unrecognized selector sent to instance

Question

I am getting the following error message which I cannot understand why its happening because I am not using any UIImageView. Sometimes I get the same error but its a CALayer?!?

Its worth also mentioning that I have 2 nibs and 2 controllers and a base controller where this code resides.

EDIT:

This is the structure of my project

MainViewController & its nib - HomeViewController in nib

MainViewController-Landscape & its nib - HomeViewController-Landscape in nib

HomeViewControllerBase - no nib - Base class where all outlets and item configuration code exists. - Outlets are used by both child classes below. - Outlets are linked to controls in each of the main nibs.

HomeViewController - Inherits from HomeViewControllerBase

HomeViewController-Landscape - Inherits from HomeViewControllerBase

So whats happening is that the child class is trying to dealloc its base class (which has all the outlets in it). I have designed it this way to avoid duplication of code in the different orientation viewcontrollers.

@implementation MainViewController
- (void)orientationChanged:(NSNotification *)notification
{
    UIDeviceOrientation deviceOrientation = [UIDevice currentDevice].orientation;

    if (UIDeviceOrientationIsLandscape(deviceOrientation) && !isShowingLandscapeView)
    {
        [self presentModalViewController:self.landscapeViewController
                                animated:YES];

        isShowingLandscapeView = YES;
    }
    else if (UIDeviceOrientationIsPortrait(deviceOrientation) && isShowingLandscapeView)
    {
        [self dismissModalViewControllerAnimated:YES];
        isShowingLandscapeView = NO;
    }
}

- (id)init
{
    self = [super initWithNibName:@"MainViewController" bundle:nil];

    if (self)
    {
        isShowingLandscapeView = NO;
        self.landscapeViewController = [[[MainViewController_Landscape alloc]
                                            initWithNibName:@"MainViewController-Landscape" bundle:nil] autorelease];

        [[UIDevice currentDevice] beginGeneratingDeviceOrientationNotifications];
        [[NSNotificationCenter defaultCenter] addObserver:self
                                                 selector:@selector(orientationChanged:)
                                                     name:UIDeviceOrientationDidChangeNotification
                                                   object:nil];
    }

    return self;
}
@end

@implementation HomeViewControllerBase

    - (void)bestSellItemTapped:(id)sender
    {
        NSLog(@"best sell item tapped");
    }

    - (void)configureBestSellItems
    {
        [self startRetrievingRegions];

        // load all the images from our bundle and add them to the scroll view
        //  NSUInteger i;
        for (int i = 0; i <= 150; i++)
        {

            UILabel *itemTitle = [[UILabel alloc]initWithFrame:CGRectMake(0, 0, 100, 50)];
            itemTitle.text = @"Majorca";

            UILabel *itemPrice = [[UILabel alloc]initWithFrame:CGRectMake(0, 50, 100, 50)];
            itemPrice.text = @"£249";

            NSString *imageName = @"tempImage.jpg";
            UIImage *image = [UIImage imageNamed:imageName];


            UIButton *mainButton = [[[UIButton alloc]init] autorelease];

            [mainButton addTarget:self action:@selector(bestSellItemTapped:) forControlEvents:UIControlEventTouchUpInside];
            [mainButton setBackgroundImage:image forState:UIControlStateNormal];



            // setup each frame to a default height and width, it will be properly placed when we call "updateScrollList"
            CGRect rect = mainButton.frame;
            rect.size.height = kScrollObjHeight;
            rect.size.width = kScrollObjWidth;

            mainButton.frame = rect;
            mainButton.tag = i;


            [mainButton addSubview:itemTitle]; [itemTitle release];
            [mainButton addSubview:itemPrice]; [itemPrice release];




            [self.bestSellScrollView addSubview:mainButton];


        }

        [self layoutScrollImages];  // now place the photos in serial layout within the scrollview
    }


    // Implement viewDidLoad to do additional setup after loading the view, typically from a nib.
    - (void)viewDidLoad
    {
        [super viewDidLoad];
        [self configureBestSellItems];
    }

    - (void)layoutScrollImages
    {
        UIButton *view = nil;
        NSArray *subviews = [self.bestSellScrollView subviews];

