ccPhysicsCollisionPostSolve: method isn't called - cocos2d-iphone

Question

I just started using the SpriteBuilder with Cocos2d-v3
For the exercise of the SpriteBuilder, I practice in the tutorial of the following WebSite
for the time being.
https://www.makegameswith.us/tutorials/getting-started-with-spritebuilder/collision-detection/
As a flow of the games of the tutorials,at first the catapult and the catapultArm are located on stage,the object(Penguin) which was attached to the arm flies forward when I pull the arm to the rear with a finger and　separate a　finger from a screen.
When the object(Penguin) hits other objects(is called Seal),output log,"Something collided with a seal!"
In a "Implementing a delegate method" of tutorial, I was going to try to display a letter,"Something collided with a seal!" in Consoll using CCLOG method.
In the Gameplay.m, I implemented ccPhysicsCollisionPostSolve:seal:wildcard method that is called to dispaly a　letter "Something collide with a seal!",but this method isn't called when Penguin object hits other objects(seal).
I certainly made Penguin.ccbi and Seal.ccbi in SpriteBuilder,and thier ccbi file is Physics body.
Why ccPhysicsCollisionPostSolve:seal:wildcard method isn't called ?
It's my code that I really implemented as follows
This is Gameplay.m file
#import "Gameplay.h"
#implementation Gameplay{
CCPhysicsNode *_physicsNode;
//To joint betweent catapult and catapultArm
CCNode *_catapultArm;
CCNode *_catapult;
CCPhysicsJoint *_catapultJoint;
//Invisible Physics force
CCNode *_pullbackNode;
CCPhysicsJoint *_pullbackJoint;
//to move catapultArm
CCNode *_mouseJointNode;
CCPhysicsJoint *_mouseJoint;
//to fly penguin
CCNode *_currentPenguin;
CCPhysicsJoint *_penguinCatapultJoint;
//Object
CCNode *_levelNode;
//To Prevent a 'retry' button from moving with a fly penguin
CCNode *_contentNode;
}
//is called when CCB file has completed loading
-(void)didLoadFromCCB{
_physicsNode.collisionDelegate = self;
//tell this scene to accept touches
self.userInteractionEnabled = TRUE;
//loads the Levels/Leve1.ccb we have set up in SpriteBuilder
CCScene *level = [CCBReader loadAsScene:#"Levels/Level1"];
[_levelNode addChild:level];
//visualize physics bodies & joints
_physicsNode.debugDraw = TRUE;
//catapultArm and catapult shall not collide
[_catapultArm.physicsBody setCollisionGroup:_catapult];
[_catapult.physicsBody setCollisionGroup:_catapult];
//create a joint to connect the catapult arm with the catapult
_catapultJoint = [CCPhysicsJoint connectedPivoJointWithBodyA:_catapultArm.physicsBody
bodyB:_catapult.physicsBody
anchorA:_catapultArm.anchorPointInPoints];
//nothing shall collide with our invisible nodes
_pullbackNode.physicsBody.collisionMask = #[];
//nothing shall collide with our invisible nodes
_mouseJointNode.physicsBody.collisionMask = #[];
_pullbackJoint = [CCPhysicsJointconnectedSpringJointWithBodyA:_pullbackNode.physicsBody
bodyB:_catapultArm.physicsBody
anchorA:ccp(0,0)
anchorB:ccp(34,138)
restLength:60.f
stiffness:500.f
damping:40.f
];
}
//called on every touch in this scene (called every touch)
-(void)touchBegan:(UITouch *)touch withEvent:(UIEvent *)event{
CCLOG(#"touch Began");
CGPoint touchLcation = [touch locationInNode:_contentNode];
//start catapult dragging when a touch inside of the catapult arm occurs
if(CGRectContainsPoint([_catapultArm boundingBox], touchLcation))
{
//move the mouseJointNode to the touch position
_mouseJointNode.position = touchLcation;
_mouseJoint = [CCPhysicsJoint connectedSpringJointWithBodyA:_mouseJointNode.physicsBody
bodyB:_catapultArm.physicsBody
anchorA:ccp(0,0)
anchorB:ccp(34,138)
restLength:0.f
stiffness:3000.f
damping:150.f
];
//create a penguin from the ccbFile
_currentPenguin = [CCBReader load:#"Penguin"];
CGPoint penguinPosition = [_catapultArm convertToWorldSpace:ccp(34, 138)];
_currentPenguin.position = [_physicsNode convertToNodeSpace:penguinPosition];
//add it to the physics world
[_physicsNode addChild:_currentPenguin];
//we don't want the penguin to rotate in the scoop
_currentPenguin.physicsBody.allowsRotation = FALSE;
//create a joint to keep the penguin fixed to the scoop until the catapult is released
_penguinCatapultJoint =
[CCPhysicsJoint connectedPivoJointWithBodyA:_currentPenguin.physicsBody
bodyB:_catapultArm.physicsBody
anchorA:_currentPenguin.anchorPointInPoints
];
}
}
-(void)touchMoved:(UITouch *)touch withEvent:(UIEvent *)event{
CCLOG(#"MOVING!!!!!!!!!!");
//whenever touches move,update the position of the mousejointNode to touch position
CGPoint touchLocation = [touch locationInNode:_contentNode];
_mouseJointNode.position = touchLocation;
}
-(void)touchEnded:(UITouch *)touch withEvent:(UIEvent *)event{
//when touches end,meaning the user releases their finger,release the catapult
[self releaseCatapult];
}
-(void)touchCancelled:(UITouch *)touch withEvent:(UIEvent *)event{
[self releaseCatapult];
}
//destroy our joint and let the catapult snap when a touch ends
-(void)releaseCatapult{
CCLOG(#"Release");
if(_mouseJoint != nil)
{
//releases the joint and lets the catapult snap back
[_mouseJoint invalidate];
_mouseJoint = nil;
//release the joint and lets the penguin fly
[_penguinCatapultJoint invalidate];
_penguinCatapultJoint = nil;
//after snapping rotation is fine
_currentPenguin.physicsBody.allowsRotation = TRUE;
//follow the flying penguin
CCActionFollow *follow =
}
}
-(void)retry
{
[[CCDirector sharedDirector]replaceScene:[CCBReader loadAsScene:#"Gameplay"]];
}
-(void)ccPhysicsCollisionPostSolve:(CCPhysicsCollisionPair *)pair seal:(CCNode *)nodeA
wildcard:(CCNode *)nodeB
{
CCLOG(#"Something collided with a seal!");
}
#end

Answer 1

Most likely you did not set a collision type for the Sealclass.
Double check that you have:
Set the custom class for the Seal in SpriteBuilder to Seal
Have set the collisionType within the didLoadFromCCB method inside the Seal class to "seal"
That should fix you issue.

Answer 2

Also, in Spritebuilder, make sure the seals already loaded in the level (Level1.ccb) have Collision type set to seal.