ios/objective c/singleton: Storing userid in session variable

Question

I defined an NSInteger in a singleton (for userid) and access it in another class. However, while I have managed to get rid of error messages so it builds, the app crashes when

Answer 1

The following code using NSString instead of numbers and setting a local variable rather than a property works:

Session.h
@interface IDSession : NSObject
@property (readonly, copy) NSString *userid;
+ (IDSession *)sharedInstance;  
@end

Session.m
#import "IDSession.h"
@interface IDSession()
@property (readwrite,copy)NSString * userid;

@end

@implementation IDSession

+ (IDSession *)sharedInstance {
    static IDSession *session;
    if (!session){
        session = [[IDSession alloc] init];
        //include this class in other class and reference userid with [IDSession sharedInstance].userid
        NSString * userid = @"1";
    }
    return session;
}
@end
in retrieving class.

#import "session.h"

   NSString *userid =[Session sharedInstance].userid;
    NSLog(@"userid retrieved from session variable is %@",userid);