從數據庫內容填充微調器（SQLite）

Question

如何從數據庫（SQLite）填充微調框內容

我有POJO：類別，包含ID和名稱，我已經有表，並具有獲取ArrayList的功能，如下所示：

public List<SetcardCategory> getAllSetcardCategory()
{
    List<SetcardCategory> setcardCategories = new ArrayList<SetcardCategory>();
    String selectQuery = "SELECT  * FROM " + TABLE_SETCARD_CATEGORIES;

    SQLiteDatabase db = this.getReadableDatabase();
    Cursor c = db.rawQuery(selectQuery, null);

    // looping through all rows and adding to list
    if (c.moveToFirst()) {
        do {
            SetcardCategory setcardCategory = new SetcardCategory();
            setcardCategory.setId(c.getInt((c.getColumnIndex("id"))));
            setcardCategory.setName(c.getString(c.getColumnIndex("name")));

            // adding to tags list
            setcardCategories.add(setcardCategory);
        } while (c.moveToNext());
    }
    return setcardCategories;
}

然后在活動上，我這樣稱呼它：

List<SetcardCategory> setcardCategories = db.getAllSetcardCategory();
    ArrayAdapter<SetcardCategory> arrayAdapter = new ArrayAdapter<SetcardCategory>(
            this, android.R.layout.simple_spinner_item, setcardCategories);
    arrayAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    Spinner sItems = (Spinner) findViewById(R.id.setcardCategory);
    sItems.setAdapter(arrayAdapter);

當我運行它時，它會加載這樣的字符串：“ schema.SetcardCategory@22293c98”以及許多與此類似的值。

如何填充微調框，以將名稱字段顯示為標簽，將id字段顯示為我們獲取以保存到DB中的值？

Answer 1

class Pojo{
 private String name;
  @Override
    public String toString() {
        return name;
    }
}

在pojo類中這樣做，因此當它在適配器中使用to字符串方法來加載數據時，它將為該對象返回一個值。

Answer 2

解決方案1覆蓋SetcardCategory類中的toString方法

class SetcardCategory {
...
...
@Override
    public String toString() {
        return this.name;
    }
}

解決方案2如果僅想顯示名稱，則僅從數據庫中選擇名稱

public List<String> getAllSetcardCategory()
    {
        List<String> setcardCategories = new ArrayList<String>();
        String selectQuery = "SELECT  * FROM " + TABLE_SETCARD_CATEGORIES;

        SQLiteDatabase db = this.getReadableDatabase();
        Cursor c = db.rawQuery(selectQuery, null);

        // looping through all rows and adding to list
        if (c.moveToFirst()) {
            do {
                // adding to tags list
                setcardCategories.add(c.getString(c.getColumnIndex("name")));
            } while (c.moveToNext());
        }
        return setcardCategories;
    }

並創建陣列適配器為

List<String> setcardCategories = db.getAllSetcardCategory();
    ArrayAdapter<SetcardCategory> arrayAdapter = new ArrayAdapter<SetcardCategory>(
            this, android.R.layout.simple_spinner_item, setcardCategories);
    arrayAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);