获取当前的时间

- (NSString *)getCurrentTime

{
   NSDateFormatter *formatter = [[NSDateFormatter alloc] init]; [formatter setDateFormat:@"yyyy-MM-dd"]; NSString *dateTime = [formatter stringFromDate:[NSDate date]]; return dateTime;
}

将字符串转成NSDate类型

- (NSDate *)dateFromString:(NSString *)dateString

{
   NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init]; [dateFormatter setDateFormat: @"yyyy-MM-dd"]; NSDate *destDate= [dateFormatter dateFromString:dateString]; return destDate;
}

传入今天的时间，返回明天的时间

NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSCalendarIdentifierGregorian];     
NSDateComponents *components = [gregorian components:NSCalendarUnitWeekday | NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay fromDate:aDate]; 
[components setDay:([components day]+1)];
NSDate *beginningOfWeek = [gregorian dateFromComponents:components];
NSDateFormatter *dateday = [[NSDateFormatter alloc] init]; 
[dateday setDateFormat:@"yyyy-MM-dd"]; 
return [dateday stringFromDate:beginningOfWeek];