字符串转化为日期：
NSString *strDate = @"2015-03-20 12:45:54";
NSDateFormatter *frm = [[NSDateFormatter alloc] init];
frm.dateFormat = @"yyyy-MM-dd HH:mm:ss";
NSDate *date = [frm dateFromString:strDate];
国际时间转化：
NSString *str = @"Tue May 21 17:40:55 +0800 2014";
NSDateFormatter *frm = [[NSDateFormatter alloc] init];
frm.dateFormat = @"EEE MMM dd HH:mm:ss Z yyyy";
frm.locale = [[NSLocale alloc] initWithLocaleIdentifier:@"en_US"];
NSDate *date = [frm dateFromString:str];
将现在时间转化为字符串：
NSDate *date = [[NSDate alloc] init];
NSDateFormatter *frm = [[NSDateFormatter alloc] init];
frm.dateFormat = @"yyyy-MM-dd HH:mm:ss";
NSString *str = [frm stringFromDate:date];
获取日期中的某个时间属性：
NSString *string = @"2014-01-20 09:10:05";
NSDateFormatter *frm = [[NSDateFormatter alloc] init];
frm.dateFormat = @"yyyy-MM-dd HH:mm:ss";
NSDate *date = [frm dateFromString:string];
NSCalendar *cld = [NSCalendar currentCalendar];
NSInteger month = [cld component:NSCalendarUnitMonth fromDate:date];
NSInteger hour = [cld component:NSCalendarUnitHour fromDate:date];
NSInteger day = [cld component:NSCalendarUnitDay fromDate:date];
NSString *string = @"2014-01-20 09:10:05";
NSDateFormatter *frm = [[NSDateFormatter alloc] init];
frm.dateFormat = @"yyyy-MM-dd HH:mm:ss";
NSDate *date = [frm dateFromString:string];
NSCalendar *cld = [NSCalendar currentCalendar];
NSCalendarUnit unit = NSCalendarUnitDay|NSCalendarUnitHour|NSCalendarUnitMinute|NSCalendarUnitSecond;
NSDateComponents *dateCom = [cld components:unit fromDate:date];
和手机现在时间比较：
NSString *string = @"2019-01-20 09:10:05";
NSDateFormatter *frm = [[NSDateFormatter alloc] init];
frm.dateFormat = @"yyyy-MM-dd HH:mm:ss";
NSDate *creatdate = [frm dateFromString:string];
NSDate *nowDate = [NSDate date];
NSComparisonResult result = [nowDate compare:creatdate];
/*
NSOrderedAscending = -1L, 升序
NSOrderedSame,
NSOrderedDescending 降序
*/
if (result == NSOrderedAscending) {
NSLog(@"未来时间");
}else if (result == NSOrderedSame){
NSLog(@"现在时间");
}else if (result == NSOrderedDescending){
NSLog(@"过去时间");
}
距离现在多少秒：
NSString *string = @"2015-11-21 19:38:05";
NSDateFormatter *frm = [[NSDateFormatter alloc] init];
frm.dateFormat = @"yyyy-MM-dd HH:mm:ss";
NSDate *creatdate = [frm dateFromString:string];
NSTimeInterval interval = [creatdate timeIntervalSinceNow];
两个时间比较：
NSDateFormatter *frm = [[NSDateFormatter alloc] init];
frm.dateFormat = @"yyyy-MM-dd HH:mm:ss";
NSString *createdAtString = @"2015-11-01 09:10:05";
NSDate *createdAtDate = [frm dateFromString:createdAtString];
NSString *otherString = @"2015-10-31 08:56:45";
NSDate *otherDate = [frm dateFromString:otherString];
NSCalendar *calendar = nil;
// iOS8.0之后使用
if ([NSCalendar resolveInstanceMethod:@selector(calendarWithIdentifier:)]) {
calendar = [NSCalendar calendarWithIdentifier:NSCalendarIdentifierGregorian ];
}else{
calendar = [NSCalendar currentCalendar];
}
NSCalendarUnit unit = NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay | NSCalendarUnitHour | NSCalendarUnitMinute | NSCalendarUnitSecond;
NSDateComponents *com = [calendar components:unit fromDate:createdAtDate toDate:otherDate options:0];
NSLog(@"%@",com);
判断是否是今天：
NSCalendar *calendar = nil;
if ([NSCalendar respondsToSelector:@selector(calendarWithIdentifier:)]) {
calendar = [NSCalendar calendarWithIdentifier:NSCalendarIdentifierGregorian];
} else {
calendar = [NSCalendar currentCalendar];
}
NSDateFormatter *fmt = [[NSDateFormatter alloc] init];
fmt.dateFormat = @"yyyy-MM-dd HH:mm:ss";
NSLog(@"%zd", [calendar isDateInToday:[fmt dateFromString:@"2015-11-10 01:09:56"]]);
// 是否是昨天
- (BOOL)isDateInYesterday:(NSDate *)date
// 是否是明天
- (BOOL)isDateInTomorrow:(NSDate *)date
// 是否在一个星期之内
- (BOOL)isDateInWeekend:(NSDate *)date
