iOS NSDate 时间戳 计算时间间隔，多久之前

时间计算

NSDate

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

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

    NSDate *timeDate = [dateFormatter dateFromString:model.created_at];//model.created_at 时间

    //八小时时区

    NSTimeZone *zone = [NSTimeZone systemTimeZone];

    NSInteger interval = [zone secondsFromGMTForDate:timeDate];

    NSDate *mydate = [timeDate dateByAddingTimeInterval:interval];

    NSDate *nowDate = [[NSDate date]dateByAddingTimeInterval:interval];

    //两个时间间隔

    NSTimeInterval timeInterval = [mydate timeIntervalSinceDate:nowDate];

    timeInterval = -timeInterval;

    long temp = 0;

    //    NSString *time;

    if (timeInterval<60) {

        self.timeLabel.text = [NSString stringWithFormat:@"刚刚"];

    }else if ((temp = timeInterval/60)<60){

        self.timeLabel.text = [NSString stringWithFormat:@"%ld分钟前",temp];

    }else if ((temp = timeInterval/(60*60))<24){

        self.timeLabel.text = [NSString stringWithFormat:@"%ld小时前",temp];

    }else if((temp = timeInterval/(24*60*60))<30){

        self.timeLabel.text = [NSString stringWithFormat:@"%ld天前",temp];

    }else if (((temp = timeInterval/(24*60*60*30)))<12){

        self.timeLabel.text = [NSString stringWithFormat:@"%ld月前",temp];

    }else {

        temp = timeInterval/(24*60*60*30*12);

        self.timeLabel.text = [NSString stringWithFormat:@"%ld年前",temp];

    }