这个算法很好的解决了闰年的比较,同时也解决了每个月的月初和上个月的末尾不好判断的问题,简单的来说就是用日历和时间差比对
/**
* 是否为今天
*/
- (BOOL)isToday
{
NSCalendar *calendar = [NSCalendar currentCalendar];
int unit = NSCalendarUnitDay | NSCalendarUnitMonth | NSCalendarUnitYear;
// 1.获得当前时间的年月日
NSDateComponents *nowCmps = [calendar components:unit fromDate:[NSDate date]];
// 2.获得self的年月日
NSDateComponents *selfCmps = [calendar components:unit fromDate:self];
return
(selfCmps.year == nowCmps.year) &&
(selfCmps.month == nowCmps.month) &&
(selfCmps.day == nowCmps.day);
}
/**
* 是否为昨天
*/
- (BOOL)isYesterday
{
// 2014-05-01
NSDate *nowDate = [[NSDate date] dateWithYMD];
// 2014-04-30
NSDate *selfDate = [self dateWithYMD];
// 获得nowDate和selfDate的差距
NSCalendar *calendar = [NSCalendar currentCalendar];
NSDateComponents *cmps = [calendar components:NSCalendarUnitDay fromDate:selfDate toDate:nowDate options:0];
return cmps.day == 1;
}
- (NSDate *)dateWithYMD
{
NSDateFormatter *fmt = [[NSDateFormatter alloc] init];
fmt.dateFormat = @"yyyy-MM-dd";
NSString *selfStr = [fmt stringFromDate:self];
return [fmt dateFromString:selfStr];
}
/**
* 是否为今年
*/
- (BOOL)isThisYear
{
NSCalendar *calendar = [NSCalendar currentCalendar];
int unit = NSCalendarUnitYear;
// 1.获得当前时间的年月日
NSDateComponents *nowCmps = [calendar components:unit fromDate:[NSDate date]];
// 2.获得self的年月日
NSDateComponents *selfCmps = [calendar components:unit fromDate:self];
return nowCmps.year == selfCmps.year;
}
- (NSDateComponents *)deltaWithNow
{
NSCalendar *calendar = [NSCalendar currentCalendar];
int unit = NSCalendarUnitHour | NSCalendarUnitMinute | NSCalendarUnitSecond;
return [calendar components:unit fromDate:self toDate:[NSDate date] options:0];
}