Globally Declare Sprite? « cocos2d for iPhone

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Globally Declare Sprite?

(10 posts) (5 voices)

Started 1 year ago by Taylor Jasko
Latest reply from Taylor Jasko

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Taylor Jasko
Member

Hi Everyone,

Please excuse me, but I am new to Objective C. But I'm not a dumby at it either because I know other programming languages like it.

I'm wondering how would you globally declare a sprite to be able to do certain things to it when the code (like a RunAction) isn't in the file it's declared in. Would I have to do something with the header (.h) file to make the sprite global?

I've heard of a singleton, but I don't know if that's what I want to use or even exactly how to use it for a sprite.

Would any of you be willing to give me some pointers?

Thanks so much! And by the way, I love your framework.

Posted 1 year ago #
Tim
Member

@tjasko1, there are a few threads on this topic so you might want to search for global variables. I recall staring at these for a while sometime ago:

post1

post2

Posted 1 year ago #
David994A
Member
How about putting a pointer to your sprite as an instance variable in your .h file:
```
@interface someobj: NSObject {
     CCSprite *mySprite;
}

- (void) performActionOnMySprite:(id)someAction;

@end
```
As long as you include that .h file in the other file where you want to perform the action you should be ok.

Global variables are generally frowned upon in Objective C
Posted 1 year ago #
slipster216
Moderator
I'm a big fan of C style externs for global singletons:
```
// in .m
extern CCSprite* TheSprite

-(id)init
{
   TheSprite = [CCSprite node];
}
```
Posted 1 year ago #
Taylor Jasko
Member

@Tim: I've looked around, but none of them seem to do the trick. Granted, that I am new to this.

@David994A: That's what I would of thought. If I would just simply declare it in the header file, it should of done the trick. But apparently not.

@slipster216:Hmm, that doesn't seem to work. It seems easy enough, but it just doesn't work...

To help you out, and even myself, here's the code:

In 1.m (yes, I did alter the file names...) under "-(id) init"
CCSprite *one = [CCSprite spriteWithFile:@"01.png"];

one.position = ccp( size.width /2 , size.height /2 ); //size is declared in a previous statement

[self addChild: one];

Then in 2.m I'm detecting the touches in a certain region, and then I would like to do things to the sprite:

- (BOOL) ccTouchesBegan:(NSSet *)touches withEvent:(UIEvent *) event {
UITouch* touch = [touches anyObject];
CGPoint location = [touch locationInView: [touch view]];
CGRect touchregion = CGRectMake(180, 0, 300, 320);

if(CGRectContainsPoint(touchregion, location)) {
//touchregion touched

//this is why I would need the global variable. It says it's not declared, and yes, I did import 1.h.
id myAction = [CCRotateBy actionWithDuration:72 angle:360];
id RepeatAction = [CCRepeatForever actionWithAction: myAction];
[one runAction: RepeatAction];

[self addChild: one];
}
return kEventHandled;
}

I hope that might help. I'm sorry I'm such a noob at this, but I know this awesome community will be able to help a dev out.

Posted 1 year ago #

Taylor Jasko
Member

Repost to format code.

@Tim: I've looked around, but none of them seem to do the trick. Granted, that I am new to this.

@David994A: That's what I would of thought. If I would just simply declare it in the header file, it should of done the trick. But apparently not.

@slipster216:Hmm, that doesn't seem to work. It seems easy enough, but it just doesn't work...

To help you out, and even myself, here's the code:

In 1.m (yes, I did alter the file names...) under "-(id) init"

CCSprite *one = [CCSprite spriteWithFile:@"01.png"];

one.position = ccp( size.width /2 , size.height /2 ); //size is declared in a previous statement

[self addChild: one];

Then in 2.m I'm detecting the touches in a certain region, and then I would like to do things to the sprite:

- (BOOL) ccTouchesBegan:(NSSet *)touches withEvent:(UIEvent *) event {
UITouch* touch = [touches anyObject];
CGPoint location = [touch locationInView: [touch view]];
CGRect touchregion = CGRectMake(180, 0, 300, 320);

if(CGRectContainsPoint(touchregion, location)) {
//touchregion touched

//this is why I would need the global variable. It says it's not declared, and yes, I did import 1.h.
id myAction = [CCRotateBy actionWithDuration:72 angle:360];
id RepeatAction = [CCRepeatForever actionWithAction: myAction];
[one runAction: RepeatAction];

[self addChild: one];
}
return kEventHandled;
}

I hope that might help. I'm sorry I'm such a noob at this, but I know this awesome community will be able to help a dev out.

Posted 1 year ago #

Matt Rix
Member

Yeah I do things the same way as Slipster. It works like a charm.

Posted 1 year ago #
Taylor Jasko
Member

@Matt: Then do you have any idea why it doesn't work for me? Could be something in my code...

Posted 1 year ago #
David994A
Member

@tjasko1 - A few questions/observations:
1. In your 1.m file you create a sprite and add it to "self" - what type of object is "self" referring to - it should be a layer or a sprite sheet? I'm assuming layer here.
2. You are declaring a local pointer to CCSprite in your 1.m init method by using "CCSprite *one = ...". This pointer is a local variable and therefore does not have any scope beyond the method "init" which is why you are getting errors. What you need to do is declare "CCSprite *one;" either in a header file of a class as an instance variable of an object - or - as a global outside of the @implementation in a file but you must also then use the extern keyword on it in any other file. I personally prefer the first way as it is more inline with objective C and not regular K&R C.

Posted 1 year ago #
Taylor Jasko
Member

@David994A:

1) Yes, it's referring to a layer.

2) Sorry, but I do not understand completely. I know that self does make it a local variable, but what exactly am I supposed to do to make it a global? I really do not get, "a header file of a class as an instance variable of an object".

If you might be willing to take my code and show me, that would be really helpful... of course, I didn't show the header files, but they're just not too important b/c I didn't declare anything else than the layer in them.

Posted 1 year ago #

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