Question

我将如何解决这个问题，我有COLUMN_ID，COLUMN_NAME和COLUMN_INTE

COLUMN_INTE持有长整数，我希望它显示在List视图中，它目前不会从最高到最低下降

Answer 1

您需要使用ORDER BY子句针对您的表编写查询，该子句使用DESC关键字指示降序。这样的事情应该有效：

string query = "SELECT COLUMN_ID, COLUMN_NAME, COLUMN_INTE FROM MY_TABLE ORDER BY COLUMN_INTE DESC";
Cursor c = db.rawQuery(query, null);

String[] columns = new String[] { "COLUMN_ID", "COLUMN_NAME"};
int[] to = new int[] {android.R.id.text1, android.R.id.text2};

try {
      dataAdapter = new SimpleCursorAdapter(
           this, android.R.layout.simple_list_item_2, c, columns, to, 0
    );
    ListView lv = (ListView) findViewById(R.id.MY_LISTVIEW);
    lv.setAdapter(dataAdapter);
} catch (Exception ex) {
    ex.printStackTrace();
}

Answer 2

您也可以使用比较器进行排序。就像一个例子 -

类MySalaryComp实现Comparator {

@Override
public int compare(Empl e1, Empl e2) {
    if(e1.getSalary() < e2.getSalary()){
        return 1;
    } else {
        return -1;
    }
}

}

Answer 3

您有两种选择：使用为您排序的SQL命令，或者您可以获取整个列表并自行排序。

SQL命令排序：

    // Create an object to store rows from the table
    tableRowObject = new tableRowObject();
    String query = "select * from STATISTICS order by COLUMN_INTE";
    Cursor cursor = db.rawQuery(query, null);
    if(cursor.getCount()<1) // COLUMN_INTE Not Found
    {
        cursor.close();
    }
    else
    {
        while(cursor.moveToNext())
        {
            // Get COLUMN_ID, COLUMN_NAME, COLUMN_INTE
            int columnID = cursor.getInt(cursor.getColumnIndex("COLUMN_ID"));
            String columnName = cursor.getString(cursor.getColumnIndex("COLUMN_NAME"));
            int columnInte = cursor.getInt(cursor.getColumnIndex("COLUMN_INTE"));

            // Add the variables to a new object
            tableRowObject.add(columnID, columnName, columnInte);
        }

        cursor.close();
    }

自己排序：

    // Create an object to store rows from the table
    tableRowObject = new tableRowObject();
    String query = "select * from STATISTICS";
    Cursor cursor = db.rawQuery(query, null);
    if(cursor.getCount()<1) // COLUMN_INTE Not Found
    {
        cursor.close();
    }
    else
    {
        while(cursor.moveToNext())
        {
            // Get COLUMN_ID, COLUMN_NAME, COLUMN_INTE
            int columnID = cursor.getInt(cursor.getColumnIndex("COLUMN_ID"));
            String columnName = cursor.getString(cursor.getColumnIndex("COLUMN_NAME"));
            int columnInte = cursor.getInt(cursor.getColumnIndex("COLUMN_INTE"));

            // Add the variables to a new object
            tableRowObject.add(columnID, columnName, columnInte);
        }

        cursor.close();
    }
    // Sort the object

更新sqlite数据库以从最高值向下排序整数

3 个答案: