Question

I created a brand new project and created a new view controller with a button in the view.

I am adding the view in application:didFinishLaunchingWithOptions

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    // Override point for customization after application launch.
    self.window.backgroundColor = [UIColor whiteColor];


    BOOL introDisplayed = [[NSUserDefaults standardUserDefaults] boolForKey:kIntroScreenSeenByUser];

    if(introDisplayed)
    {

    }
    else 
    {
        IntroView *introView = [[IntroView alloc] initWithNibName:@"IntroView" bundle:nil];
        [self.window addSubview:introView.view];
    }

    [self.window makeKeyAndVisible];

    return YES;
}

.h file

@interface IntroView : UIViewController 


@property (weak, nonatomic) IBOutlet UIButton *clickMe;
- (IBAction)clicked:(id)sender;

@end

.m file

#import "IntroView.h"

@interface IntroView ()
@end

@implementation IntroView
@synthesize clickMe;

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Custom initialization
    }
    return self;
}

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view from its nib.
}

- (void)viewDidUnload
{
    [self setClickMe:nil];
    [super viewDidUnload];
    // Release any retained subviews of the main view.
    // e.g. self.myOutlet = nil;
}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    return (interfaceOrientation == UIInterfaceOrientationPortrait);
}

- (IBAction)clicked:(id)sender {
    NSLog(@"clicked");
}
@end

Clicking on the button results in a EXC_BAD_ACCESS(code=2 error. Any ideas? I am using ARC.

Thanks

UPDATE

Created a public property on the application delegate called “introViewController” and changed the application:didFinishLaunchingWithOptions

@synthesize introViewController;

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    // Override point for customization after application launch.
    self.window.backgroundColor = [UIColor whiteColor];


    BOOL introDisplayed = [[NSUserDefaults standardUserDefaults] boolForKey:kIntroScreenSeenByUser];

    introViewController = [[IntroView alloc] initWithNibName:@"IntroView" bundle:nil];
    if(introDisplayed)
    {

    }
    else 
    {
        [self.window addSubview:introViewController.view];
    }

    [self.window makeKeyAndVisible];

    return YES;
}

This solved the error.

Answer 1

You’re creating your IntroView controller, and adding it’s view as a subview, but the controller itself is released. I don’t think that adding the view controller’s view (and then letting ARC discard the controller itself) is an acceptable way to create a view.

Perhaps you could make the IntroView view controller a property of the app delegate class and therefore it won’t be released by ARC.

Personally, I don’t monkey around with the app delegate’s creation of the views and controllers, but rather I let my target settings and my NIBs dictate that. I presume you’re doing this because you want to have some intro screen. If I wanted an screen, I’d have my main view controller go ahead and present whatever intro I want. That way when the intro is dismissed (or popped off, depending upon whether you pushed or presented modally), my main view controller is still at the top (and useful methods like popToRootViewController work perfectly).