Diferença em horas entre dois NSDate
Aqui estou tentando calcular as horas entre duas datas. Quando eu executo o aplicativo, ele falha. Você poderia por favor me dizer o erro neste código?
<code>NSString *lastViewedString = @"2012-04-25 06:13:21 +0000"; NSDateFormatter *dateFormatter = [[[NSDateFormatter alloc] init] autorelease]; [dateFormatter setDateFormat: @"yyyy-MM-dd HH:mm:ss zzz"]; NSDate *lastViewed = [[dateFormatter dateFromString:lastViewedString] retain]; NSDate *now = [NSDate date]; NSLog(@"lastViewed: %@", lastViewed); //2012-04-25 06:13:21 +0000 NSLog(@"now: %@", now); //2012-04-25 07:00:30 +0000 NSTimeInterval distanceBetweenDates = [now timeIntervalSinceDate:lastViewed]; double secondsInAnHour = 3600; NSInteger hoursBetweenDates = distanceBetweenDates / secondsInAnHour; NSLog(@"hoursBetweenDates: %@", hoursBetweenDates); </code>