android - 从 2 个表 SQLite 数据库填充 ListView

Question

我想从 SQLite 数据库中的 2 个表填充一个 ListView 。 ListView 将包含 3 个 View :一个 ImageView 和 2 个 TextView 。

• 第一个表:imageview 和 textview1
• 第二张表:textview2

我可以成功地从一个表中查询数据并将其显示在 ListView 中，但不知道如何从第二个表中查询，然后将其添加到列表中。

下面的代码显示了一个仅包含来自 my_folders 的数据的 ListView 。我如何更改它，以便 textview1 显示来自表 my_folders 的数据，而 textview2 显示来自 my_expenses 的数据。任何人都可以帮忙吗？

这是我的主程序:

public class mymain extends ListActivity { ListView listContent;

SimpleCursorAdapter cursorAdapter; final DBAdapter mySQLiteAdapter = new DBAdapter(this); Cursor cursor;

/** Called when the activity is first created. */

@Override public void onCreate(Bundle savedInstanceState) {

  super.onCreate(savedInstanceState);

// setContentView(R.layout.list_example);

  listContent = (ListView) findViewById(R.id.custom_list);
  final DBAdapter mySQLiteAdapter = new DBAdapter(this);

  mySQLiteAdapter.open();

  cursor = mySQLiteAdapter.getAllFolders();

  String[] from = new String[] { DBAdapter.KEY_NAME,DBAdapter.KEY_CURRENCY };
  int[] to = new int[] { R.id.name_row, R.id.notes_row };


  cursorAdapter = new SimpleCursorAdapter(this, R.layout.list_row, cursor,
          from, to);

  setListAdapter(cursorAdapter);
  mySQLiteAdapter.close();

} }

这是我的数据库:

import android.database.Cursor;

public class DBAdapter {
    public static final String KEY_ROWID = "_id"; 
    public static final String KEY_NAME = "name";
    public static final String KEY_CURRENCY = "currency";
    public static final String KEY_NOTES = "notes";
    public static final String KEY_EXPENSE_NAME = "expense_name";
    public static final String KEY_EXPENSE_AMOUNT = "expense_amount";
    public static final String KEY_EXPENSE_DATE = "expense_date";
    public static final String KEY_EXPENSE_TIME = "expense_time";
    public static final String KEY_EXPENSE_NOTES = "expense_notes";
    public static final String KEY_EFOLDERID = "e_fid";

    private static final String TAG = "DBAdapter";

    private static final String DATABASE_NAME = "MyDB";
    private static final String DATABASE_TABLE1 = "my_folders";
    private static final String DATABASE_TABLE2 = "my_expenses";
    private static final int DATABASE_VERSION = 1;

    private static final String DATABASE_CREATE_FOLDERS = 
        "create table my_folders (_id integer primary key autoincrement, "
            + "name text not null, currency text not null, notes text);";

    private static final String DATABASE_CREATE_EXPENSES = 
        "create table my_expenses (_id integer primary key autoincrement, "
            + "expense_name text not null, expense_amount real not null, " +
                    "expense_date text not null, expense_time text not null," +
                    "expense_notes text,"
        + "e_fid integer not null," +
                    "FOREIGN KEY ("+ KEY_EFOLDERID+ ") REFERENCES " + DATABASE_TABLE1 +" ("+ >KEY_ROWID + ") ON DELETE CASCADE);";

    // ---retrieves all the contacts---
    public Cursor getAllFolders() {
        return db.query(DATABASE_TABLE1, new String[] { KEY_ROWID, KEY_NAME,
                KEY_CURRENCY, KEY_NOTES}, null, null, null, null, null);
    }

    // ---retrieves all the expenses---
    public Cursor getAllExpenses() {
        return db.query(DATABASE_TABLE2, new String[] { KEY_ROWID, KEY_EXPENSE_NAME,
                KEY_EXPENSE_AMOUNT, KEY_EXPENSE_DATE, KEY_EXPENSE_TIME, KEY_EXPENSE_NOTES, >KEY_EFOLDERID}, null, null, null, null, null);
    }

Answer 1

从 2 个表中获取数据的最佳方法是使用连接查询，例如

SELECT name, expense_name, expense_notes
FROM my_folders, my_expenses
WHERE my_folders._id = my_folders.e_fid

这将返回 1 Cursor 中的所有数据，然后您可以将其放入 View