iOS 计算某个日期一定天数后的新日期 —— HERO博客

计算某个日期一定天数后的新日期，下面贴上代码：

- (void)viewDidLoad {
    [super viewDidLoad];
    
     = [UIColor whiteColor];

    NSString *date = [self computeDateWithDays:10];
    NSLog(@"date=%@", date);
}

//计算天数后的新日期
- (NSString *)computeDateWithDays:(NSInteger)days
{
    NSDateFormatter *dateFormatter = [NSDateFormatter new];
    [dateFormatter setDateFormat:@"yyyy-MM-dd"];
    NSDate *myDate = [dateFormatter dateFromString:@"2014-04-25"];
    NSDate *newDate = [myDate dateByAddingTimeInterval:60 * 60 * 24 * days];
    
    return [dateFormatter stringFromDate:newDate];
}

某个时间与当前时间比较，计算相差的分钟数（秒、小时、天等都适用，改一下类型就好），代码：

    NSInteger minute = [self getMinuteWithTimeStr:@"2018-01-12 18:00"];
    NSLog(@"minute : %ld", minute);

//传入时间字符串，与当前时间比较，返回分钟差值
- (NSInteger)getMinuteWithTimeStr:(NSString *)timeStr
{
    NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSCalendarIdentifierGregorian];
    [gregorian setFirstWeekday:2];
    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
    [dateFormatter setDateFormat:@"yyyy-MM-dd HH:mm"];
    NSDate *fromDate;
    NSDate *toDate;
    [gregorian rangeOfUnit:NSCalendarUnitMinute startDate:&fromDate interval:NULL forDate:[dateFormatter dateFromString:timeStr]];
    [gregorian rangeOfUnit:NSCalendarUnitMinute startDate:&toDate interval:NULL forDate:[NSDate date]];
    NSDateComponents *components = [gregorian components:NSCalendarUnitMinute fromDate:fromDate toDate:toDate options:0];
    
    return ;
}