Why can't I retain a UIView-Pointer?

Question

I'm trying to pass a UIView to another class - which kinda works, but I can't retain the pointer...

in my .h file I declare the view:

UIView *someView;

I add the property

@property (nonatomic, retain) UIView *someView;

And in the .m-file I synthesize the property

@synthesize someView;

Then I have a method to set the view (which is set in the .h file as well - believe me :):

-(void)makeViewPointer:(UIView *)myView{
    someView = [[UIView alloc] init];
    someView = myView;

    for(UIView *aView in someView.subviews){

        NSLog(@"tag %d", aView.tag);

    }
}

So far, everything's working. When I log the someView, I get a pointer and all the subviews are accessable.

I'm calling this method from another class - which seems to work fine.

NOW - I have an IBAction set up to do something with that view after a button is clicked

-(IBAction)doSomething:(id)sender{
    NSLog(@"show the view %@", someView);

    for(UIView *aView in someView.subviews){  // doesn't output anything

        NSLog(@"tag %d", aView.tag);

    }

}

At this point, the someView-var is empty again - WHY????

I assumed, that when I use @property (nonatomic, retain), the variable gets retained automatically?

I also tried to retain the variable upon initializing:

someView = [[UIView alloc] retain];

doesn't work

or

someView = [[UIView alloc] init];
[someView retain];

doesn't work either...

What on earth am I doing wrong???

Thanks for any help!

Answer 1

Few things.

someView = [[UIView alloc] init];
someView = myView;

The above is wrong. First you're creating a new UIView instance and assigning it to someView. You then assign myView to someView. This is causing a memory leak, because you never released someView, you just reassigned it.

I think what you're trying to do is this:

[someView release];
someView = [myView retain];

You then have to make sure you release someView when you're completely finished with it.

This is what the @property (nonatomic, retain) will do, but to use that you have to do:

[self setSomeView:myView];

Answer 2

If you don't use the self-dot notation then you don't retain the object assigned to the property.

You need to use:

self.someView = myView;

and

for(UIView *aView in self.someView.subviews){

The self notation calls the synthesized accessor methods that manage retention. If you don't use self, nothing is retained properly.

Answer 3

OK - I guess, I did everything as wrong as possible ;)

I should've mentioned, I guess, that I had set up the views in IB. There, I added my class I was talking about, to my parent-view (sounds confusing, I know - but, hey, it's IB :)...

The goal was to have some sort of overlay-view pop up - but I didn't wanted to put that view in a separate nib-file. So, that's why I just added the class from the classes-library.

I finally gave up now and moved the overlay to a separate nib, made my class a view-controller and... everything works fine...

Thanks for the hints anyway, guys - I did learn a good bit...