retain property points to wrong address

I have singleton class with ivar named formatter. There is some code:

@interface SettingsController : NSObject {

    NSDateFormatter *formatter;  
}

@property (nonatomic,retain,readwrite)  NSDateFormatter *formatter;




@implementation SettingsController

@synthesize formatter,;

SYNTHESIZE_SINGLETON_FOR_CLASS(SettingsController);

-(id)init
{
 if ( (self = [super init]) )
  {
        ...
        self.formatter = [[[NSDateFormatter alloc] init] autorelease];
        ...
  }

Problem is that sometime when I try to get this formatter that how:

[[SettingsController sharedSettingsController] formatter]

The value is missed. There NSDate,NSString or even my own class instance at address that formatter points.

I've try use [[NSDateFormatter alloc] init] but only [[[NSDateFormatter alloc] init] retain] make problem disappear.

How could it be, when I use @property (nonatomic,retain,readwrite) and never reset this ivar to another value?

EDITE: A开发者_JS百科fter I made subclass for NSDateFormatter, I've clearly and easy seen the release that make fall app. Thanks a lot to progrmr!

You write about class SettingsController, but are using class SyncProgress. Which is it?

If you properly @synthesized the @property, what you did in the init method you show should be correct, assuming you don't release the property -- or at least the same object, from whatever reference to it you may have -- later on, either in the same method or elsewhere. In other words, don't release an autoreleased item.

FWIW, the article that describes the macro says that you should declare

+ (SettingsController *) sharedSettingsController;

I can't see you doing that, so did you?

And you are using class SyncProgress, not SettingsController. Assuming you declared that as singleton too, you should do the same for SyncProgress:

+ (SyncProgress *) sharedSyncProgress; 

What is the init method for SyncProgress? Do you set the formatter there too, and does it even have one? Or are you just looking at the wrong class?