Question

I have created a Tab Bar Application, removed the default FirstView and SecondView and added the following two ViewControllers:

1. JustAnotherView (which is simply a UIViewController with a UIView inside)
2. MyListOfItems (which is a UIViewController with a TableView inside)

I have a 3rd ViewController called ListOfItemsDetailViewController with a UIView inside that is supposed to be called when the user touches one of the TableView cells.

The application compiles without issue. I can touch both Tab Bar buttons and the correct View appear.

PROBLEM:
When I click a TableView cell, the code to switch to the Detail View is executed (without crashing or error), but the View is NEVER shown.

Here is a screenshot of the application and the debugger with an NSLog that shows it made it past the pushViewController without crashing:

http://clip2net.com/clip/m52549/thumb640/1281588813-9c0ba-161kb.jpg

Here is the code.

MyListOfItemsViewController.h

#import <UIKit/UIKit.h>
#import <Foundation/Foundation.h>
#import "ListOfItemsDetailViewController.h";

@interface MyListOfItemsViewController : UIViewController {
    ListOfItemsDetailViewController *listOfItemsDetailViewController;
}

@property (nonatomic, retain) ListOfItemsDetailViewController *listOfItemsDetailViewController;


@end

Here is the MyListOfItemsViewController.m file:

#import "MyListOfItemsViewController.h"
@implementation MyListOfItemsViewController
@synthesize listOfItemsDetailViewController;

#pragma mark -
#pragma mark View lifecycle

- (void)viewDidLoad {
    [super viewDidLoad];

    // Uncomment the following line to display an Edit button in the navigation bar for this view controller.
    // self.navigationItem.rightBarButtonItem = self.editButtonItem;
    self.title = @"My List Of Items";
    NSLog(@"My List Of Items Did Load");
}

#pragma mark -
#pragma mark Table view data source
// Customize the number of sections in the table view.
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
    return 1;
}
// Customize the number of rows in the table view.
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {

    return 5;
}


// Customize the appearance of table view cells.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {

    static NSString *CellIdentifier = @"Cell";
    NSString *cellMessage;

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if (cell == nil) {
        cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
    }

    cellMessage = [NSString stringWithFormat:@"indexPath: %d",indexPath.row];       
    cell.textLabel.text = cellMessage;
    return cell;
}

#pragma mark -
#pragma mark Table view delegate

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {

    ListOfItemsDetailViewController *vcListOfItemsDetail = [[ListOfItemsDetailViewController alloc] 
                                    initWithNibName:@"ListOfItemsDetail" bundle:[NSBundle mainBundle]];
    self.listOfItemsDetailViewController = vcListOfItemsDetail;
    [vcListOfItemsDetail release];
    [self.navigationController pushViewController:self.listOfItemsDetailViewController animated:YES];

    NSLog(@"Did Execute didSelectRowAtIndexPath WITHOUT Crashing or Error.");

}

#pragma mark -
#pragma mark Memory management

- (void)didReceiveMemoryWarning {
    // Releases the view if it doesn't have a superview.
    [super didReceiveMemoryWarning];

    // Relinquish ownership any cached data, images, etc that aren't in use.
}

- (void)viewDidUnload {
    // Relinquish ownership of anything that can be recreated in viewDidLoad or on demand.
    // For example: self.myOutlet = nil;
    NSLog(@"My List Of Items View Did Unload");
}


- (void)dealloc {
    [super dealloc];
}



@end

Please help. It will be very much appreciated!!!

I have been driving myself crazy trying to get basic navigation down in the iOS platform.

Also, pardon the layperson question, I know that most of you already understand how to do this.

Thanks in advance.
Jaosn

Answer 1

In tableView:didSelectRowAtIndexPath: you are referencing a navigationController by self.navigationController, that likely doesn’t exist. You have to use a UINavigationController as one view controller in you tabView and the rootViewController of that navigationController should be MyListOfItemsViewController.

Please note that you need a UINavigationController for your detail view to push on and self.navigationController is only a way to retrieve one, that has been created and inserted into the hierarchy before.