CODEWITHSUNDEEP
iphoneuiviewcontrolleruinavigationcontroller
MrHappy19
MrHappy19

Reputation: 9

iPhone NavigationController Application

I am following the tutorial here to use a UINavigationController to switch between ViewControllers. If I download the code and follow the tutorial it works all fine and dandy, but when I try to apply this to different apps I encounter the following confusion/issue. When I am in the "FirstViewController" how do I access [self navigationController] if I do not have any navigationController in my viewController class? In this example, I cannot find out how or where the navigationController comes from in the FirstViewController. Can someone please explain how this works?

**Note: The full source code for the entire project can be found on the page I linked to above as well.

This is the line that confuses me:

[[self navigationController] pushViewController:secondViewController   animated:YES];

This is the entire code for the viewController:

.h

#import <UIKit/UIKit.h>
@class SecondViewController;

@interface FirstViewController : UIViewController {

    IBOutlet SecondViewController *secondViewController;
}

@property(nonatomic, retain) SecondViewController *secondViewController;

- (IBAction)PressMe:(id)sender;

@end

.m

#import "FirstViewController.h"
#import "SecondViewController.h"


@implementation FirstViewController

@synthesize secondViewController;

- (void)viewDidLoad {
    [super viewDidLoad];
    self.title = @"First View";
}

- (IBAction)PressMe:(id)sender
{
    [[self navigationController] pushViewController:secondViewController animated:YES]; //This line
}


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


@end

Upvotes: 0

Views: 70

Answers (3)

Rickye
Rickye

Reputation: 1021

If you are using IB (as you write in the code) right click the button, drag it to the SecondViewController and then select "Touch Up Inside"

Upvotes: 0

Gabrail
Gabrail

Reputation: 220

simply , you don't have any navigation controller, so you can't switch from view to another one with this 

[[self navigationController] pushViewController:secondViewController   animated:YES];

create navigation controller object in your FirstView and use it to move between views and in your PressMe method :

SecondViewController *secondView = [[secondView alloc] initWithNibName:@"SecondViewController" bundle:nil];
        [self.navigationController pushViewController:secondView animated:YES];
[secondView release];

Upvotes: 0

beyerss
beyerss

Reputation: 1352

From Apple's Documentation:

If the receiver or one of its ancestors is a child of a navigation controller, this property contains the owning navigation controller. This property is nil if the view controller is not embedded inside a navigation controller.

So you don't have to declare the navigation controller. If the current view controller was loaded onto a navigation controller then the line you are referencing will provide you with the current navigation controller

Upvotes: 1

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