Question

I have an instance of UICollectionViewCell ( lets call it c ).
c has a property child of type B*

@property (strong) B* child;

in B there is a declaration

@property (strong) C* parent;

in C.m I set

self.child.parent = self

In B.m I have code :

position = self.parent.center.x;

For some reason I can not access center property of UIVIew from outside the instance. Is it private ? I looked in UIView.h and in the documentation. I dont see it being private.

Accessing self.parent in B.m is giving me the correct values …

So why cant I access it ? In C.m

self.center

is working as expected …

EDIT : With the real code

This is the so-called “C.h”

#import <UIKit/UIKit.h>
#import "UIMovableImage.h"

@interface LetterCollectionCell : UICollectionViewCell

@property (weak, nonatomic) IBOutlet UIImageView *letterCellView;

@end

This is “B.h”

#import <UIKit/UIKit.h>

@class LetterCollectionCell;

@interface UIMovableImage : UIImageView
{
    CGPoint currentPoint;
}
@property (strong) LetterCollectionCell* parent;

@end

This is “C.m”

#import "LetterCollectionCell.h"
#import "LettersCollection.h"

@implementation LetterCollectionCell

-(void)PrepareImage:(int)index Hint:(BOOL)hint Rotate:(BOOL)rotate
{
    if ([_letterCellView respondsToSelector:@selector(parent)])
    {
       UIMovableImage* temp = ((UIMovableImage*)self.letterCellView);
       temp.parent = self;
    }     
}    

@end

And here is the “B.m”

#import "UIMovableImage.h"
#import "LetterCollectionCell.h"

@implementation UIMovableImage

- (void) touchesMoved:(NSSet*)touches withEvent:(UIEvent*)event
{
        // Get active location upon move
        CGPoint activePoint = [[touches anyObject] locationInView:self.parent];

        // Determine new point based on where the touch is now located
        CGPoint newPoint = CGPointMake(self.parent.center.x + (activePoint.x - currentPoint.x),
                                       self.parent.center.y + (activePoint.y - currentPoint.y));

 }
@end

Please note that the LetterCollectionCell’s letterCellView is of type UIImageView and not of type UIMovableImage. The reason is that I want to keep this declaration as a placeholder. In the Interface Builder I have two scenes where the LetteCollection is used. In one scene I set the imageview to be of UIMovableImage ( thru Inspector Window ) and at the other I left the image to be of type UIImageView. So the run-time will create the proper class upon different scenes and at the collection I check : if the image has a property “parent” – I set it up. Otherwise I dont.
It works fine, the assignment works just fine…. but the access is not

Answer 1

I found the reason.
The whole question was barking at the wrong tree.
In fact, the bug was at the other place and I just kept looking at the “Invalid Expression” int the debugger’s watch window.

To sum up : accessing the “center” property worked just find under the circumstances described in the original question. The “Invalid Expression” of the debugger and a bug in a different place made me chase a wrong thing.

I +1d the generally correct answers and comments but can not accept them since it may mislead people.

Thanks to all for the help and the effort