Question

I have Building CCNode

It’s have property:

in .h file

@property (nonatomic) int testProperty;

in .mm file add tag and set property

[[GB2ShapeCache sharedShapeCache] addShapesWithFile:@"Objects.plist"];
[CCTexture2D PVRImagesHavePremultipliedAlpha:YES];
[CCTexture2D setDefaultAlphaPixelFormat:kCCTexture2DPixelFormat_RGBA8888];
batchNode = [CCSpriteBatchNode batchNodeWithFile:@"sprite.png"];
[self addChild:batchNode];
[[CCSpriteFrameCache sharedSpriteFrameCache]addSpriteFramesWithFile:@"sprite.plist"];
sprite = [CCSprite spriteWithSpriteFrameName:[NSString stringWithFormat:@"%@.png", type]];
[batchNode addChild:sprite];
[sprite setTag:2];                 //SET TAG
[self setTestProperty:10];         //SET PROPERTY
...

Also is the ContactListener class
It’s work correctly with this code and i’m detecting body by tag fine:

#import "ContactListener.h"
#import "Building.h"

void ContactListener::BeginContact(b2Contact* contact)
{
    b2Body* bodyA = contact->GetFixtureA()->GetBody();
    b2Body* bodyB = contact->GetFixtureB()->GetBody();

    Building *buildA = (Building *)bodyA->GetUserData();
    Building *buildB = (Building *)bodyB->GetUserData();
    if (buildA.tag == 2) {
        NSLog(@"Collision with building");
    }
}

PROBLEM:
I don understand how get property from ContactListener

I tried to get it so:

if (buildA.tag == 2) {
            NSLog(@"Collision with building");
            NSLog(@"testProperty == %i", buildA.testProperty);
        }

But buildA.testProperty not work, and get error

Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[CCSprite testProperty]: unrecognized selector sent to instance 0x434af0'

If your can explain my please how get property from this class. Thanks.

Answer 1

When I create body, I set into user data sprite.

In the Building.h

body->SetUserData(self);

solved the problem.