CODEWITHSUNDEEP
objective-ccore-datansmanagedobject
stefanr
stefanr

Reputation: 111

[NSManagedObject sayHello]: unrecognized selector sent to instance 0x

I try to extend NSManagedObject. Using XCode I created MyBox.m and MyBox.h (directly from the xcdatamodel file).

Then I modified these files:

#import <Foundation/Foundation.h>
#import <CoreData/CoreData.h>


@interface MyBox : NSManagedObject

@property (nonatomic, retain) NSDate * endDate;
@property (nonatomic, retain) NSNumber * globalId;
@property (nonatomic, retain) NSString * name;
@property (nonatomic, retain) NSDate * startDate;

-(NSString *)sayHello;

@end

and

#import "MyBox.h"
@implementation MyBox

@dynamic endDate;
@dynamic globalId;
@dynamic name;
@dynamic startDate;

-(NSString *)sayHello {
    return @"hello";
}  

@end

I can fetch all myBoxes

NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
    NSEntityDescription *entity = [NSEntityDescription
                                   entityForName:@"MyBox" inManagedObjectContext:context];
    [fetchRequest setEntity:entity];

NSMutableArray *myBoxes = [context executeFetchRequest:fetchRequest error:&error];

but later I call

MyBox *myBox = [myBoxes objectAtIndex:indexPath.row];    
    [myBox sayHello];

it compiles but then I get 

Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[NSManagedObject sayHello]: unrecognized selector sent to instance 0x8e73fc0'

If I only read a value like

NSLog(@"%@", myBox.name);

it works

I found similar problems here, but no solution. Thanks for your help.

Upvotes: 10

Views: 7895

Answers (5)

Au Room
Au Room

Reputation: 143

For Swift 5.0

This issue is present when you create the CoreData object in this way:

let object = CoreDataClass()
print(object.someProperty) // this is emit crash

Upvotes: 2

Mochi
Mochi

Reputation: 1117

Wrong Xcdatamodel.

I had the wrong xcdatamodel. It's a super dumb mistake but when you assume the latest model is 27 but your coworker changed it to 28 and you added your properties to model 27, it happens.You get these kind of errors and you assume it's something wrong with your Core Data model but it's simply your xcdatamodel number.

Gotta love programming =_=.

Upvotes: 0

jeremywhuff
jeremywhuff

Reputation: 2980

I had the right class name set in xcdatamodeld, but I didn't include the class's .m file in my target. I had to click on the .m on the left sidebar, then check the correct box on the right sidebar under Target Membership.

Upvotes: 0

Alexander Vasenin
Alexander Vasenin

Reputation: 13053

I've just got the same issue. Solved it by changing class name to the name of my NSManagedObject subclass in myApp.xcdatamodeld -> configurations -> default -> entities -> myEntity.

Upvotes: 21

Drewsmits
Drewsmits

Reputation: 1374

Assuming you have set the class name correctly on the MyBox entity, I would guess that the app has an older version of your Core Data managed object model. Clean your build and delete the app on the simulator/device for good measure. To be 100% sure, also delete your derived data folder.

If it doesn't work after that, I'll bet that you haven't set the entity class name correctly. Print out your NSEntityDescription and make sure it is what you expect.

Upvotes: 3

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