Listening to change to current week? - macos

Question

I'm testing a few things for my self in OS X, and I would like to know what the best way to do this would be.
I have a method, that returns the current week number.
-(NSInteger) getWeekNumber {
NSDate *date = [NSDate date];
NSCalendar *calendar = [NSCalendar currentCalendar];
NSDateComponents *components = [calendar components:NSWeekCalendarUnit fromDate:date];
return [components week];
}
Since this will only happen once a week it seems stupid to have a thread that will refresh my label once every second or so, but I want the label value to change at the exact second the week number change.
I also want to update a label with the current time, that will actually be once a second, or once a minute depending on settings. Should that just be a thread that runs once a second?

Answer 1

There is no need to use threads for simple tasks like these.
NSTimer is the way to go, do something like this for the weekly updates:
// Exact moment the new week starts
NSDate *date =
// Imagine the new week starts in 5 seconds
NSDate *date = [NSDate dateWithTimeIntervalSinceNow:5];
NSTimer *timer = [[NSTimer alloc]
initWithFireDate: date
interval: 60*60*24*7 // Equals one week
target: self
selector: #selector(updateWeekLabel:)
userInfo: nil
repeats: NO
];
[[NSRunLoop currentRunLoop] addTimer:timer forMode:NSDefaultRunLoopMode];
The following function will be triggered when the new week starts:
-(void)updateWeekLabel:(NSTimer*)theTimer
{
// Get current week and update the label.
// Wait for next week or invalidate the timer like this:
[theTimer invalidate];
}
Use something like this for the clock:
NSTimer *timer = [NSTimer
scheduledTimerWithTimeInterval: 1
target: self
selector: #selector(updateTimeLabel:)
userInfo: nil
repeats: YES
];
[[NSRunLoop currentRunLoop] addTimer:timer forMode:NSDefaultRunLoopMode];
Which triggers this function every second:
-(void)updateTimeLabel:(NSTimer*)theTimer
{
// Get current time and update the label.
}