How to put a pointer to an array object

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How to put a pointer to an array object

(25 posts) (4 voices)

Started 5 months ago by gametreesnet
Latest reply from gametreesnet

Tags:

gametreesnet
Member
Hello people.
I have a problem/question on making a pointer to an array object.
This is an example:
```
CCSprite *sprite = [Array objectAtIndex:0];
[self addChild:sprite];
```
So like this, I want to make a separate sprite having data of an array's object.
I made another class for the array and made subclasses for each object in the array.

I put information about sprites in the subclasses (like image and methods), and just declared the object using the above line;
The app crashed on "addChild assert" and I soon realized that the app crash because of this:
[self addChild:sprite]; (Used breakpoint)
I think this is a pointer problem, but I just don't know a way to fix it, so it would be great if you guys tell me some suggestions to fix the problem.
It would also be great if you guys can just give me a link or something to remind me the properties of array (maybe I'm forgetting something).
If this question does not make any sense, feel free to ask me.
Thank you.
Posted 5 months ago #
hm50
Member

Are you sure your array is initialized and has sprites in it? If so try CCSprite *sprite = (CCSprite*)[Array objectAtIndex:0];

Posted 5 months ago #
gametreesnet
Member

What do you mean by initializing it?
I made a class for the array and just put:
Array *array in the main class' header file.
Am I missing something?
Thanks.
And thank you for telling me the bracket thing. I didn't quite understand how that works.

Posted 5 months ago #
gametreesnet
Member

I really need some help.
Thanks.

Posted 5 months ago #
hm50
Member
You put Array *array in your header and didn't get an error? You should use NSArray *array or CCArray *array. After that you need to initialize 'array' and you should then add objects to 'array' before trying to extract objects out of it.

To initialize, perhaps in your init method:
```
array = [CCArray alloc] init];

//create an object:
CCSprite *mySprite = [CCSprite spriteWithFile@"sprite.png"];

//then add it to 'array':
[array addObject:mySprite];

//To extract an object from array:
CCSprite *sprite = (CCSprite*)[array objectAtIndex:0];
```
That should get you started.

Also check out this video (actually his whole series is pretty good and comedic) http://youtu.be/9y2Ci0ynMR8
Posted 5 months ago #
gametreesnet
Member

-(void) addChild: (CCNode*) child
{
NSAssert( child != nil, @"Argument must be non-nil");
[self addChild:child z:child.zOrder tag:child.tag];
}

This is the error that keep comes out.
I read your comment and thought about making an array that is not a separate class.
Then, I remembered that there will be so many objects (sub classes) and that means I have to put a lot of stuff in the header file and init method.
I know that your way of fixing this will definitely work, but if I have a lot of subclasses, I need to add another array class.
Therefore, it would be nice if I can find a way to put this to work.
If this is impossible, I will use your way, but I think there will be a way.
Thank you.

Posted 5 months ago #
hm50
Member

I need to know more about what you are trying to accomplish. From what I have gathered, you have several subclasses (of CCSprite??) and you want them added to an array that you can use in your main game class? I don't understand why you subclassed NSArray. Did you need to change the way NSArray's work?

Posted 5 months ago #
gametreesnet
Member
Well, I've got pretty big amounts of objects to be added.
Then, each object would have different properties so I need to make class for each one of them.
If I make an array in my main class, I would need to import a long list of those objects in man header class like this:
```
#import "object1.h"
#import "object2.h"
#import "object3.h"
#import "object4.h"
#import "object5.h" ...
```
Therefore, I want to make a class that has all the importing things, so I don't need to import objects in the main class.
Also, that means I don't need to put "[array addobject]" like ten times in my init method. That would make the code too messy.
Well, that is the main reason I have.
And furthermore, the class that has the array is inherited from ccArray.
Yes, the objects are inherited from ccSprite
If you have any more questions, please ask me.
Thank you so much.
Posted 5 months ago #
orion1x76
Member

Did you give your sprite a tag when you created it?

e.g.:

CCSprite *mySprite = [CCSprite spriteWithFile@"sprite.png"];
mySprite.tag = 1;

Posted 5 months ago #
gametreesnet
Member

Yes.
I put:
object.tag = 1 in my method.