        // reposition all image subviews in a horizontal serial fashion
        CGFloat curXLoc = 0;
        for (view in subviews)
        {
            if ([view isKindOfClass:[UIButton class]] && view.tag > 0)
            {
                CGRect frame = view.frame;
                frame.origin = CGPointMake(curXLoc, 0);
                view.frame = frame;

                curXLoc += (kScrollObjWidth + kScrollObjPadding);
            }
        }

        // set the content size so it can be scrollable
        [self.bestSellScrollView setContentSize:CGSizeMake((150 * kScrollObjWidth), 
                                                           [self.bestSellScrollView bounds].size.height)];
    }

@end

@interface HomeViewController : HomeViewControllerBase
@end

@interface HomeViewController_Landscape : HomeViewControllerBase
@end

@implementation HomeViewController

- (void)dealloc
{
    [super dealloc]; //When I remove this it works
}

@end

@implementation HomeViewController_Landscape

- (void)dealloc
{
   [super dealloc]; //When I remove this it works
}

@end

---

-[UIImageView bestSellItemTapped:]: unrecognized selector sent to instance 0x681c2b0 2011-04-12 15:45:26.665 [21532:207] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[UIImageView bestSellItemTapped:]: unrecognized selector sent to instance 0x681c2b0'
*** Call stack at first throw: (    0   CoreFoundation                      0x00dc85a9 __exceptionPreprocess + 185  1   libobjc.A.dylib                   0x00f1c313 objc_exception_throw + 44  2   CoreFoundation                    0x00dca0bb -[NSObject(NSObject) doesNotRecognizeSelector:] + 187  3   CoreFoundation                      0x00d39966 ___forwarding___ + 966   4   CoreFoundation                      0x00d39522 _CF_forwarding_prep_0 + 50   5   UIKit                             0x0001a4fd -[UIApplication sendAction:to:from:forEvent:] + 119    6 UIKit                               0x000aa799 -[UIControl sendAction:to:forEvent:] + 67  7   UIKit                               0x000acc2b -[UIControl(Internal)
_sendActionsForEvents:withEvent:] + 527     8   UIKit                         0x000ab7d8 -[UIControl touchesEnded:withEvent:] + 458     9   UIKit                               0x002ad4de
_UIGestureRecognizerSortAndSendDelayedTouches
+ 3609  10  UIKit                               0x002adc53
_UIGestureRecognizerUpdateObserver + 927    11  CoreFoundation                0x00da989b
__CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__
+ 27    12  CoreFoundation                      0x00d3e6e7 __CFRunLoopDoObservers + 295     13  CoreFoundation                0x00d071d7 __CFRunLoopRun + 1575  14  CoreFoundation                      0x00d06840 CFRunLoopRunSpecific + 208   15  CoreFoundation                    0x00d06761 CFRunLoopRunInMode + 97    16 GraphicsServices                    0x010001c4 GSEventRunModal + 217     17  GraphicsServices                    0x01000289 GSEventRun + 115     18  UIKit 0x00028c93 UIApplicationMain + 1160   19                      0x000027a9 main + 121   20 
                      0x00002725 start + 53 ) terminate called after throwing an instance of 'NSException'

Answer 1

Is the whatever ViewController this code is from still alive when the button is tapped? An error like this (unrelated object - UIImageView in this case) usually means you have a pointer to some area of the memory that has been released and reused for something else (UIImageView in this case).

Add an NSLog() printout to the -dealloc method of the view controller and make sure it's not fired before you tap the button.

Actually, add one more NSLog to the beginning of configureBestSellItems - NSLog(@"I am %x", self); (yes, %x, not %@). This will print out the address of your view controller - compare it with the address of the crashing object (as in "unrecognized selector sent to instance 0x681c2b0" - see if it prints "I am 0x681c2b0" initially)

Answer 2

If you are working with InterfaceBuilder and did some connecting / linking GUI-elements to IBActions / methods in the controllers header file right-click or "cntrl+click" that GUI-element that causes the error for being connected / linked to still existing methods only.

See `unrecognized selector sent to instance <OBJ_ADR>`after sending `dismissViewControllerAnimated:completion` to a UIViewController