前言：
iOS中把時間轉化成“剛剛、幾分鐘前、幾小時前、幾天前、某月某日幾點幾分、.......”格式
這就需要看後臺返回什麼樣的型別了，在專案中碰到的無非就是，格式化後和時間戳了。所以，這次把這兩種我都結合起來，放到這裡，直接拿去用！

一、返回格式化後的時間 2016-10-11 12:33:33

pragma mark 時間格式轉化

注意：資料返回型別為格式化後的時間 eg: "2016-10-11 12:33:33"

• (NSString *) compareCurrentTime:(NSString *)str
  {

  //把字串轉為NSdate
  NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
  [dateFormatter setDateFormat:@"yyyy-MM-dd HH:mm:ss"];
  NSDate *timeDate = [dateFormatter dateFromString:str];

  //得到與當前時間差
  NSTimeInterval timeInterval = [timeDate timeIntervalSinceNow];
  timeInterval = -timeInterval;
  //標準時間和北京時間差8個小時
  // timeInterval = timeInterval - 86060;
  long temp = 0;
  NSString *result;
  if (timeInterval < 60) {
  result = [NSString stringWithFormat:@"剛剛"];
  }
  else if((temp = timeInterval/60) <60){
  result = [NSString stringWithFormat:@"%ld分鐘前",temp];
  }

else if((temp = temp/60) <24){
    result = [NSString stringWithFormat:@"%ld小時前",temp];
}

else if((temp = temp/24) <30){
    result = [NSString stringWithFormat:@"%ld天前",temp];
}

else if((temp = temp/30) <12){
    result = [NSString stringWithFormat:@"%ld月前",temp];
}
else{
    temp = temp/12;
    result = [NSString stringWithFormat:@"%ld年前",temp];
}

return  result;

}

二、返回的是時間戳

pragma mark 時間格式轉化

注意：後臺返回的時間戳包括10位或者有小數點。
eg：“1480064761” 1480064761.000000

• (NSString *)distanceTimeWithBeforeTime:(double)beTime
  {
  NSTimeInterval now = [[NSDate date]timeIntervalSince1970];
  double distanceTime = now - beTime;
  NSString * distanceStr;

  NSDate * beDate = [NSDate dateWithTimeIntervalSince1970:beTime];
  NSDateFormatter * df = [[NSDateFormatter alloc]init];
  [df setDateFormat:@"HH:mm"];
  NSString * timeStr = [df stringFromDate:beDate];

  [df setDateFormat:@"dd"];
  NSString * nowDay = [df stringFromDate:[NSDate date]];
  NSString * lastDay = [df stringFromDate:beDate];

  if (distanceTime < 60) {
  distanceStr = @"剛剛";
  }
  else if (distanceTime <6060) {
  distanceStr = [NSString stringWithFormat:@"%ld分鐘前",(long)distanceTime/60];
  }
  else if(distanceTime <246060 && [nowDay integerValue] == [lastDay integerValue]){
  distanceStr = [NSString stringWithFormat:@"今天 %@",timeStr];
  }
  else if(distanceTime<2460602 && [nowDay integerValue] != [lastDay integerValue]){

    if ([nowDay integerValue] - [lastDay integerValue] ==1 || ([lastDay integerValue] - [nowDay integerValue] > 10 && [nowDay integerValue] == 1)) {
        distanceStr = [NSString stringWithFormat:@"昨天 %@",timeStr];
    }
    else{
        [df setDateFormat:@"MM-dd HH:mm"];
        distanceStr = [df stringFromDate:beDate];
    }
  

  }
  else if(distanceTime <246060*365){
  [df setDateFormat:@"MM-dd HH:mm"];
  distanceStr = [df stringFromDate:beDate];
  }
  else{
  [df setDateFormat:@"yyyy-MM-dd HH:mm"];
  distanceStr = [df stringFromDate:beDate];
  }
  return distanceStr;
  }

三、捎帶福利、獲取當前時間戳方法，返回10位。

pragma mark 獲取當前時間戳

• (NSString *)getCurrentTime{
  NSDate *senddata = [NSDate date];
  NSString *date2 = [NSString stringWithFormat:@"%ld", (long)[senddata timeIntervalSince1970]];
  return date2;
  }