Posted 5 months ago #

Okay... It's okay to have a class that builds the array, but I don't think you want it to be a subclass of CCArray, rather it may be better to have a class that has a CCArray as a property. Then in that class have a method that returns a CCArray.

-(CCArray) buildArray {

CCArray*array = [[CCArray alloc] init];
 [array addObject:obj1];
 [array addObject:obj2];
 etc

return array;
[array release];
}

Then in your main class:

#import "ArrayBuilder.h"

 //then in the init

CCArray*array = [ArrayBuilder buildArray];

//you should now be able to access the sprites within 'array' by using the <code>[array objectAtIndex:x]</code> method.

(Note that I am not at a mac, so there could be typos here)

Posted 5 months ago #

gametreesnet
Member

So does that mean I shouldn't make my array class inherit from anything?
So like this:

@interface Arrays {
}
?

Posted 5 months ago #
hm50
Member

I don't think it needs to.

Posted 5 months ago #
gametreesnet
Member

I imported the class in the header file and wrote like:
CCArray*array = [ArrayBuilder buildArray];
in my init class but the class does not understand what buildArray is.
I then made a pointer object to ArrayBuilder, but that still didn't work.
What is wrong here?
Thank you.

Posted 5 months ago #
hm50
Member

I need to see ArrayBuilder class.

Posted 5 months ago #
hm50
Member

Have you initialized an instance of the ArrayBuilder class?

Posted 5 months ago #

gametreesnet
Member

Header file:

#import <Foundation/Foundation.h>
#import "cocos2d.h"
#import "Object.h"
#import "Object2.h"
@interface ArrayBuilder {
    Object *object;
    Object2 *object2;
}

@end

Method file:

#import "ArrayBuilder.h"

@implementation ArrayBuilder

-(CCArray*)buildArray{
    CCArray *array = [[CCArray alloc]init];
    [array addObject:object];
    [array addObject:object2];
    return array;
    [array release];
}

-(id)init
{
    self = [super init];
    if (self) {
        [self buildArray];
    }
        return self;
}

@end

I'm not sure if I need the init method, but when I didn't have the method, there was an error, so I just put it to make sure.
Thank you.

Posted 5 months ago #

gametreesnet
Member

Yes.
I put ArrayBuilder *enem;
in my header file of main class.

Posted 5 months ago #
hm50
Member
Make a CCArray*newArray property.

Change init to:
```
-(id)init
{
    self = [super init];
    if (self) {
         newArray = [self buildArray];
    }
        return self;
}
```
In main file make sure to initialize an instance of ArrayBuilder. ArrayBuilder*AB = [[ArrayBuilder alloc] init]; Then you can set array = AB.newArray;.

Again I am doing this off the top of my head, not at xcode.
Posted 5 months ago #
gametreesnet
Member
I really don't know what is wrong here.
I put this:
```
Enemies *enem = [[Enemies alloc]init];
 enemies = enem.newArray;
```
in my init method and there is a warning that Enemies does not know what alloc is.
Then, in my Enemies class, there is an error saying that the class is not a root class so there cannot be super init, so I deleted it.
Finally, I put this:
```
enemy = (CCSprite*)[enemies objectAtIndex:0];
```
in my init file and there is the same error I had:
```
-(void) addChild: (CCNode*) child
{
NSAssert( child != nil, @"Argument must be non-nil");
[self addChild:child z:child.zOrder tag:child.tag];
}
```
I put self add child and even made an initialization of every array that I'm using, but there is the same error.
What am I doing wrong?
Thanks.
Posted 5 months ago #
gametreesnet
Member
Can anyone help me?
Also, I made array property by this:
```
@property (assign) CCArray *newArray;
```
Thank you.
Posted 5 months ago #
FBryant
Member

If you want instant help then show your Enemies class. BUT tbh I'd read up on objective C and try some cocos2d tutorials, else you will keep struggling.

Posted 5 months ago #
gametreesnet
Member

Well I've read quite a bit of books and tutorials and I really don't know what is wrong with this line:
enemy = [enemies objectAtIndex:0];
I followed the rules I know in computer language, so I don't know what I did wrong...
Is it wrong to make a pointer to an object in arrays?

Posted 5 months ago #
gametreesnet
Member

I already showed my enemies class (ArrayBuilder).

Posted 5 months ago #
gametreesnet
Member

Guys I fixed the problem!
Thanks for all the help.

Posted 5 months ago #

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