Question

Well
I have some troubles with initialisation class properties in objective c. I have read a lot information but I didn’t find answer to my question.
So I give example.
1)

//Ex_1.h
@interface Ex_1: UIView {
   IBOutlet UIButton *playBut;
}

@property(retain, nonatomic) IBOutlet UIButton *playBut;
-(void) method1;

@end

//Ex_1.m
@implementation Ex_1
@synthesize playBut;

-(id) initWithFrame:(CGRect)frame {
  self = [super initWithFrame : frame];
  if (self != nil)
      playBut = [UIButton buttonWithType:UIButtonTypeRoundedRect]; //retainCount of playBut = 1;
  return self;

}

-(void) method1 {
   [playBut setTitle:@"pause" forState:UIControlStateNormal];
}

@end

I main Programm first I init object of Ex_1 and then after some times call method1 of this object ([object method1]) and I get runtime error(error tells me that playBut is dealloc, but I think playBut’s retain count = 1).
So I have some questions:

1. Is it possible ?
2. Why garbage collector dealloces playBut if its retain count = 1?(because I don’t call [playBut release];
3. How do I init class properties?

I familar with C++ and actionScript, but I see first time in my life that garbage collector dealloced class property.
I use non ARC.
It is important for me.
Thanks for your attention and answers.

Answer 1

[UIButton buttonWithType:] returns an autoreleased object. It will be alive for the lifetime of the scope in which you call it, i.e. initWithFrame: but the autorelease pool can reclaim it after that. You should instead say, in your init selector:

playBut = [[UIButton buttonWithType:UIButtonTypeRoundedRect] retain];

Then send this in your dealloc:

[playBut release];

Now, if you were to add the playBut as a child to another UIView, that view would retain the child and you wouldn’t need to, as long as you only use it during the lifetime of the super view. This is a normal pattern. You could go further and assign a tag to playBut then use viewWithTag: to find your UIButton when you need it.