this class is not key value coding-compliant for the key imageView

Question

I have a problem with the RootViewController of my application. When I run the app I get this error. What do it means?

  NSUnknownKeyException', reason: '[<UIApplication 0x8634010> setValue:forUndefinedKey:]:     this class is not key value coding-compliant for the key bigImageView.'
 First throw call stack:
 (0x1992012 0x1357e7e 0x1a1afb1 0xe04711 0xd85ec8 0xd859b7 0xdb0428 0x4bc0cc
 0x136b663 0x198d45a 0x4babcf 0x4bc98d 0x29eceb 0x29f002 0x29ded6 0x2af315 0x2b024b 
 0x2a1cf8 0x1dbedf9 0x1dbead0 0x1907bf5 0x1907962 0x1938bb6 0x1937f44 0x1937e1b 0x29d7da 0x29f65c 0x2c6d 0x2b95)   
 libc++abi.dylib: terminate called throwing an exception

My code in RootViewController.h

  #import <UIKit/UIKit.h>


  @interface RootViewController : UIViewController <UIGestureRecognizerDelegate>{

  }

 @property (nonatomic, copy)IBOutlet UIImageView * bigImageView;
 @property (nonatomic, assign)BOOL fromRootViewController;


 - (void)handleTap:(UITapGestureRecognizer *)recognizer;



 @end

My code in RootViewController.m

   #import "RootViewController.h"
   #import "MenuViewController.h"

  @interface RootViewController ()

   @end

  @implementation RootViewController

  @synthesize bigImageView;
  @synthesize fromRootViewController;

  - (void)viewDidLoad
   {
        [super viewDidLoad];
         UIDeviceOrientation deviceOrientation = [[UIDevice currentDevice]orientation];

          if(deviceOrientation == UIInterfaceOrientationPortrait || deviceOrientation==    UIInterfaceOrientationPortraitUpsideDown) {
    self.bigImageView= [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"milanocina_V.png"]];

}
else if (deviceOrientation== UIInterfaceOrientationLandscapeRight){
   self.bigImageView  = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"milanocina_O.png"]];

}
else if (deviceOrientation==UIInterfaceOrientationLandscapeLeft){

    self.bigImageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"milanocina_O.png"]];



}

[self.view addSubview:self.bigImageView];

UITapGestureRecognizer * recognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleTap:)];
recognizer.delegate = self;
[self.view addGestureRecognizer:recognizer];

}

The RootViewController initially called ViewController and I've changed the name. Can be correlated with error? What can I do?

Answer 1

At some point, you set a @property. You then deleted it from your code but didn't unhook it in your xib/storyboard. You need to find it in your storyboard, rightclick it, and delete the outlet.

Answer 2

Here's another possibility: You renamed your class, but forgot to change your UIViewController initialization code. For me, it was this:

NewViewController *vc;
vc = [[NewViewController alloc] initWithNibName:@"OldViewController" bundle:nil];

Once I replaced the string @"OldViewController" with @"NewViewController", the problem went away.