How do I change the action of an AtlasSprite

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How do I change the action of an AtlasSprite

(5 posts) (3 voices)

Started 2 years ago by oskob
Latest reply from psionic

Tags:

oskob
Member

Hi!

I'm pretty new to cocos2d (and to Obj-C for that matter) and I'm trying to figure out how to switch actions of an AtlasSprite.

I have an image containing 24 images (for now) for my guy, 23 for a running animation and one for standing. I made a RepeatForever-actin for my running animation, but when i try to switch to the standing animation it crashes. It works just fine if i start with the standing animation, it's just when switching between them it crashes.

I use this code to switch between animations when the screen is touched:

------------------------------------------
.h-file:

AtlasSprite * sprite;
id runAction;
id standAction;

.m-file:

-(void)run
{
[sprite stopAction:standAction];
[sprite runAction:runAction];
}

------------------------------------------

Pretty simple, still I just can't get it to work! Am I doing this compleatly wrong?

Both actions is RepeatForever-actions.

Let me know if you need more code!

Posted 2 years ago #
psionic
Member

just a guess, but make sure that your animation is retained. ie:

runAction = [RepeatForever actionWithAction: myRepeatingAction];

to

runAction = [[RepeatForever actionWithAction: myRepeatingAction] retain];

Chris.

On Fri, Jun 19, 2009 at 5:47 PM, <cocos2d-iphone-discuss@gamesforfood.cl> wrote:
> oskob says:
>
> Hi!
>
> I'm pretty new to cocos2d (and to Obj-C for that matter) and I'm trying to
> figure out how to switch actions of an AtlasSprite.
>
> I have an image containing 24 images (for now) for my guy, 23 for a running
> animation and one for standing. I made a RepeatForever-actin for my running
> animation, but when i try to switch to the standing animation it crashes. It
> works just fine if i start with the standing animation, it's just when
> switching between them it crashes.
>
> I use this code to switch between animations when the screen is touched:
>
> ------------------------------------------
> .h-file:
>
> AtlasSprite * sprite;
> id runAction;
> id standAction;
>
> .m-file:
>
> -(void)run
> {
> [sprite stopAction:standAction];
> [sprite runAction:runAction];
> }
>
> ------------------------------------------
>
> Pretty simple, still I just can't get it to work! Am I doing this compleatly
> wrong?
>
> Both actions is RepeatForever-actions.
>
> Let me know if you need more code!
>
> Read the whole thread.

Posted 2 years ago #
oskob
Member

That did the trick! Thank you! Didn't know you had to manuallt retain stuff like that, I have never had to use retain lika that before :/ Why do I need it now all of a sudden?

Posted 2 years ago #
Codemattic
Moderator

First of all, psionic - nice catch!

oskob,

Dont use id's unless you need to. Give the compiler as much information as you can. Also use properties, and then use dot notation so the compiler can worry about correct retain/release for member variables. Remember in -dealloc to set them to nil.

.h-file:

AtlasSprite * sprite;
Action * runAction;
Action * standAction;

@property(readwrite,retain) Action * runAction;
@property(readwrite,retain) Action * standAction;

.m-file:

@implementation MyClass

@synthesize runAction;
@synthesize standAction;

...

self.runAction = [RepeatForever actionWithAction: myRepeatingAction];

Its great that psionic figured it out from the snippet you posted - even though the error wasnt in your example. If you have a problem with your code, dont post a small snippet, try and post the smallest full example of whats making you crash. Step through your code and find at what line you are crashing - then check the console and post what error you are getting - just saying "it crashes" is pretty vague.

Posted 2 years ago #
psionic
Member

:) Key words were 'new to Obj-C' and that the sequence worked fine if
it started but not after it cleared. You can take a look at what
actually is happening in runAction (namely, the action is being stored
into an NSMutableArray), and understand that NSMutableArray
automatically applies a 'retain' message to objects that are added to
it, and sends a 'release' message to these objects when they are
removed.

I'd say codemattic's advice is very key.. the built in dot notation is
super awesome for release/retain stuff.

One thing to note though on this that is necessary:

say you have Action *runAction with all the property/synthesize done up.

'
-(void) doStuff
{
runAction = [Animate actionWith....]
}

will *not* actually use the retain/release automatically. you need to use

-(void) doStuff
{
self.runAction = [Animate actionWith....]
}

that 'self.' is important.

'

Chris.

On Sat, Jun 20, 2009 at 12:04 PM,
<cocos2d-iphone-discuss@gamesforfood.cl> wrote:
> codemattic says:
>
> First of all, psionic - nice catch!
>
> oskob,
>
> Dont use id's unless you need to. Give the compiler as much information as
> you can. Also use properties, and then use dot notation so the compiler can
> worry about correct retain/release for member variables. Remember in
> -dealloc to set them to nil.
>
> .h-file:
>
> AtlasSprite * sprite;
> Action * runAction;
> Action * standAction;
>
> @property(readwrite,retain) Action * runAction;
> @property(readwrite,retain) Action * standAction;
>
> .m-file:
>
> @implementation MyClass
>
> @synthesize runAction;
> @synthesize standAction;
>
> ...
>
> self.runAction = [RepeatForever actionWithAction: myRepeatingAction];
>
> Its great that psionic figured it out from the snippet you posted - even
> though the error wasnt in your example. If you have a problem with your
> code, dont post a small snippet, try and post the smallest full example of
> whats making you crash. Step through your code and find at what line you are
> crashing - then check the console and post what error you are getting - just
> saying "it crashes" is pretty vague.
>
> Read the whole thread.

Posted 2 years ago #

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