CODEWITHSUNDEEP
objective-ccocos2d-iphone
Curnelious
Curnelious

Reputation: 1

get a instance variable from another class?

I know this is a basic questions but it some how does not work.

I have an enemy class which has in its .h an instance variable :

@interface Enemy : CCLayer
{
    CCSprite *enemy1;
    CGSize winSize ;

}

I have another class which is the game class , and which wants to get access to the enemy1. So, this game class is importing the enemy.h ,and can use its functions , BUT i cant get its pointer enemy1, i have tried with no luck :

   Enemy *enemy=[[Enemy alloc]init];
    [enemy enemy1]//error
    enemy.enemy1 //error

Upvotes: 3

Views: 102

Answers (4)

m177312
m177312

Reputation: 1209

You ought to use @property instead of creating ivars.

.h
@property (nonatomic) CCSprite *enemy1;


.m
@synthesize enemy1;

Upvotes: 2

giorashc
giorashc

Reputation: 13713

you need to define a getter for your enemy1 member. Most recommended way is to declare it as a property :

@property (nonatomic, readonly)  CCSprite *enemy1;

And then synthesize it in the implementation file :

@implementation Enemy 

@synthesize enemy1;

The @property syntax declares how your member will be treated (at this case only with read permissions and no writing from the outside of the class)

The @synthesize syntax generates the getter and setter methods for you depending on how the property has been declared (and since the property is readonly only the getter will be generated)

You could create a getter method yourself but synthesizing make this job for you (including correctly retaining and releasing when necessary)

You can find more information here

Upvotes: 1

Kyr Dunenkoff
Kyr Dunenkoff

Reputation: 8090

Since ivars by default are protected (means visible only to child classes), you should first declare them as public:

@interface Enemy : CCLayer
{
@public
    CCSprite *enemy1;
    CGSize winSize ;

}

After that you will be able to access ivars via standart C syntax like this: enemy->enemy1.

But why not use properties?

Upvotes: 2

James Holderness
James Holderness

Reputation: 23001

I would suggest you should add readonly properties to access those instance variables.

@property (nonatomic,assign,readonly) CCSprite *enemy1;
@property (nonatomic,assign,readonly) CGSize winSize;

Upvotes: 4

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