iOS开发－显示发送时间（几分钟前，几小时前，几天前）

• (NSString *) compareCurrentTime:(NSString *)str
  {
  //把字符串转为NSdate
  NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
  [dateFormatter setDateFormat:@"yyyy-MM-dd HH:mm:ss"];
  NSDate *timeDate = [dateFormatter dateFromString:str];
  NSDate *currentDate = [NSDate date];
  NSTimeInterval timeInterval = [currentDate timeIntervalSinceDate:timeDate];
  long temp = 0;
  NSString *result;
  if (timeInterval/60 < 1)
  {
  result = [NSString stringWithFormat:@"刚刚"];
  }
  else if((temp = timeInterval/60) <60){
  result = [NSString stringWithFormat:@"%ld分钟前",temp];
  }
  else if((temp = temp/60) <24){
  result = [NSString stringWithFormat:@"%ld小时前",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;
  }