Android Sqlite datetime和strftime都返回错误的日期

Question

我的表结构如下：

protected static final String EXPENSE_TABLE = "Expense";
protected static final String EXPENSE_ID = "_id";
protected static final String EXPENSE_AMOUNT= "Amount";
protected static final String EXPENSE_CATEGORY ="Category";
protected static final String EXPENSE_SUBCATEGORY ="SubCategory";
protected static final String EXPENSE_REASONCATEGORY ="ReasonCategory";
protected static final String EXPENSE_DATE ="Date";
protected static final String EXPENSE_EVENT ="Event";
protected static final String CREATE_EXPENSE_TABLE = "CREATE TABLE "+ EXPENSE_TABLE +"(" +
        ""+ EXPENSE_ID +" INTEGER PRIMARY KEY AUTOINCREMENT," +
        ""+ EXPENSE_AMOUNT +" REAL NOT NULL ," +
        ""+ EXPENSE_CATEGORY +" VARCHAR(50) NOT NULL," +
        ""+ EXPENSE_SUBCATEGORY +" VARCHAR(50)  NULL," +
        ""+ EXPENSE_REASONCATEGORY +" VARCHAR(50) NULL ," +
        ""+ EXPENSE_DATE +" DATE NOT NULL," +
        ""+ EXPENSE_EVENT +" VARCHAR(50)" +
        ");";

我的插入查询：

 String sql = "INSERT INTO "+DbHelper.EXPENSE_TABLE +"" +
            "("+DbHelper.EXPENSE_AMOUNT +","+DbHelper.EXPENSE_CATEGORY +","+DbHelper.EXPENSE_SUBCATEGORY+"," +
            " "+DbHelper.EXPENSE_REASONCATEGORY +","+DbHelper.EXPENSE_DATE+","+DbHelper.EXPENSE_EVENT+") " +
            "values(?,?,?,?,?,?)";
    db.beginTransaction();
    SQLiteStatement stmt = db.compileStatement(sql);
    stmt.bindDouble(1, e.getAmount());
    stmt.bindString(2,e.getCategory());
    stmt.bindString(3,e.getNote());
    stmt.bindString(4, e.getReasonCategory());
    stmt.bindLong(5, e.getDate());
    stmt.bindString(6,e.getEvent());
    e.setId(stmt.executeInsert());
    stmt.clearBindings();
    db.setTransactionSuccessful();
    db.endTransaction();
    return e.getId();

当我插入到此表时，我会在其中插入long值。下面你可以找到我的插入查询。如您所见，我为日期绑定了long。当我创建表时，字段被创建为date，但我将其插入为long，正如我在网上发现的那样。但是来自sqlite的结果（当我使用sqlite函数时）要么是模糊的，要么是null，比如24-11--471 11:59:59或"01-01-1970"等。当我用SimpleDateFormat转换long字段时，它看起来很好。结果为真因此，由于sqlite错误地解释了long，我无法编写复杂的查询

Answer 1

  strftime('%Y-%m', milliseconds / 1000, 'unixepoch') did the trick

拆分bby/1000并添加"unixepoch"修复了它。我想要的是长期的转换，实际上是

Answer 2

数据库存储可能会变得有点混乱。在我看来，将数据存储为字符串，然后将其转换回long或int（无论您想要什么类型）

或

使用此方法从android系统中获取日期。然后将其存储在数据库中

@SuppressLint("SimpleDateFormat")
private static String getTime() {
    //for date only
    String pattern = "yyyy-MM-dd";
    //or the one below for time and date
    String pattern2 = "yyyy-MM-dd HH:mm:ss ";
    SimpleDateFormat formatter = new SimpleDateFormat(pattern);
    String key = formatter.format(new Date());
    return key;
}