Question

does this retain my subview twice?

- (void)viewDidLoad
{
CGRect frame=CGRectMake(0, 0, 320, 460);
mapButtons*newButtons=[[mapButtons alloc] initWithFrame:frame];
self.mapButtons=newButtons;
[newButtons release];

[self.view addSubview:self.mapButtons];

[self.mapButtons addButtons:@"yo"];

once it is added to the view hierarchy with addSubview, does it get an additional retain count beyond that retained by the ivar, self.mapButtons?

i want to be able to manipulate this subview easily, hence the ivar; is this a good way, or is there a better way?

Answer 1

EDIT
You mention memory-wise so I think it may need some clearing up. Each object has a retain count which is incremented with retain and decremented with release. When the retain count reaches 0 a dealloc message is sent. So when you put an additional retain on an object you are not using anymore memory you are simply incrementing the counter and not doing any kind of duplication.

There are a couple of ways you can grab a reference to a view but the way you are doing it is a good way. An alternative would be to tag the view and retrieve it from self.view using

UIView *view = [self.view viewWithTag:tagId];

I prefer the ivar way e.g. how you have done it (this will change when ARC comes in) but I tend not to worry about the the actual retain count of an object. I concentrate on balancing my retain/releases.

Therefore I use the rule that if it’s a local variable I try as far as possible to match my retain/release’s within the scope it is defined in. The exception being ivar which are released in dealloc