Push to UIViewController from a UITabBarItem - objective-c

Question

I encounter a problem using UITabBarItem and UIButton in my application. My button is inside a UITabBarItem. When I press it I want to be pushed to another controller to display a PDF.
Here is a piece of code that works in other cases :
- (void)viewDidLoad {
UIImage* imageButton = [UIImage imageNamed:#"pdf-button.png"];
UIButton *buttonPDF = [UIButton buttonWithType:UIButtonTypeCustom];
buttonPDF.frame = CGRectMake(SCREEN_WIDTH/2 - 100, 100, 200, 36);
[buttonPDF setImage:imageButton forState:UIControlStateNormal];
buttonPDF.contentMode = UIViewContentModeScaleAspectFit;
buttonPDF.contentHorizontalAlignment = UIControlContentHorizontalAlignmentFill;
[buttonPDF addTarget:self action:#selector(displayPDFParams:) forControlEvents:UIControlEventTouchUpInside];
[self.view addSubview:buttonPDF];
}
-(void)displayPDFParams:(UIButton *)sender {
PDFProduitController *pdfController = [[PDFProduitController alloc] init];
pdfController.pdf = documentParametres;
[self.navigationController pushViewController:pdfController animated:YES];
}
displayPDFParams is called but it not push me on my pdfController. I think it's because I'm not able to target the parent navigation controller of my application...
Anyone help would be much appreciated. Thanks in advance !

Answer 1

You need To initialize your root view controller with the navigation controller. Here is the code.
In your AppDelegate.h
#import <UIKit/UIKit.h>
#import "HomeViewController.h"
#class HomeViewController;
#interface IDSAppDelegate : UIResponder <UIApplicationDelegate>{
UINavigationController *nav;
}
#property (strong, nonatomic) HomeViewController *homeViewController;
#end
In your AppDelegate.m
#import "IDSAppDelegate.h"
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
self.homeViewController = [[HomeViewController alloc] initWithNibName:#"HomeViewController" bundle:nil];
nav=[[UINavigationController alloc]initWithRootViewController:self.homeViewController];
self.window.rootViewController = nav;
[self.window makeKeyAndVisible];
return YES;
}

Answer 2

Problem solved by define a property in my UIViewController (as UITabBarItem) like this :
#property (nonatomic, retain) UINavigationController *superNavController;
And set it in my UITabBarController :
self.myViewController.superNavController = self.navigationController;
Finally I modified my displayPDFParams method :
-(void)displayPDFParams:(UIButton *)sender {
PDFProduitController *pdfController = [[PDFProduitController alloc] init];
pdfController.pdf = self.documentParametres;
[self.superNavController pushViewController:pdfController animated:YES];
}
Works perfectly !