Question

When implementing the UITextFieldDelegate in my ViewController class, the following error is thrown when entering the first character in the text field:

-[MyViewController respondsToSelector:]: message sent to deallocated instance...

So, I tried creating a separate class (inheriting only NSObject) and implementing UITextFieldDelegate. Guess what, it worked perfectly. However, that introduces some other problems as I have to do a lot of ugly cross-class-communication that I’d like to avoid. Here’s the relevant parts of my app delegate code:

@interface RMSAppDelegate : NSObject <UIApplicationDelegate,
                                      UITabBarControllerDelegate>

@property (nonatomic, retain) UIViewController* myViewController;

@end

@implementation MyAppDelegate

@synthesize myViewController;

- (BOOL)application:(UIApplication *)application
            didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    myViewController = [[MyViewController alloc]
                         initWithNibName:@"MyView" bundle:nil];
    [self.window setRootViewController:myViewController];
    [self.window makeKeyAndVisible];
    return YES;
}

@end

.. and here’s what is being displayed:

@interface MyViewController : UIViewController <UITextFieldDelegate>

@property (nonatomic, retain) IBOutlet UITextField* pinTextField;
- (void)viewDidLoad;

@end

@implementation MyViewController

@synthesize pinTextField;

- (void)viewDidLoad {
    // DOES NOT WORK (WHY?)
    //[pinTextField setDelegate:self];

    // WORKS, BUT I'D LIKE TO AVOID
    [pinTextField setDelegate:[[[MyTextFieldDelegate alloc] init] autorelease];

    [pinTextField becomeFirstResponder];
    [super viewDidLoad];
}

@end

And please, if you see any code (even off topic) that I could be doing better, leave a comment.

Answer 1

Okay, I finally solved this on my own. I have not changed the code. My NIB (.xib) was the culprit!

I thought that nested UIViewControllers was OK, and I still think they are in some cases (and maybe using another programmatic method). Anyway, I was initializing my class MyViewController with a NIB that in the Objects panel had a UIViewController as the first object.

I solved this by having the UIView as the first object in the Objects panel, and setting the File’s Owner to be the UIViewController instead.

Correct code, incorrect NIB. Thank you for your help.