/*******
设置两个时间差为固定值
*******/
NSCalendar *calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSCalendarIdentifierGregorian];
NSDate *currentDate = [NSDate date];
NSDateComponents *comps = [[NSDateComponents alloc] init];
[comps setDay:1];//设置最大时间为：当前时间推后1天
NSDate *maxDate = [calendar dateByAddingComponents:comps toDate:currentDate options:0];
NSDateFormatter *formater = [[NSDateFormatter alloc] init];
formater.dateFormat =@"yyyy-MM-dd HH:mm";
/*******
日期可以进行比较以确定大小或相等，也可以确定两个日期之间的时间间隔。两个日期的间隔时间差可以使用-timeIntervalSinceDate:方法来计算
*******/
NSDate* now = [NSDatedate];
NSDate* anHourAgo = [nowdateByAddingTimeInterval:-60*60];
NSTimeIntervaltimeBetween = [nowtimeIntervalSinceDate:anHourAgo];
NSLog(@"%f",timeBetween);//结果：3600.000000
/*******
日期比较也可以使用-timeIntervalSinceNow方法获取和当前的时间间隔
*********/
NSDate* anHourago = [NSDatedateWithTimeIntervalSinceNow:-60*60];
NSTimeIntervalinterval = [anHouragotimeIntervalSinceNow];
NSLog(@"%f",interval);//结果：-3600.000007
/****
iOS比较日期大小默认会比较到秒
****/
+(int)compareOneDay:(NSDate*)oneDay withAnotherDay:(NSDate*)anotherDay
{
NSDateFormatter*dateFormatter = [[NSDateFormatteralloc]init];
[dateFormattersetDateFormat:@"dd-MM-yyyy"];
NSString*oneDayStr = [dateFormatterstringFromDate:oneDay];
NSString*anotherDayStr = [dateFormatterstringFromDate:anotherDay];
NSDate*dateA = [dateFormatterdateFromString:oneDayStr];
NSDate*dateB = [dateFormatterdateFromString:anotherDayStr];
NSComparisonResultresult = [dateAcompare:dateB];
NSLog(@"date1 : %@, date2 : %@", oneDay, anotherDay);
if(result ==NSOrderedDescending) {
//NSLog(@"Date1 is in the future");
return1;
}
elseif(result ==NSOrderedAscending){
//NSLog(@"Date1 is in the past");
return-1;
}
//NSLog(@"Both dates are the same");
return0;
}
/************
日期格式请传入：2013-08-05 12:12:12；如果修改日期格式，比如：2013-08-05，则将[df setDateFormat:@"yyyy-MM-dd HH:mm:ss"];修改为[df setDateFormat:@"yyyy-MM-dd"];
***********/
+(int)compareDate:(NSString*)date01 withDate:(NSString*)date02{
intci;
NSDateFormatter*df = [[NSDateFormatteralloc]init];
[dfsetDateFormat:@"yyyy-MM-dd HH:mm:ss"];
NSDate*dt1 = [[NSDatealloc]init];
NSDate*dt2 = [[NSDatealloc]init];
dt1 = [dfdateFromString:date01];
dt2 = [dfdateFromString:date02];
NSComparisonResultresult = [dt1compare:dt2];
switch(result)
{
//date02比date01大
caseNSOrderedAscending: ci=1;break;
//date02比date01小
caseNSOrderedDescending: ci=-1;break;
//date02=date01
caseNSOrderedSame: ci=0;break;
default:NSLog(@"erorr dates %@, %@", dt2, dt1);break;
}
returnci;
}
/*********
比较两个日期之间的差值
*******/
+ (instancetype)differencewithDate:(NSString*)dateString withDate:(NSString*)anotherdateString{
{
// _created_at == Thu Oct 16 17:06:25 +0800 2014
// dateFormat == EEE MMM dd HH:mm:ss Z yyyy
// NSString --> NSDate
NSDateFormatter*fmt = [[NSDateFormatteralloc]init];
//如果是真机调试，转换这种欧美时间，需要设置locale
fmt.locale= [[NSLocalealloc]initWithLocaleIdentifier:@"en_US"];
//设置日期格式（声明字符串里面每个数字和单词的含义）
// E:星期几
// M:月份
// d:几号(这个月的第几天)
// H:24小时制的小时
// m:分钟
// s:秒
// y:年
fmt.dateFormat=@"EEE MMM dd HH:mm:ss Z yyyy";
//微博的创建日期
NSDate*createDate = [fmtdateFromString:dateString];
//当前时间
NSDate*now = [NSDatedate];
//日历对象（方便比较两个日期之间的差距）
NSCalendar*calendar = [NSCalendarcurrentCalendar];
// NSCalendarUnit枚举代表想获得哪些差值
NSCalendarUnitunit =NSCalendarUnitYear|NSCalendarUnitMonth|NSCalendarUnitDay|NSCalendarUnitHour|NSCalendarUnitMinute|NSCalendarUnitSecond;
//计算两个日期之间的差值
NSDateComponents*cmps = [calendarcomponents:unitfromDate:createDatetoDate:nowoptions:0];
NSLog(@"%@ %@ %@", createDate, now, cmps);
returncmps;
}
/*********
比较两个日期之间某年或某月或某日或某时等的具体差值
*******/
+ (instancetype)differencewithDate:(NSString*)dateString withDate:(NSString*)anotherdateString{
{
NSDateFormatter* formatter = [[NSDateFormatteralloc]init];
// [formatter setDateFormat: @"yyyy-MM-dd HH:mm:ss"];
[formattersetDateFormat:@"yyyy-MM-dd "];
NSDate*date2 = [formatterdateFromString:dateString];
NSDate*date1 = [formatterdateFromString:anotherdateString];
// NSLog(@"------date1=%@ date2=%@------%@",date1, date2);
NSCalendar*gregorian = [[NSCalendaralloc]initWithCalendarIdentifier:NSGregorianCalendar];
unsignedintunitFlags =NSMonthCalendarUnit;//年、月、日、时、分、秒、周等等都可以
NSDateComponents*comps = [gregoriancomponents:unitFlagsfromDate:date1toDate:date2options:0];
intmonth = [compsmonth];//时间差
NSLog(@"时间差= %d，abs(month)=%d",month,abs(month));
returnmonth;
}
由NSDate转换为NSString:
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:@"yyyy-MM-dd HH:mm:ss"];
NSString *strDate = [dateFormatter stringFromDate:[NSDate date]];
NSLog(@"%@", strDate);
[dateFormatter release];
结果:
2010-08-04 16:01:03
由NSString转换为NSDate:
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:@"yyyy-MM-dd HH:mm:ss"];
NSDate *date = [dateFormatter dateFromString:@"2010-08-04 16:01:03"];
NSLog(@"%@", date);
[dateFormatter release];
结果:
2010-08-04 16:01:03 +0800
日期之间比较可用以下方法
- (BOOL)isEqualToDate:(NSDate *)otherDate;
与otherDate比较，相同返回YES
- (NSDate *)earlierDate:(NSDate *)anotherDate;
与anotherDate比较，返回较早的那个日期
- (NSDate *)laterDate:(NSDate *)anotherDate;
与anotherDate比较，返回较晚的那个日期
- (NSComparisonResult)compare:(NSDate *)other;
该方法用于排序时调用:
.当实例保存的日期值与anotherDate相同时返回NSOrderedSame
.当实例保存的日期值晚于anotherDate时返回NSOrderedDescending
.当实例保存的日期值早于anotherDate时返回NSOrderedAscending
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