cocos2d for iPhone

A fast, easy to use, free, and community supported 2D game engine

1. 

   andrewBatutin
   Member

   I have a problem. I need to call a method of a scene (HellowWorld for instance) from another class (AnotherClass).
   If i right

   [HellowWorld methodName];

   I've got an error
   Could you please help me&

   Posted 1 year ago #
2. 

   robodude666
   Member

   Does the instance of AnotherClass know about the instance of HelloWorld ? If it doesn't they can't communicate in that fashion. Also, it helps to know the error.

   What sort of thing are you trying to accomplish? You might want to consider using delegation, notification or a singleton depending on your needs.

   Posted 1 year ago #
3. 

   andrewBatutin
   Member

   I have a class PositionCalc, which calculates position of sprite. And i'd like to call an updateScene method in HellowWorld scene from PositionCalc class.

   Posted 1 year ago #
4. 

   andrewBatutin
   Member

   is it going to work if i make HellowWorld method static?

   Posted 1 year ago #
5. 

   Verisutha
   Member

   Create a singlton to share information, and then use notification center to send messages...

   Although I don't understand how positioncalc is getting called unless you are threading it, in which case this should be basic stuff...

   With no code posted we have no real understanding of what you are doing.

   The way you have phrased the question leads me to believe you have no idea how objects work, which will cause some serious havoc later in your development. Maybe you need to read some more about obj-c, or object oriented programming before you begin writing software.

   Posted 1 year ago #
6. 

   steg90
   Member

   I would also recommend a singleton.

   Here is a very simple way of doing one:

   #import "Global.h"
   
   @implementation Global
   static Global *_instance = nil;
   @synthesize _level;
   
   +(Global *)instance
   {
   	if(_instance) return _instance;
   
   	@synchronized([Global class])
   	{
   		if(!_instance)
   		{
   			_instance = [[self alloc] init];
   
   		}
   		return _instance;
   	}
   
   	return nil;
   }
   
   @synthesize _playerFix, _pMainGameLayer;
   
   @end

   @interface Global : NSObject {
   
   	b2Fixture *_playerFix;
   
   	MainGameLayer *_pMainGameLayer;
   
   	int _level;
   
   }
   
   @property (nonatomic) b2Fixture *_playerFix;
   @property (nonatomic,retain) MainGameLayer *_pMainGameLayer;
   @property (readwrite) int _level;
   
   +(Global *)instance;
   
   @end

   This is something I've been using in my game.

   You may also want to look at the observer pattern( a little like delegates ), in fact a good book on design patterns is essential for good software engineering :-)

   Regards,
   Steve

   Posted 1 year ago #
7. 

   Geri
   Member

   Why don't simply message the node itself?

   [[HelloWorld node] methodName];

   Posted 9 months ago #
8. 

   Geri
   Member

   Though this is a far outdated topic, I want to share my experiences.
   The method I wrote above is a complete idiotism.
   So I managed to get a reference to the running scene's node in two steps.

   At HelloWorldScene.m in +(id)scene's implemetation:

   //Tag the brand new layer with a tag
   layer.tag = 42;

   Then in any class we can get a reference to the running scene, and we can get it's layer by tag.

   //Send message to the scene (to the CCLayer subclass actually).
   _node =  [[[CCDirector sharedDirector] runningScene] getChildByTag:42];
   [(HelloWorld*)_node methodName];

   (We can type the node to avoid warning)

   Posted 9 months ago #
9. 

   Benihana
   Member

   The real problem the original poster likely had, is that he was not importing the HelloWorld header, and/or that he was trying to call an instance method on a class.

   Your method works well, assuming you can be certain the child with tag 42 is actually an instance of HelloWorld, and will respond to the message you're sending it. I would say the main layers are significant enough that they warrant tracking with a property (and so HelloWorldScene would respond to mainLayer and return the HelloWorld *mainLayer pointer).

   Posted 9 months ago #
10. 

    Scryb
    Member

    Personally I think the real problem the O.P. had is that he just didn't understand basic objective c.

    Posted 9 months ago #

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