UIViewController to know if it got pushed or popped? - objective-c

Question

I have a main UITableView, when cell is pressed it goes to another UITableView and when a cell is pressed there it goes to a DetailView of that cell.
I want the middle UITableView to behave differently depending on if the detailView got popped or the UITableView itself got pushed. If the view got pushed on from the main table I want to scroll to the top, if it is shown after a DetailView got popped I want it to stay at the same position.
Any suggestions?

Answer 1

you could call a scrollToTop method on the DetailViewController after you have pushed it to the navigationController.
Something like that:
if (!detailViewController) {
detailViewController = [[DetailViewController alloc] initWithNibName:nil bundle:nil];
}
[self.navigationController pushViewController:detailViewController animated:YES];
[detailViewController scrollToTop];
// or use the tableView directly:
// [detailViewController.tableView scrollToRowAtIndexPath:[NSIndexPath indexPathForRow:0 inSection:0] atScrollPosition:UITableViewScrollPositionTop animated:YES];

Answer 2

In your Middle View Controller, examine which view is next-to-display directly from the UINavigationController stack:
- (void)viewWillDisappear:(BOOL)animated
{
if ([self.navigationController.topViewController isEqual:(UITableViewController *)tvcDetailView]) {
// Detail view has been pushed onto the UINavigationController stack
}
else {
// Middle view has been popped from the UINavigationController stack
}
}

Answer 3

Create a BOOL #property on your middle UIViewController property called wasPushed or something similar, and when you initialise it from UIViewController 1, set the property on the new instance, push it onto the nav stack and you can then use your property in your middle view controller's loadView, viewDidLoad, viewWill/DidAppear methods.
As soon as you've used it, set it back to FALSE or NO (or whatever) and when you end up coming back to it due to popping off your 3rd view controller you'll have it as FALSE/NO in your loadView, viewDidLoad etc.. methods.