Question

I have an NSMutableArray (named coins) that isn’t following a randomPoint method. When I go to iOS Simulator, the coins don’t show up (as in there are no images) and they stay in the center of the screen instead of a randomly assigned point. This is what should make a new coin:

if ([coins count] == 0){

    CGSize windowSize = [CCDirector sharedDirector].winSize;
    CGPoint randomPointOnScreen = ccp((float)(arc4random() % 100) / 100 * windowSize.width, (float)(arc4random() % 100) / 100 * windowSize.height);

   randomCoinType = arc4random() % kNumberOfCoinTypes + 1; // I have this because my files are named like "coin.1.png" and such

kNumberOfCoinTypes is defined as 10 to give me a number 1-10.
This is the corresponding void that should make the coins:

-(void)createCoinsAt:(CGPoint)position withCointype:(int)type{

NSString *imageFile;

switch (type) {


    case 1:

        imageFile = @"coin.1.png";
        break;

    case 2:
        imageFile = @"coin.2.png";
        break;

    case 9:
    case 3:
        imageFile = @"coin.3.png";
        break;

    case 7:
    case 8:
    default:
    case 4:
        imageFile = @"coin.4.png";
        break;

    case 5:
        imageFile = @"coin.5.png";
        break;

    case 6:
        imageFile = @"coin.6.png";
        break;

      }

Coins *c = [Coins spriteWithFile:imageFile];
//Coins *c = [Coins spriteWithFile:[NSString stringWithFormat:@"coin.%d.png", arc4random() % 5 + 1 ]];

c.type = type;
c.position = position;
c.velocity = ccp(0,0);
[coins addObject:c];
[self addChild:c z:2];

}

I have multiple cases following one command because I don’t know how to make one number appear more often than another.

Answer 1

Everything is fine with the code you’ve shown. Your problems are probably in your Coin class.

Things to check in your Coin class:

• Does setting velocity to {0,0} inadvertently change position?
• What CCSprite methods have you overridden? Make sure to call the super of those methods.

Other things to try:

• Can you make a coin.1.png visibly appear at a random point using only the CCSprite class? If not…
  • Make sure the physical coin.1.png file is correctly added to your project.
  • Check the parent objects: are they flagged as invisible? are they added to the scene?

---

UPDATE: Avoiding subclassing CCSprite

@interface Coin : NSObject 

@property (nonatomic, retain) CCSprite *sprite;
@property (nonatomic, assign) CGPoint velocity; 
@property (nonatomic, assign) int type;
@end

—

-(void)createCoinAt:(CGPoint)position withCointype:(int)type{

    NSString *imageFile;
    ...
    //imageFile switch statement here
    ...
    Coin *c = [[Coin alloc] init];

    c.sprite = [CCSprite spriteWithFile:imageFile];
    c.sprite.position = position;
    c.type = type;
    c.velocity = ccp(0,0);
    [coins addObject:c];
    [parentNode addChild:c.sprite z:2]; //make sure to add to correct parent CCNode
}

—
Once a Coin is given a velocity:

//duration assumes velocity is pixels-per-second
CCAction *moveSprite = [CCRepeatForever actionWithAction:[CCMoveBy actionWithDuration:1.0 position:c.velocity]];
[c.sprite runAction:moveSprite]; 

Once a Coin disappears/dies/whatever:

[c.sprite stopAllActions];
[c.sprite removeFromParentAndCleanup:YES];
c.sprite = nil;
[coins removeObject:c];