NSDate日期计算

时间戳转nsstring

NSTimeInterval interval    =[mStr doubleValue] ;

    NSDate *date  = [NSDate dateWithTimeIntervalSince1970:interval];

    NSDateFormatter *formatter = [[NSDateFormatter alloc] init];

    [formatter setDateFormat:@"yyyy-MM-dd HH:mm:ss"];

    [formatter setTimeZone:[NSTimeZone timeZoneWithName:@"Asia/Beijing"]];

    NSString *dateString      =  [formatter stringFromDate: date];

NSDate转string

NSDate *currentDate = [NSDate date];
//用于格式化NSDate对象
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
//设置格式：zzz表示时区
[dateFormatter setDateFormat:@"yyyy-MM-dd HH:mm:ss zzz"];
//NSDate转NSString
NSString *currentDateString = [dateFormatter stringFromDate:currentDate];

string转NSDate

NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
 [formatter setDateFormat:@"yyyy-MM-dd HH:mm:ss"];
 [formatter setTimeZone:[NSTimeZone timeZoneForSecondsFromGMT:8]];
 NSDate *date0 = [formatter dateFromString:str1];

1、计算两个日期的天数差

+(NSInteger)getDaysFrom:(NSDate *)serverDate To:(NSDate *)endDate
{
    NSCalendar *gregorian = [[NSCalendar alloc]
                             initWithCalendarIdentifier:NSCalendarIdentifierGregorian];
   
    [gregorian setFirstWeekday:2];
  
   //去掉时分秒信息
    NSDate *fromDate;
    NSDate *toDate;
    [gregorian rangeOfUnit:NSCalendarUnitDay startDate:&fromDate interval:NULL forDate:serverDate];
    [gregorian rangeOfUnit:NSCalendarUnitDay startDate:&toDate interval:NULL forDate:endDate];
    NSDateComponents *dayComponents = [gregorian components:NSCalendarUnitDay fromDate:fromDate toDate:toDate options:0];

    return dayComponents.day;
}