Question

我想用我的数据库中的数据填充我的列表视图，但是当我尝试这样做时它只给了我一个例外，即

 "04-27 13:15:51.139: E/AndroidRuntime(2575): Caused by: java.lang.IllegalArgumentException: column '_id' does not exist"

无论我使用什么适配器，但我都得到同样的例外。

这是我的SQLiteOpenHelper：

public class MySQLiteHelper extends SQLiteOpenHelper {

    //      Table Names
    public static final String TABLE_USER_MASTER = "USER_MASTER";
    public static final String TABLE_ORDER_MASTER = "ORDER_MASTER";
    public static final String TABLE_ORDER_DETAILS = "ORDER_DETAILS";

    //      Database Details
    public static String DB_NAME = "ezeefood.db";
    public static String DB_PATH = "/data/data/com.project.menuApp";
    public static final int DATABASE_VERSION = 4;

    //      User Detail Columns
    public static final String KEY_ID = "_id";
    public static final String KEY_NAME = "Name";
    public static final String KEY_ADDRESS = "Address";
    public static final String KEY_PHONE = "PhoneNo";
    public static final String KEY_USERNAME = "userid";
    public static final String KEY_PASSWORD = "password";

    //      Order Master Columns
    public static final String ORDER_ID = "order_id";
    public static final String ORDER_DATE = "date";
    public static final String ORDER_TIME = "time";

    //      Order Detail Columns
    public static final String ORDER_DETAIL_ID = "order_detail_id";
    public static final String ORDER_ITEM_NAME = "item_name";
    public static final String ORDER_ITEM_RATE = "item_rate";
    public static final String ORDER_ITEM_QTY = "item_qty";
    public static final String ORDER_ID_FINAL = "order_Id";

     private SQLiteDatabase sqLiteDatabase;

    private static final String SCRIPT_CREATE_TABLE_USER_MASTER = "CREATE  TABLE "
            + TABLE_USER_MASTER + "(" + KEY_ID
            + "  INTEGER PRIMARY KEY  AUTOINCREMENT," + KEY_USERNAME + " VARCHAR UNIQUE, "
            + KEY_PASSWORD + " VARCHAR," + KEY_NAME + " VARCHAR,"
            + KEY_ADDRESS + " VARCHAR," + KEY_PHONE + " VARCHAR);";

    private static final String SCRIPT_CREATE_TABLE_ORDER_MASTER = "CREATE  TABLE "
            + TABLE_ORDER_MASTER + "(" + ORDER_ID
            + "  INTEGER PRIMARY KEY  AUTOINCREMENT," + KEY_USERNAME + " VARCHAR, "
            + ORDER_DATE + " VARCHAR," + ORDER_TIME +" VARCHAR);";

    private static final String SCRIPT_CREATE_TABLE_ORDER_DETAILS = "CREATE  TABLE "
            + TABLE_ORDER_DETAILS + "(" + ORDER_DETAIL_ID
            + "  INTEGER PRIMARY KEY  AUTOINCREMENT," + ORDER_ID_FINAL + " INTEGER, "
            + ORDER_ITEM_NAME + " VARCHAR," + ORDER_ITEM_RATE + " FLOAT,"
            + ORDER_ITEM_QTY + " INTEGER DEFAULT 1);";

    public MySQLiteHelper(Context context) {
        super(context, DB_NAME, null, DATABASE_VERSION);
    }

    @Override
    public void onCreate(SQLiteDatabase database) {
        database.execSQL(SCRIPT_CREATE_TABLE_USER_MASTER);
        database.execSQL(SCRIPT_CREATE_TABLE_ORDER_MASTER);
        database.execSQL(SCRIPT_CREATE_TABLE_ORDER_DETAILS);
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

        Log.w(MySQLiteHelper.class.getName(),
                "Upgrading database from version " + oldVersion + " to "
                        + newVersion + ", which will destroy all old data");
        db.execSQL("DROP TABLE IF EXISTS " + TABLE_USER_MASTER);
        db.execSQL("DROP TABLE IF EXISTS " + TABLE_ORDER_MASTER);
        db.execSQL("DROP TABLE IF EXISTS " + TABLE_ORDER_DETAILS);
        onCreate(db);
    }
}

这就是我试图通过简单的游标适配器填充我的列表视图。

public class FinalOrder extends ListActivity {

    Cursor cursor;
    long orderId;
    private SQLiteDatabase mDatabase;
    private MySQLiteHelper mDbhelper;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.orderdetails);
        Bundle c = getIntent().getExtras();
        orderId = c.getLong("orderID");
        mDbhelper = new MySQLiteHelper(this);
        mDatabase = mDbhelper.getReadableDatabase();    
        cursor = mDatabase.query(MySQLiteHelper.TABLE_ORDER_DETAILS, new String [] {MySQLiteHelper.ORDER_ITEM_NAME,
                MySQLiteHelper.ORDER_ITEM_QTY,MySQLiteHelper.ORDER_ITEM_RATE}, "order_Id = ?",
                new String[]{String.valueOf(orderId)}, null, null, null);
        startManagingCursor(cursor);

        String[] from = new String[] {MySQLiteHelper.ORDER_ITEM_NAME,MySQLiteHelper.ORDER_ITEM_QTY,MySQLiteHelper.ORDER_ITEM_RATE};
        int[] to = new int[] {R.id.tv_listItemName,R.id.tv_listItemQTY,R.id.tv_listItemPrice};

        ListAdapter adapter = new SimpleCursorAdapter(this,R.layout.orderlist_row,cursor,from,to);

        setListAdapter(adapter);
    }
}

我不知道为什么它会给出这样的异常，我在访问的表中没有名称为“_id”的列。请帮忙。谢谢！

Answer 1

您正在访问TABLE_ORDER_DETAILS列，其中ORDER_DETAIL_ID列为"order_detail_id"，而不是"_id"。如果您更改它，它应该有效，因为SimpleCursorAdapter期望光标中的列名为_id。

您还必须在查询中包含id列。不重命名表中列的快速修复是在查询中重命名它：

    cursor = mDatabase.query(MySQLiteHelper.TABLE_ORDER_DETAILS,
            new String [] { MySQLiteHelper.ORDER_DETAIL_ID + " AS _id",
            MySQLiteHelper.ORDER_ITEM_NAME,
            MySQLiteHelper.ORDER_ITEM_QTY,
            MySQLiteHelper.ORDER_ITEM_RATE }, "order_Id = ?",
            new String[]{String.valueOf(orderId)}, null, null, null);

无法通过Simplecursoradapter填充ListView

1 个答案: