Initialize Self.NaviationController

Question

I have a tab-based application. In SecondViewController, there is a UITableView with several cells. When you swipe on a cell, you are sent to another view controller, speciesController. The below code works to send the app to another view, and it does set up a navigation bar, but there is no back button.

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
    SpeciesViewController* speciesController = [[SpeciesViewController alloc]initWithNibName:@"SpeciesViewController" bundle:nil];


    Species *theSpecies = [fetchedResultsController objectAtIndexPath:indexPath];
    speciesController.theSpecies = theSpecies;

    switch (sortBySegmentedControl.selectedSegmentIndex) {
        case kSortByCommonNameFirst:
            speciesController.title = [theSpecies commonNameFirstLast];
            break;
        case kSortByCommonNameLast:
            speciesController.title = [theSpecies commonNameLastFirst];
            break;
        case kSortByScientificName:
            speciesController.title = [[NSString alloc] initWithFormat:@"%@%@",
                                       [theSpecies.scientificName substringToIndex:1],
                                       [[theSpecies.scientificName substringFromIndex:1] lowercaseString]];
            break;
        default:
            break;
    }

    speciesController.hidesBottomBarWhenPushed = YES;
    //self.navigationItem.backBarButtonItem = [[UIBarButtonItem alloc] initWithTitle:@"Back" style:UIBarButtonItemStylePlain target:nil action:nil];

    //// Store current index path for viewDidAppear animation. ////
    self->currentSelectedIndexPath = indexPath;
    UINavigationController *navBar=[[UINavigationController alloc]initWithRootViewController:speciesController];
    navBar.navigationItem.backBarButtonItem = [[UIBarButtonItem alloc] initWithTitle:@"Back" style:UIBarButtonItemStylePlain target:nil action:nil];
    [self presentViewController:navBar animated:YES completion:nil];

}

I realize that to have a backbutton, you need to push the current view onto the navigation controller stack. However, changing

navBar.navigationItem.backBarButtonItem = [[UIBarButtonItem alloc] initWithTitle:@"Back" style:UIBarButtonItemStylePlain target:nil action:nil];
[self presentViewController:navBar animated:YES completion:nil];

to

self.navigationItem.backBarButtonItem = [[UIBarButtonItem alloc] initWithTitle:@"Back" style:UIBarButtonItemStylePlain target:nil action:nil];
[self.navigationController pushViewController:navBar animated:NO];

Doesn't work. In fact, the app fails to change to a different view, and I believe this is because there is no self.navigationController

I tried to add/initialize one with this line:

UINavigationController *navigationController=[[UINavigationController alloc]initWithRootViewController:self];

but that caused the application to crash.

I appreciate any information about adding a navigation controller to an app (in storyboard or programatically). I'm afraid most of the examples I saw were outdated, from 2011 or so with methods like self.window addSubview...

Thank you!

Answer 1

Instead of having SecondViewController as a Tab Item, set that Tab Item to a Navigation Controller with SecondViewController as its Root VC.

Then, on didSelectRowAtIndexPath, all you have to do is:

[self.navigationController pushViewController: speciesController animated:YES];

The "back button" will automatically be there.