Question

II wanted to add a UIBarButton to my UINavigationController. I did that with the help of following code,

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    UIViewController *rootController = [[RootViewController alloc] initWithNibName:@"RootViewController" bundle:nil];

    self.navigationController = [[UINavigationController alloc] initWithRootViewController:rootController];

    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    [self.window addSubview:navigationController.view];
    [self.window makeKeyAndVisible];
    return YES;
}


- (void)viewDidLoad
{
    [super viewDidLoad];

    UIBarButtonItem *addInfoButton = [[UIBarButtonItem alloc] initWithTitle:@"Add Info" style:UIBarButtonItemStylePlain target:self action:@selector(addCustomerInfo)];
    self.navigationItem.rightBarButtonItem = addInfoButton;
}

-(void) addCustomerInfo
{
    AddInfoViewController *addVC = [[AddInfoViewController alloc] initWithNibName:@"AddInfoViewController" bundle:nil];

    [addVC setModalTransitionStyle:UIModalTransitionStyleCoverVertical];

    [self presentModalViewController:addVC animated:YES];
}

Should I declare “-(void) addCustomerInfo” in .h file? I already tried that but no luck.

The code still throws the exeption,

2012-08-06 04:16:22.200 TableView[5698:f803] -[RootViewController addCustomerInfo]: unrecognized selector sent to instance 0x6c662b0
2012-08-06 04:16:22.202 TableView[5698:f803] * Terminating app due to uncaught exception ‘NSInvalidArgumentException’, reason: ‘-[RootViewController addCustomerInfo]: unrecognized selector sent to instance 0x6c662b0’

Answer 1

The code for your class is correct. You need to change your App Delegate

I suggest creating a property in your App Delegate to store your navigation controller –@property (strong, nonatomic) UINavigationController *navController; – Don’t forget to synthesize it.
Then, when you create your Navigation controller, set it to your property – self.navController = [[UINavigationController alloc] init];

This will guarantee your NavigationController is properly retained and that it can be accessed correctly by other classes in your application.

Below some sample code that might make it clearer:

First the AppDelegate header file:

//AppDelegate.h
#import <UIKit/UIKit.h>


@interface AppDelegate : UIResponder <UIApplicationDelegate>
{
    UINavigationController *navController;
}
@property (strong, nonatomic) UIWindow *window;
@property (strong, nonatomic) UINavigationController *navController;    
@end

And the implementation file:

//  AppDelegate.m
#import "AppDelegate.h"
@implementation AppDelegate
@synthesize window = _window;
@synthesize navController;
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    self.navController = [[UINavigationController alloc] init];    
    UIViewController *myVC= [[myVC alloc]     init];
    [self.navController pushViewController:myVC animated:NO];
    [self.window addSubview:navController.view];
    [self.window makeKeyAndVisible];
    return YES;
}