//1.时间格式 NSDateFormatter *_dateFormatter = [[NSDateFormatter alloc] init]; [_dateFormatter setDateFormat:@"YYYY年MM月dd天hh小时mm分ss秒"];  //2.获取系统时间 NSString *date = [_dateFormatter stringFromDate:[NSDate date]];  //3.NSDate转化为时间戳 NSTimeInterval a=[date timeIntervalSince1970];  //4.时间戳转化为NSDate NSDate *stampDate = [NSDate dateWithTimeIntervalSince1970:timeInter];  //4.NSDate转化为NSString NSString* dateString = [_dateFormatter stringFromDate:date];  //5.传入时间差,重置格式 //传入时间差,转换格式 - (NSString *)timeWithMessageString:(NSTimeInterval)timeInter {          int month = timeInter / (3600 * 24 * 30);     int day = timeInter / (3600 * 24);     int hour = timeInter / 3600;     int minute = timeInter / 60;          int day_process = day - month * 30;     int hour_process = hour - day *24;     int minute_process = minute - hour *60;     int miao_process = timeInter - minute*60;          NSString *timedate = nil;     if (day == 0) {         timedate = [NSString stringWithFormat:@"%d小时%d分%d秒",hour_process,minute_process,miao_process];         if (hour == 0) {            timedate = [NSString stringWithFormat:@"%d分%d秒",minute_process,miao_process];             if (hour == 0) {                 timedate = [NSString stringWithFormat:@"%d秒",miao_process];             }         }     }else{         timedate = [NSString stringWithFormat:@"%d天%d小时%d分%d秒",day_process,hour_process,minute_process,miao_process];     }               timedate = [NSString stringWithFormat:@"限时优惠: 还剩%@",timedate];     return timedate; }

 

//当前时间的半小时后NSDate *date1 = [NSDate date]; NSDate *date2 = [[NSDate date] dateByAddingTimeInterval: 30*60];    NSDate *date3 = [NSDate dateWithTimeIntervalSinceNow:30*60];