Unable to navigate to next page iPhone

Question

I am new to iPhone developer,

I have 4 page in my Application, my Application is viewBasedApplication.

I made my 1st page(LicAppViewController) as RootViewController, here is my code.

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    self.window = [[[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]] autorelease]; 
    self.viewController = [[[LicAppViewController alloc] initWithNibName:@"LicAppViewController" bundle:nil] autorelease]; 

    UINavigationController *navigationController=[[UINavigationController alloc] initWithRootViewController:self.viewController];
    [self.window addSubview:navigationController.view];
    [self.window makeKeyAndVisible];
    return YES; 
}

on button click i am navigation to 2nd page(PlanPage)

-(void)btnClicked{

    PlanPage *viewController = [[PlanPage alloc]initWithNibName:@"PlanPage" bundle:nil];
    [UIView beginAnimations:@"Flip" context:nil]; 
    [UIView setAnimationDuration:0.7]; 
    [UIView setAnimationCurve:UIViewAnimationOptionCurveEaseInOut]; 
    [UIView setAnimationTransition:UIViewAnimationTransitionFlipFromLeft forView:self.navigationController.view cache:NO]; 
    [self.navigationController pushViewController:viewController animated:YES];
    [UIView commitAnimations];
    [viewController release];

}

till now it is working fine, but when i select a row in 2nd page it crashes my application, i want to navigate to 3rd page(DetailPlanPage), here is my code

    DetailPlanPage *nextController = [[DetailPlanPage alloc] initWithNibName:@"DetailPlanPage" bundle:nil];
    [self.navigationController presentModalViewController:nextController animated:TRUE];

but when i write, this line:

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

instead of:

       [self.navigationController presentModalViewController:nextController animated:TRUE];

it's working fine. (I am not sure but crash of my application may be because of viewBased Application)

Thanks In Advance !

Answer 1

set rootview controller first

remove that code

[self.window addSubview:navigationController.view];

and include

self.window.rootViewController = navigationController;

in present modal view controller u can try like this

    yourview *detailViewController = [[yourview alloc] initWithNibName:@"yourview" bundle:nil];
         UIBarButtonItem *doneButton = [[UIBarButtonItem alloc ] initWithBarButtonSystemItem:UIBarButtonSystemItemCancel target:self action:@selector(dismiss)];
     detailViewController.navigationItem.leftBarButtonItem = doneButton;
        UINavigationController *nav;
        nav=[[[UINavigationController alloc] initWithRootViewController:detailViewController] autorelease];
        [self presentModalViewController:nav animated:YES];
        [detailViewController release];
[doneButton release];

-(void) dismiss
{
      [self dismissModalViewControllerAnimated:YES];
  }