iOS: EXC_BAD_ACCESS (code=2, address=0x42) - ios

Question

I have a class which should hold some data:
the header:
#import <Foundation/Foundation.h>
#class Behandler, Tag;
#interface OeffnungsZeit2 : NSObject
#property (nonatomic, retain) NSNumber * offen_stunde;
#property (nonatomic, retain) NSNumber * offen_minute;
#property (nonatomic, retain) NSNumber * geschlossen_stunde;
#property (nonatomic, retain) NSNumber * geschlossen_minute;
#property (nonatomic, retain) Tag *tag;
#property (nonatomic, retain) Behandler *behandler;
-(void)setTag:(Tag *)tag;
-(Tag *)getTag;
-(void)setBehandler:(Behandler *)behandler;
-(Behandler *)getBehandler;
#end
the main file:
#import "OeffnungsZeit2.h"
#import "Behandler.h"
#import "Tag.h"
#implementation OeffnungsZeit2
#dynamic offen_stunde;
#dynamic offen_minute;
#dynamic geschlossen_stunde;
#dynamic geschlossen_minute;
-(void)setTag:(Tag *)tag{
self.tag = tag;
}
-(Tag*)getTag{
return self.tag;
}
-(void)setBehandler:(Behandler *)behandler{
self.behandler = behandler;
}
-(Behandler*)getBehandler{
return self.behandler;
}
#end
When I try to access it, somewhere in these lines:
NSArray *tage = [self fetchTageWithNummer:openDay];
Tag *tag = [tage objectAtIndex:0];
// create an OeffnungsZeit2 object and add it to our array
OeffnungsZeit2 *oeffnungsZeit2 = [[OeffnungsZeit2 alloc] init];
[oeffnungsZeit2 setTag:tag];
oeffnungsZeit2.offen_stunde = [NSNumber numberWithInt:[openHours intValue]];
oeffnungsZeit2.offen_minute = [NSNumber numberWithInt:[openMins intValue]];
oeffnungsZeit2.geschlossen_stunde = [NSNumber numberWithInt:[closeHours intValue]];
oeffnungsZeit2.geschlossen_minute = [NSNumber numberWithInt:[closeMins intValue]];
[self.oeffnungsZeiten addObject:oeffnungsZeit2];
I am getting an ECX_BAD_ACCESS error.
Can anyone hint me, why this is wrong? I am pretty new to iOS, and never wrote a class which holds data...

Answer 1

It looks like you are getting a stack overflow error when your getters/setters call themselves. For example, this code
-(void)setTag:(Tag *)tag{
self.tag = tag;
}
is infinite recursion, because self.tag = tag is another syntax for writing [self setTag:tag].
If you are using the latest Xcode, all you need to do is dropping the declarations and definitions of the getters and setters for tag and behandler that you have added manually. The compiler will generate the code that is equivalent, but has no infinite recursion.
Note: there are legitimate cases when you need to access the variable that "backs" an automatically generated property. By convention, the name of that variable is the name of the property prefixed with an underscore. You can override this in the #synthesize directive for the property.