Hi,
This is from Apple Sample Code so I thought something as fundamental as this
would have been dealt with correctly. This is the copy method inside the
“ImageAndTextCell” class,
-(id) copyWithZone:(NSZone*) zone
{
ImageAndTextCell *cell = (BJImageAndTextCell*) [super copyWithZone:zone];
cell.pTextCellImage = self.pTextCellImage;
return cell;
}
I’ve changed the property to use the copy attribute instead of retain:
@property (nonatomic,copy) NSImage*
pTextCellImage;
Is this implementation correct? If not what should it be? Something like this?
- (instancetype)initTextCell:(NSString*) theInitialString
{
self = [super initTextCell:theInitialString];
if (self == nil)
return nil;
self.pTextCellImage = nil;
[self setFont:[NSFont systemFontOfSize:[NSFont smallSystemFontSize]]];
return self;
}
-(id) copyWithZone:(NSZone*) zone
{
ImageAndTextCell *cell = [[[self class] alloc] initTextCell:[self stringValue]];
cell.pTextCellImage = self.pTextCellImage;
return cell;
}
Cheers
Dave
> On 28 May 2015, at 00:25, Graham Cox <graham....@bigpond.com> wrote:
>
>
>> On 28 May 2015, at 12:56 am, Dave <d...@looktowindward.com> wrote:
>>
>> myCell = (ImageAndTextCell*) [cell copy];
>> //*******************************************************************************************************************
>
>
> It’s a “well known”* fact that a copy of an NSCell or any subclass thereof
> basically doesn’t work. You have to override -copyWithZone: and Do It
> Properly™, which means NOT calling super’s implementation first (which
> internally uses NSCopyObject()). I suspect that’s the root cause of your
> issue.
>
>
> * I say “well known” in quotes because it’s something that lurks there in the
> frameworks but is never spelt out in documentation, and almost every Mac OS
> developer comes up against it at some point and has to relearn this fact for
> themselves. This is your turn.
>
> —Graham
>
>
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