How to call a method once per second in objective-c

Question

My program has a loop that does calculation and drawing like 60 times a second. I want my movement action be executed only once a second, how do I do that with objective-c methods?

Answer 1

You can use

+ (NSTimer *)scheduledTimerWithTimeInterval:(NSTimeInterval)seconds target:(id)target selector:(SEL)aSelector userInfo:(id)userInfo repeats:(BOOL)repeats

For one second:

NSTimer *yourTastTimer = scheduledTimerWithTimeInterval:1 target:yourTarget selector:@selector(yourMethod) userInfo:nil repeats:YES;

You can check the documentation for NSTimer for details.

Edit

You may also want to check this answer.

Answer 2

If you are using Cocos2D for iphone you MUST NOT use the NSTimer.

Following the documentation, you should use the schedule:interval: method like that:

[self schedule: @selector(tick:) interval:1.0f];

- (void) tick: (ccTime) dt
{
    //...
}

Answer 3

If your using a CCSprite ,they have a schedule method which might do the trick. Basically do what for the main loop. You could also keep a ticker in your main loop and check that this is the ticker%60==0. Then call your movement action.

I read NSTimer is discouraged with cocos2d here.