAnimated:YES];
}
- (void)receiveDismissNotification:(NSNotification *) note
{
[self performSelectorOnMainThread:#selector(dismissSelf) withObject:nil waitUntilDone:NO];
}
which works

Answer 2

The proper way to dismiss a modal view controller is to call -dismissModalViewControllerAnimated: on the view controller that presented it. Thus it should be [_splitViewController dismissModalViewControllerAnimated:YES];.
From your comment, you need to call -dismissModalViewControllerAnimated: on the main thread, you can do this like so:
dispatch_async(dispatch_get_main_queue(), ^{
[_splitViewController dismissModalViewControllerAnimated:YES];
});

Answer 3

To close the Model View Controller use following code
[self dismissModalViewControllerAnimated:YES];
This code works with ios 5 also.
For presenting the model view controller
if (self.viewController!=nil)
{
//sanity check for view controller
[self.viewController SOMEVIEW animated:YES];
}