當日期格式yyyymdd

-2

這裏是我的數據庫結構日期如何獲得最後7天：當日期格式yyyymdd

我想獲得3分的結果是2017/9/222017/9/242017/9/25如果今天是2017/9/29。

在我的數據庫處理器類我曾嘗試下面的代碼：

public List<Contact> latestDays() { 
     List<Contact> contactList = new ArrayList<>(); 
     // My database time format is: yyyymdd 
     Calendar mCalendar = new GregorianCalendar(); 
     int mYear = mCalendar.get(Calendar.YEAR); 
     int mMonth = mCalendar.get(Calendar.MONTH)+1; 
     int mDay = mCalendar.get(Calendar.DAY_OF_MONTH); 
     String today = String.valueOf(mYear).concat(String.valueOf(mMonth).concat(String.valueOf(mDay))); 
     System.out.println(today+"today"); 
     SQLiteDatabase db = this.getWritableDatabase(); 

     String selectQuery = "SELECT * FROM " + TABLE_CONTACTS + " WHERE date > (SELECT DATETIME('" + today + "'," + "'-7" + " day'))"; 
     Cursor cursor = db.rawQuery(selectQuery, null); 
//looping through all rows and adding to list 
     if (cursor.moveToFirst()) { 
      do { 
       Contact contact = new Contact(); 
       contact.setID(Integer.parseInt(cursor.getString(0))); 
       contact.setDate(cursor.getString(1)); 
       contact.setBeforeMorning(cursor.getString(2)); 
       contact.setAfterMorning(cursor.getString(3)); 
       contact.setBeforeNoon(cursor.getString(4)); 
       contact.setAfterNoon(cursor.getString(5)); 
       contact.setBeforeNight(cursor.getString(6)); 
       contact.setAfterNight(cursor.getString(7)); 
       System.out.println("The result is :" + cursor.getString(1)); 
       //Adding contact to list 
       contactList.add(contact); 
      } while (cursor.moveToNext()); 
     } 

     return contactList; 
    }

我把它放在我的MainActivity這樣的：

private DatabaseHandler db; 
contactList = db.latestDays(); 
System.out.println(contactList.size());

我打印結果是這樣的：

我得到了我的所有記錄，但它不是我想要的。

原因可能是我的日期格式，所以我加我排序的所有日期的年月日至raqQuery：

Cursor cursor = db.rawQuery("SELECT * FROM " + TABLE_CONTACTS +" WHERE date > (SELECT DATETIME('" + today + "'," + "'-7" + " day'))" + 
       " ORDER BY\n" + 
       " SUBSTR(Date, 1, 4) DESC,\n" + 
       " CASE WHEN INSTR(SUBSTR(Date, 6), '/') = 2\n" + 
       " THEN '0' || SUBSTR(Date, 6, 1)\n" + 
       " ELSE SUBSTR(Date, 6, 2) END DESC,\n" + 
       " CASE WHEN LENGTH(SUBSTR(SUBSTR(Date, 6), INSTR(SUBSTR(Date, 6), '/') + 1)) = 1\n" + 
       " THEN '0' || SUBSTR(SUBSTR(Date, 6), INSTR(SUBSTR(Date, 6), '/') + 1)\n" + 
       " ELSE SUBSTR(SUBSTR(Date, 6), INSTR(SUBSTR(Date, 6), '/') + 1) END DESC; ",null);

我仍然得到同樣的結果...

所以我試圖找到另一種解決方案，並嘗試這樣，我更改SQL搜索語法：

 Calendar mCalendar = new GregorianCalendar(); 
     int mYear = mCalendar.get(Calendar.YEAR); 
     int mMonth = mCalendar.get(Calendar.MONTH)+1; 
     int mDay = mCalendar.get(Calendar.DAY_OF_MONTH); 
     String today = String.valueOf(mYear).concat(String.valueOf(mMonth).concat(String.valueOf(mDay))); 
     System.out.println(today+"today"); 
     Calendar theEnd = Calendar.getInstance(); 
     Calendar theStart = (Calendar) theEnd.clone(); 

     theStart.add(Calendar.DAY_OF_MONTH, -7); 

     SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-M-dd"); 
     String start = dateFormat.format(theStart.getTime()); 
     String end = dateFormat.format(theEnd.getTime()); 

     // Now you have date boundaries in TEXT format 

     Cursor cursor = db.rawQuery("SELECT * FROM contacts WHERE date BETWEEN "+start+" AND "+end + 
         " ORDER BY\n" + 
         " SUBSTR(Date, 1, 4) DESC,\n" + 
         " CASE WHEN INSTR(SUBSTR(Date, 6), '/') = 2\n" + 
         " THEN '0' || SUBSTR(Date, 6, 1)\n" + 
         " ELSE SUBSTR(Date, 6, 2) END DESC,\n" + 
         " CASE WHEN LENGTH(SUBSTR(SUBSTR(Date, 6), INSTR(SUBSTR(Date, 6), '/') + 1)) = 1\n" + 
         " THEN '0' || SUBSTR(SUBSTR(Date, 6), INSTR(SUBSTR(Date, 6), '/') + 1)\n" + 
         " ELSE SUBSTR(SUBSTR(Date, 6), INSTR(SUBSTR(Date, 6), '/') + 1) END DESC; ", null);

它更糟糕，我沒有得到任何數據。

如果我的數據庫時間格式爲yyyymdd，我如何得到最新的7天？

來源

2017-09-29 徐博俊

你能共享項目/嘲笑在github上項目這個

final LocalDate currentDate= LocalDate.now(); final LocalDate date7Days = date.minusDays(7); //Format and display date final String formattedDate = date7Days.format(DateTimeFormatter.ISO_LOCAL_DATE); System.out.println(formattedDate);

變化？ – deadfish

爲你明智的存儲日期在一些可排序的格式... fx作爲'LONG'（如milis）或格式爲'yyyy/mm/dd'（日期和飛蛾與前導零）......然後顯然**即使排序爲字符串** 2017/10/1'將大於'2017/9/31'（對於您的格式不適用），因爲9> 1 ......這都是因爲**沒有DATETIME類型在sqlite **（在2017-09） – Selvin

@deadfish你是不是要把這個文件上傳到github上？ –

嘗試根據你的約會時間格式

來源

2017-09-29 12:09:47 YoLo

感謝您的回覆，但我無法找到LocalDate，並且在我的最後一次嘗試中嘗試了yyyymmdd。還包括我的第一次和第二次嘗試。 –

當日期格式yyyymdd

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