Question

I am trying to make a timer for my game that counts down from a number, let’s call it 100. I am following the cocos2d best practices, and therefore I am not using a NSTimer. What I am looking to do is that every second, I want to numbers of this timer to change. I could probably find a way to do it using a spritesheet with all of the numbers from 100-0, but I know there is a way to do it using just the numbers 0-9 and their pictures.

This is the code that I am using, with the corresponding -(void)

    [self schedule: @selector(tick:)];
    [self schedule: @selector(tick2:) interval:1];

All in all, I would like to know how to make it count down from 100, but also to know how to make those ticks decrease the value by 1 every second.

Answer 1

Initialize an integer variable that will keep your countdown value:

int count = 100;

You will want to keep a label (CCLabelBMFont etc) to display this count value. I recommend Glyph Designer (or Hierro if you want something free) to generate the 0 to 9 cocos2D-compatible font bitmaps, which you can then use in your CCLabelBMFont:

CCLabelBMFont* countLabel = [CCLabelBMFont labelWithString:@"0" fntFile:@"myFont.fnt"]; 

Next, schedule a single tick function that will fire every second:

[self schedule: @selector(tick:) interval:1];

This tick function decrements count by 1 each time it is called. Also, add the condition that if count has reached 0, it will unschedule itself:

-void tick:(ccTime) dt
{
    count --; // decrement count by 1 each time this function is called
    if (count == 0)
        [self unschedule: @selector(tick:)];      
}

And finally, in your main update loop (or even in the tick function itself after you decrement your count), you can update and redraw this label with the latest value each time:

[countLabel setString:[NSString stringWithFormat:@"%i", count]];

All the best.