cocos2d sprite标签未设置

Question

我正在使用以下内容来创建带有b2bodys的精灵 但是我无法设置sprite标签。为什么不是[精灵setTag：3];工作？

当我检测到与这些精灵之一的碰撞时，它表示精灵标记是0

     -(void) addNewSpriteAtPosition:(CGPoint)p
     {
     // CCLOG(@"Add sprite %0.2f x %02.f",p.x,p.y);
// Define the dynamic body.
//Set up a 1m squared box in the physics world
b2BodyDef bodyDef;
bodyDef.type = b2_dynamicBody;
bodyDef.position.Set(p.x/PTM_RATIO, p.y/PTM_RATIO);
b2Body *body = world->CreateBody(&bodyDef);

// Define another box shape for our dynamic body.
b2PolygonShape dynamicBox;
dynamicBox.SetAsBox(.5f, .5f);//These are mid points for our 1m box

// Define the dynamic body fixture.
b2FixtureDef fixtureDef;
fixtureDef.shape = &dynamicBox; 
fixtureDef.density = 2;
fixtureDef.friction = 0.2f;
body->CreateFixture(&fixtureDef);


CCNode *parent = [self getChildByTag:kTagParentNode];

//We have a 64x64 sprite sheet with 4 different 32x32 images.  The following code is
//just randomly picking one of the images
int idx = (CCRANDOM_0_1() > .5 ? 0:1);
int idy = (CCRANDOM_0_1() > .5 ? 0:1);
CCPhysicsSprite *sprite = [CCPhysicsSprite spriteWithTexture:spriteTexture_ rect:CGRectMake(32 * idx,32 * idy,32,32)];

[parent addChild:sprite];

[sprite setPTMRatio:PTM_RATIO];
[sprite setB2Body:body];
[sprite setPosition: ccp( p.x, p.y)];
     [sprite setTag:3];
     }