iPhone Digital Clock

问题:

After the long time I spent getting an analog clock to work, I am trying to make a digital one (sigh). I am trying to do this with 10 PNGs with the numbers 0 - 9. Each digit of the clock would be an image. The only problem with this is retrieving the certain digit from the current time. I've tried converting the time to a string and using the characterAtIndex, but that doesn't seem to work. What would be the best way to get around this?

回答1:

You could use NSDateComponents and NSCalendar:

NSDate * date = [NSDate date];
NSCalendar * calendar = [[NSCalendar alloc]
                         initWithCalendarIdentifier:NSGregorianCalendar];
NSDateComponents * components =
                    [calendar components:(NSHourCalendarUnit | NSMinuteCalendarUnit) fromDate:date];

NSInteger hour = [weekdayComponents hour];
NSInteger minute = [weekdayComponents minute];
NSInteger firstHourDigit = hour/10;
NSInteger secondHourDigit = hour%10;
NSInteger firstMinuteDigit = minute/10;
NSInteger secondMinuteDigit = minute%10;