Re: Instance an from an NSString Class name
Re: Instance an from an NSString Class name
- Subject: Re: Instance an from an NSString Class name
- From: Seth Willits <email@hidden>
- Date: Tue, 21 Sep 2010 22:07:05 -0700
On Sep 21, 2010, at 9:21 PM, email@hidden wrote:
> NSString *class = [NSString stringWithCString:[data bytes] encoding:NSASCIIStringEncoding];
> Class obstacle = NSClassFromString(class);
> id thisObstacle = [[obstacle alloc] initWithImage:[sender draggedImage] andLocation:[sender draggingLocation]];
> [m_obstacles addObject:thisObstacle];
>
> I don't think I have to retain thisObstacle as m_obstacles take ownership.
No, but you'd better release it after you add it to the array otherwise you're leaking it. There's no such thing as "taking ownership" in an exclusive sense. m_obstacles simply retains it when you added it to the array. But the retain count is already 1 from the alloc, so now it's at +2. If you remove it from the array it's at +1 forever. You need to balance that alloc.
> However, must I retain [sender draggedImage] so the code becomes:
>
> NSString *class = [NSString stringWithCString:[data bytes] encoding:NSASCIIStringEncoding];
> Class obstacle = NSClassFromString(class);
> id thisObstacle = [[obstacle alloc] initWithImage:[[sender draggedImage] retain] andLocation:[sender draggingLocation]];
> [m_obstacles addObject:thisObstacle];
Also no. The obstacle would retain it, if needed, as Jerry said.
--
Seth Willits
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