Objective C error: [BodyObject alloc]: unrecognized selector sent to instance

Question

I have been trying to use some objective C, i have got as far as creating a couple of objects and im now trying to instantiate them. The code compiles with no warnings but when it runs i get this in the console:

*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason:
'-[CCSprite copyWithZone:]: unrecognized selector sent to instance 0x6424ad0'

Im guessing there is just a problem with the code somewhere, im not calling a copyWithZone method anywhere

Here is the code for game object:

gameobject.h

#import "cocos2d.h"
#import "Box2D.h"

@interface GameObject : NSObject {

    }

-(id) initWithSprite:(CCSprite*) sprite
         andVelocity:(b2Vec2*) velocity;

@property (nonatomic, copy) CCSprite *Sprite;
@property (nonatomic) b2Vec2 *Velocity;

@end

gameobject.mm

#import "cocos2d.h"
#import "GameObject.h"
#import "Box2D.h"

@implementation GameObject

@synthesize Sprite;
@synthesize Velocity;

-(id) initWithSprite:(CCSprite*) sprite
         andVelocity:(b2Vec2*) velocity
{
    self = [super init];

    self.Sprite = sprite;
    self.Velocity = velocity;

    return self;
}

@end

here is the code for BodyObject:

BodyObject.mm

#import "BodyObject.h"


@implementation BodyObject

@synthesize Body;
@synthesize Fixture;

-(id) initWithBody:(b2Body*) body 
        andFixture:(b2Fixture*) fixture 
       andVelocity:(b2Vec2*) velocity 
         andSprite:(CCSprite*) sprite
{
    self = [super initWithSprite:(CCSprite*)sprite 
                     andVelocity:(b2Vec2*)velocity];

    self.Body=body;
    self.Fixture=fixture;

    return self;
}

@end

BodyObject.h

#import "GameObject.h"
#import "Box2D.h"
#import "cocos2d.h"

@interface BodyObject : GameObject {

}

@property (nonatomic) b2Body *Body;
@property (nonatomic) b2Fixture *Fixture;

-(id) initWithBody:(b2Body*) body 
        andFixture:(b2Fixture*) fixture 
       andVelocity:(b2Vec2*) velocity
         andSprite:(CCSprite*) sprite;

@end

And where im trying to instantiate it

BodyObject *bodyObject = [[BodyObject alloc] initWithBody:(b2Body *)body 
                                               andFixture:(b2Fixture *)fixture 
                                              andVelocity:(b2Vec2*) vector 
                                                andSprite:(CCSprite*) sprite];

Can anyone point me as to where to start looking for the solution for these types of errors or see a problem with the code? I can post more of the classes if required.

Thanks,

Answer 1

This is wrong: self = [[super initWithSprite:(CCSprite*)sprite andVelocity:(b2Vec2*)velocity] alloc];

The right procedure is: self = [super initWithSprite:(CCSprite*)sprite andVelocity:(b2Vec2*)velocity];

Answer 2

If you've reached the point in your code where your custom init methods are being called, then your object has already been allocated, so remove those outer calls to +alloc altogether.

(Also, unrelated, but the convention when naming selectors is not to include works like and, or, and but. Something like -initWithSprite:velocity: would conform to the Cocoa naming conventions.)

Answer 3

The likely reason for this crash is the CCSprite does not conform to NSCopying. If you either implement NSCopying on CCSprite (providing a copyWithZone: method) or change your Sprite property to retain, this crash will stop.

As a side note, accepted Objective-C style frowns upon any variable starting with a capital letter.