Can't get correct int value from fetching core data in iOS

Question

I found a weird problem when fetching data from core data, the data i insert into core data is an Event object, the title, desc and localTime can be shown correctly.

However, the localUTC , an int type value, for example, I insert -2 into core data, but after fetching, it becomes -30. The more weirder thing is, in the instance of Event class, the value of localUTC is -2, but when displaying it in UITextField , it becomes -30

the code i'm using is list below:

Event *event = [[utility getAllEvents] lastObject];
NSLog(@"%@", event); // log 1

_eventTitle.text = event.title;
_eventDesc.text = event.desc;
_eventTime.text = [NSString stringWithFormat:@"%@", event.localTime];
NSLog(@"%d", event.localUTC); // log 2
_eventUTC.text = [NSString stringWithFormat:@"%d", event.localUTC];
NSLog(@"%@", event); // log 3
NSLog(@"%d", event.localUTC); // log 4

The logs:

2015-01-21 20:13:21.186 EventTest[3695:248822] <NSManagedObject: 0x7fe22a445c60> (entity: Event; id: 0xd000000000200000 <x-coredata://BC13045B-499A-4DE6-828F-3BACCFF56CF0/Event/p8> ; data: <fault>) // log 1: NSLog(@"%@", event); 

2015-01-21 20:13:21.188 EventTest[3695:248822] -30 // log 2: NSLog(@"%d", event.localUTC);

2015-01-21 20:13:21.189 EventTest[3695:248822] <NSManagedObject: 0x7fe22a445c60> (entity: Event; id: 0xd000000000200000 <x-coredata://BC13045B-499A-4DE6-828F-3BACCFF56CF0/Event/p8> ; data: {
    desc = "abcdefg\n\nhhhh\n\nxx\nsd\nd\nfsad\nf";
    localTime = "2015-01-21 08:56:31 +0000";
    localUTC = "-2";
    title = "New event111";
}) // log 3: NSLog(@"%@", event); --NOTICE, the value of localUTC is "-2", but when display, it becomes -30

2015-01-21 20:13:21.189 EventTest[3695:248822] -30 // log 4: NSLog(@"%d", event.localUTC); 

UPDATE

the code Event *event = [[utility getAllEvents] lastObject];

was cast from NSManagedObject, is this the problem? [utility getAllEvents] returns NSArray of NSManagedObject (should be). I'm a noob of Core Data, now sure if this causes the problem.

UPDATE 2 The problem is fixed by using this code:

[_eventUTC setText:[NSString stringWithFormat:@"%@", [event valueForKey:@"localUTC"]]];

but I don't know why it solves the problem, anyone can point it out?

Answer 1

Even though the core data model (your .xcdatamodeld file) has attributes such as Integer 16 / 32 /64 the values are stored in a NSNumber object. Therefore you need to access your number values via the NSNumber object.

Answer 2

If you look carefully at the output of NSLog(@"%@", event); you will see that localUTC is a NSString :

localUTC = "-2";

In your another log statement you use %d format specifier , which is used for integer types, not strings.

NSLog(@"%d", event.localUTC);

Change this to

NSLog(@"%@", event.localUTC);

or, if you are interested in the integer value

NSLog(@"%d", [event.localUTC integerValue]);