Pushing UIViewController onto a UINavigationController

Question

The other day I asked about using a UINavigationController as a child of a UIViewController. I got that working via the answer. Now what I'm trying to do is push a controller onto the nav stack. When a table cell is touched, I do the following:

- (void) showSetup {
    NSLog(@"Showing Setup");
    SetupViewController *controller = [[SetupViewController alloc]initWithNibName:@"SetupViewController" bundle:nil];
    self.setupViewController = controller;
    self.setupViewController.title = @"Setup";
    [self.navigationController pushViewController:self.setupViewController animated:YES];
    [controller release];
}

I can see the log statement in my console, but the view never changes. Am I missing something?

Is there a reason why you have a setupViewController property? — Larry Hipp
@hipplar - that's not the problem. I have no good reason for it other than examples I used from books do it this way. However, I changed it and I still get the same results. — Gregg
Have you checked that controller is non-nil? If it is nil, then check your SetupViewController -initWithNibName: and make sure that it is returning properly. — westsider

jstevenco jstevenco · Accepted Answer · 2011-01-03T23:19:32

Hmmm, well it's a bit tricky without knowing the details of your implementation -- I assumed that you implemented your navigation controller as in the linked article. Also although you give no details it sounds like you've added a table view controller somewhere along the line, so I made the UIViewController conform to the UITableView protocols to handle everything in one place:

@interface SOViewController : UIViewController<UITableViewDelegate,UITableViewDataSource > {

  UINavigationController* navController;
}

- (IBAction) pushMe:(id)sender;
@end

I dropped a button on the SOViewController's view in IB and wired the pushMe: action to it. I also created another UIViewController-based class called JunkController and dropped a "Junk" label on it's view in IB -- that's all I did in IB. In the SOViewController's viewDidLoad:

navController = [[[UINavigationController alloc] init] retain];
navController.navigationBar.barStyle = UIBarStyleBlackOpaque;
navController.toolbarHidden = YES;

UITableViewController* tvController = [[UITableViewController alloc] init];
UITableView* tv = [[UITableView alloc] init];
tvController.tableView = tv;
tv.delegate = self;
tv.dataSource = self;
[navController setViewControllers:[NSArray arrayWithObject:tvController]];

In the pushMe: action implementation:

[self presentModalViewController:navController animated:YES];

Implemented the tableView delegate and datasource methods; for selection:

- (void) tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath  { 
    NSLog(@"row selected");
    JunkController* junk = [[JunkController alloc] initWithNibName:@"junkcontroller" bundle:nil];
    [navController pushViewController:junk animated:YES];
    [junk release];
}

This should yield an app that surfaces a screen with a "Push me" button. When that button is pressed you should get an animated modal navigation-based table view -- mine had one row in it that contained a label "select me". Touching this row should animate the junk controller into view.

Pushing UIViewController onto a UINavigationController

2 Answers