Cannot add SKSpriteNode dynamically? - ios

Question

I'm adding SKSpriteNode dynamically on didBeginContact delegate method :
Here is my code
-(void)adBall
{
SKSpriteNode *obj = [[SKSpriteNode alloc]initWithImageNamed:#"ball.png"];
obj.physicsBody = [SKPhysicsBody bodyWithTexture:obj.texture size:obj.texture.size];
obj.position = CGPointMake(100, 100);
obj.name = OBSTACLE_KEY;
obj.physicsBody.categoryBitMask = BallCategory1;
obj.physicsBody.contactTestBitMask = GreenLineCategory | RedLineCategory ;;
obj.physicsBody.collisionBitMask = GreenLineCategory | RedLineCategory ;;
obj.physicsBody.affectedByGravity = YES;
obj.physicsBody.dynamic = YES;
obj.physicsBody.friction = 0.0f;
obj.physicsBody.linearDamping = 0.0f;
obj.physicsBody.restitution = 1.0f;
obj.physicsBody.allowsRotation = NO;
[obj.physicsBody applyForce:CGVectorMake(200, 300)];
}
-(void)didBeginContact:(SKPhysicsContact *)contact
{
SKPhysicsBody *firstBody, *secondBody;
if (contact.bodyA.categoryBitMask < contact.bodyB.categoryBitMask)
{
firstBody = contact.bodyA;
secondBody = contact.bodyB;
}
else
{
firstBody = contact.bodyB;
secondBody = contact.bodyA;
}
if ([firstBody.node.name isEqual: OBSTACLE_KEY] && ( [secondBody.node.name isEqual: BLACKLINE_KEY]))
{
[self adBall];
}
}
But cant appear in screen it just show ball at bottom and disappear.
and if add [self adBall]; in didMoveToView method than working fine.
So Plz tell me where I'm wrong here ?

Answer 1

You never run
[self addChild:obj];
inside your adBall method. Therefore the newly created sprite won't be added to the scene graph and naturally won't be drawn (it gets discarded at the end of the method).

Answer 2

Ok Done it.
as LearnCocos2D said that i didn't add [self addChild:obj]; i add that line but than it not working in didMoveToView than what i did is called method after some time.
Like :
dispatch_after(dispatch_time(DISPATCH_TIME_NOW,0.1 * NSEC_PER_SEC), dispatch_get_main_queue(), ^{
[self adBall];
});