Should we point to an NSManagedObject entity with weak instead of strong pointer?

Posted by Jim Thio on Stack Overflow See other posts from Stack Overflow or by Jim Thio
Published on 2012-11-06T04:50:05Z Indexed on 2012/11/06 5:00 UTC
Read the original article Hit count: 190

Filed under:

objective-c

|

xcode

|

nsmanagedobject

I think because NSManagedObject is managed by the managedObject context the pointer should be weak.

Yet it often goes back to 0 in my cases.

    for (CategoryNearby * CN in sorted) {
        //[arrayOfItems addObject:[NSString stringWithFormat:@"%@ - %d",CN.name,[CN.order intValue]]];
        NearbyShortcutTVC * tvc=[[NearbyShortcutTVC alloc]init];
        tvc.categoryNearby =CN;
//        tvc.titleString=[NSString stringWithFormat:@"%@",CN.name];
//        tvc.displayed=CN.displayed;
        [arrayOfItemsLocal addObject:tvc];
        //CN

        PO(tvc);
        PO(tvc.categoryNearby);
        while (false);
    }
    self.arrayOfItems = arrayOfItemsLocal;

    PO(self.categoriesNearbyInArrayOfItems);
    [self.tableViewa reloadData];

...

Yet somewhere down the line:

tvc.categoryNearby becomes nil.

I do not know how or when or where it become nil.

How do I debug this? Or should the reference be strong instead?

This is the interface of NearbyShortcutTVC by the way

@interface NearbyShortcutTVC : BGBaseTableViewCell{

}
@property (weak, nonatomic) CategoryNearby * categoryNearby;

@end

To make sure that we're talking about the same object I print all the memory addresses of the NSArray

They're both the exact same object. But somehow the categoryNearby property of the object is magically set to null somewhere.

 self.categoriesNearbyInArrayOfItems: (
    0x883bfe0,
    0x8b6d420,
    0x8b6f9f0,
    0x8b71de0,
    0xb073f90,
    0xb061a10,
    0xb06a880,
    0x8b74940,
    0x8b77110,
    0x8b794e0,
    0x8b7bf40,
    0x8b7cef0,
    0x8b7f4b0,
    0x8b81a30,
    0x88622d0,
    0x8864e60,
    0xb05c9a0
)

self.categoriesNearbyInArrayOfItems: (
    0x883bfe0,
    0x8b6d420,
    0x8b6f9f0,
    0x8b71de0,
    0xb073f90,
    0xb061a10,
    0xb06a880,
    0x8b74940,
    0x8b77110,
    0x8b794e0,
    0x8b7bf40,
    0x8b7cef0,
    0x8b7f4b0,
    0x8b81a30,
    0x88622d0,
    0x8864e60,
    0xb05c9a0
)

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