iOS 与时间相关的处理

• 类似朋友圈发布时间显示（刚刚... 多少分钟多少小时前 昨天）
  - (NSString *)transformDateStrToMinutes:(NSString *)dateStr {

      NSDateFormatter *date=[[NSDateFormatter alloc] init];
      [date setDateFormat:@"yyyy-MM-dd HH:mm:ss"];
      NSDate *d=[date dateFromString:dateStr];
      NSTimeInterval late=[d timeIntervalSince1970]*1;
  
      //当前时间
      NSDate* dat = [NSDate dateWithTimeIntervalSinceNow:0];
      NSTimeInterval now=[dat timeIntervalSince1970]*1;
  
      //单位是秒
      NSTimeInterval cha=now-late;
      NSString *timeString= @"";
      if (cha / 3600 < 1) {
          //小时
          timeString = [NSString stringWithFormat:@"%f", cha/60];
          //        NSLog(@"timeString%@",timeString);
          timeString = [timeString substringToIndex:timeString.length-7];
          int num= [timeString intValue];
          if (num <= 1) {
               timeString = [NSString stringWithFormat:@"刚刚..."];
              //                NSLog(@"timeString = %@",timeString);
          }else{
              timeString = [NSString stringWithFormat:@"%@分钟前", timeString];
              //                NSLog(@"timeString = %@",timeString);
          }
       }
        //86400=1天
        if (cha / 3600 > 1 && cha / 86400 < 1){
            timeString = [NSString stringWithFormat:@"%f", cha/3600];
          timeString = [timeString substringToIndex:timeString.length-7];
          timeString=[NSString stringWithFormat:@"%@小时前", timeString];
          //            NSLog(@"timeString = %@",timeString);
        }
        if (cha/86400>1){
            timeString = [NSString stringWithFormat:@"%f", cha/86400];
          timeString = [timeString substringToIndex:timeString.length-7];
          int num=[timeString intValue];
          if (num<2){
              timeString = [NSString stringWithFormat:@"昨天"];
              //                NSLog(@"timeString = %@",timeString);
          }else {
                NSString * secondStr  = [dateStr substringFromIndex:5];
              timeString = [secondStr substringToIndex:11];
          }
        }
      return timeString;
  }
  

• 时间戳转化为时间NSDate
  - (NSString *)timeWithTimeIntervalString:(NSString )timeString
  {
  // 格式化时间
  NSDateFormatter formatter =[[NSDateFormatter alloc] init];
  formatter.timeZone = [NSTimeZone timeZoneWithName:@"beijing"];
  [formatter setDateStyle:NSDateFormatterMediumStyle];
  [formatter setTimeStyle:NSDateFormatterShortStyle];
  [formatter setDateFormat:@"yyyy-MM-dd HH:mm:ss"];

      // 毫秒值转化为秒
      NSDate* date = [NSDate dateWithTimeIntervalSince1970:[timeString doubleValue]/ 1000.0];
      NSString* dateString = [formatter stringFromDate:date];
      return dateString;
  }
  

• 将时间戳转化成具体时间字符串(具体到秒)
  - (NSString *)transformTimeStampToTimeStr:(NSString *)timeStamp {
  NSString *time = [NSString stringWithFormat:@"%f",[timeStamp doubleValue]];

      NSInteger num = [time integerValue]/1000;
  
      NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
  
      [formatter setDateStyle:NSDateFormatterMediumStyle];
  
      [formatter setTimeStyle:NSDateFormatterShortStyle];
  
      [formatter setDateFormat:@"YYYY-MM-dd HH:mm:ss"];
  
      NSDate * confromTimesp = [NSDate dateWithTimeIntervalSince1970:num];
      NSString * confromTimespStr = [formatter stringFromDate:confromTimesp];
      return confromTimespStr;
  }