Question

I have searched a lot about this topic and I can’t get this code work. When I execute it, it only shows my test NSLog but the code to go from one view to another doesn’t do anything. Here you have the following code:

//FirstViewController.h

#import <UIKit/UIKit.h>
#import "StationDetailsViewController.h"


@interface FirstViewController : UIViewController{
  NSArray *ListaEstaciones;
  NSArray *ListaID;
}
@property (nonatomic, retain) NSArray *ListaEstaciones;
@property (nonatomic, retain) NSArray *ListaID;
@end

//FirstViewController.m

#import "FirstViewController.h"
#import "StationDetailsViewController.h"
@implementation FirstViewController
@synthesize ListaEstaciones;
@synthesize ListaID;

//...

- (void)tableView: (UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath{
NSLog(@"Pushing...");
StationDetailsViewController *controller = [[StationDetailsViewController alloc] initWithNibName:@"StationDetailsViewController" bundle:nil];
[[self navigationController] pushViewController:controller animated:YES];
[controller release], controller = nil; 
}

@end

I have tried lots of tutorials and my book but I don’t know what is wrong. Thanks a lot, guys.

EDIT: Reading your answers I found that the error is on AppDelegate.m where rootViewController is defined.

//AppDelegate.m

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    // Override point for customization after application launch.
    UIViewController *viewController1 = [[FirstViewController alloc] initWithNibName:@"FirstViewController" bundle:nil];
    UIViewController *viewController2 = [[SecondViewController alloc] initWithNibName:@"SecondViewController" bundle:nil];
    UIViewController *viewController3 = [[ThirdViewController alloc] initWithNibName:@"ThirdViewController" bundle:nil];
    self.tabBarController = [[UITabBarController alloc] init];
    self.tabBarController.viewControllers = [NSArray arrayWithObjects:viewController1, viewController2, viewController3, nil];
    self.window.rootViewController = self.tabBarController;
    [self.window makeKeyAndVisible];

    return YES;
}

I don’t know what to edit here to make this:
[[self navigationController] pushViewController:controller animated:YES];
work properly.

Answer 1

i think the problem is in [self navigationController] .. put a break point on this line of code and probaly you will find its value = nil cuz of that you are not having your detail controller .. you could solve this like that UINavigationController *nav = [[UINavigationController alloc] initWithRootViewController:yourMainViewControllerInstance];

This The appDelegate Code :

self.window = [[[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]] autorelease];
// Override point for customization after application launch.
UIViewController *firstViewController = [[[FirstViewController alloc] initWithNibName:@"FBConFirstViewController" bundle:nil] autorelease];
UIViewController *secondViewController = [[[SecondViewController alloc] initWithNibName:@"FBConSecondViewController" bundle:nil] autorelease];
self.tabBarController = [[[UITabBarController alloc] init] autorelease];
 UINavigationController *nav = [[[UINavigationController alloc] initWithRootViewController:firstViewController]autorelease];
self.tabBarController.viewControllers = [NSArray arrayWithObjects:nav, secondViewController, nil];
self.window.rootViewController = self.tabBarController;
[self.window makeKeyAndVisible];