5
美好的一天。我有一個應用程序使用包含五個數據庫表的數據庫，我想要做的是能夠將這些表中的兩個導出爲CSV文件併發送給他們。在進行初步研究後，我看到OpenCSV Library是將SQLite表導出爲CSV的流行選擇。然而，經過進一步的研究，我發現通過給writeAll(ResultSet rSet, Boolean includeHeaders)函數提供一個ResultSet對象可以實現導出，但是沒有明確顯示如何獲得ResultSet。我試圖尋找關於如何在DatabaseHelper類中使用ResultSet的指南，但我空了。Android - 從SQLite數據庫獲取ResultSet，然後用於OpenCSV
任何人都可以教我如何在我的DatabaseHelper類中實現一個函數，它將返回查詢結果的ResultSet？這裏是我DatabaseHelper類：
public class OrderListDBAdapter {
private DatabaseHelper mDBHelper;
private SQLiteDatabase mDB;
private final Context context;
private static class DatabaseHelper extends SQLiteOpenHelper {
DatabaseHelper(Context context) {
super(context, "itemList.db", null, 1);
}
@Override
public void onCreate(SQLiteDatabase db) {
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
}
}
public OrderListDBAdapter(Context context){
this.context = context;
}
public OrderListDBAdapter open() throws SQLException{
this.mDBHelper = new DatabaseHelper(this.context);
//this.mDB = this.mDBHelper.getWritableDatabase(DBAdapter.key);
this.mDB = this.mDBHelper.getWritableDatabase();
return this;
}
public void close(){
this.mDBHelper.close();
}
//TODO - crud queries
public long insertOrder(OrderListClass order){
Log.d("Angelo", "Hi, insert Order entered");
ContentValues values = new ContentValues();
values.put("orderDate", order.getOrderDate());
values.put("customer", order.getCustomer());
values.put("agent", order.getAgent());
values.put("itemName", order.getItemName());
values.put("price", order.getPrice());
values.put("discount", order.getDiscount());
values.put("quantity", order.getQuantity());
values.put("requestedDiscount", order.getRequestedDiscount());
return this.mDB.insert("OrderList", null, values);
}
public boolean deleteOrder(String productname) {
Log.d("Angelo", "Hi, delete Order entered");
return mDB.delete("OrderList", "itemName =" + productname, null) > 0;
}
public int updateOrder(OrderListClass order) {
Log.d("Angelo", "Hi, update Order entered");
ContentValues values = new ContentValues();
values.put("orderDate", order.getOrderDate());
values.put("customer", order.getCustomer());
values.put("agent", order.getAgent());
values.put("itemName", order.getItemName());
values.put("price", order.getPrice());
values.put("discount", order.getDiscount());
values.put("quantity", order.getQuantity());
values.put("requestedDiscount", order.getRequestedDiscount());
// updating row
return mDB.update("OrderList", values, "itemName" + " = ?", new String[] { order.getItemName() });
}
public ArrayList<OrderSummaryListViewItem> getAllOrders(String date, String customerName){
ArrayList<OrderSummaryListViewItem> orders = new ArrayList<OrderSummaryListViewItem>();
String query = "SELECT itemName, price, discount, quantity, requestedDiscount FROM OrderList WHERE orderDate = '"
+ date + "' AND customer = '" + customerName + "'";
Cursor cursor = mDB.rawQuery(query, null);
if (cursor.moveToFirst()) {
do {
String quantity = cursor.getString(cursor.getColumnIndex("quantity"));
String itemName = cursor.getString(cursor.getColumnIndex("itemName"));
String discount = cursor.getString(cursor.getColumnIndex("discount"));
String price = cursor.getString(cursor.getColumnIndex("price"));
String discRequest = cursor.getString(cursor.getColumnIndex("requestedDiscount"));
OrderSummaryListViewItem entry = new OrderSummaryListViewItem(quantity, itemName, discount, price, discRequest);
orders.add(entry);
} while (cursor.moveToNext());
}
cursor.close();
return orders;
}
}
我有一種感覺，它類似於執行查詢，但是，而不是得到一個遊標，我應該得到一個結果和結果集返回到我的活動。
我也可以選擇將sqlite數據庫導出到csv文件。