android读取sqlite数据库的数据并用listview显示的代码

以下是一个简单的示例代码，用于从SQLite数据库中读取数据并在ListView中显示：

1. 创建一个数据库帮助类 DBHelper.java：

public class DBHelper extends SQLiteOpenHelper {

    private static final String DATABASE_NAME = "mydatabase.db";
    private static final int DATABASE_VERSION = 1;
    private static final String TABLE_NAME = "mytable";
    private static final String COLUMN_ID = "id";
    private static final String COLUMN_NAME = "name";

    public DBHelper(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        String query = "CREATE TABLE " + TABLE_NAME + " (" +
                COLUMN_ID + " INTEGER PRIMARY KEY AUTOINCREMENT, " +
                COLUMN_NAME + " TEXT);";
        db.execSQL(query);
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        db.execSQL("DROP TABLE IF EXISTS " + TABLE_NAME);
        onCreate(db);
    }

    public void insertData(String name) {
        SQLiteDatabase db = getWritableDatabase();
        ContentValues values = new ContentValues();
        values.put(COLUMN_NAME, name);
        db.insert(TABLE_NAME, null, values);
        db.close();
    }

    public ArrayList<String> getData() {
        ArrayList<String> dataList = new ArrayList<>();
        SQLiteDatabase db = getReadableDatabase();
        String query = "SELECT * FROM " + TABLE_NAME;
        Cursor cursor = db.rawQuery(query, null);
        if (cursor.moveToFirst()) {
            do {
                String name = cursor.getString(cursor.getColumnIndex(COLUMN_NAME));
                dataList.add(name);
            } while (cursor.moveToNext());
        }
        cursor.close();
        db.close();
        return dataList;
    }
}

2. 在Activity中使用DBHelper类来读取数据并在ListView中显示：

public class MainActivity extends AppCompatActivity {

    private ListView listView;
    private ArrayList<String> dataList;
    private ArrayAdapter<String> adapter;
    private DBHelper dbHelper;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        listView = findViewById(R.id.list_view);
        dataList = new ArrayList<>();
        adapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1, dataList);
        listView.setAdapter(adapter);

        dbHelper = new DBHelper(this);
        dbHelper.insertData("John");
        dbHelper.insertData("Mary");
        dbHelper.insertData("Tom");

        ArrayList<String> list = dbHelper.getData();
        dataList.clear();
        dataList.addAll(list);
        adapter.notifyDataSetChanged();
    }
}

注意：需要在AndroidManifest.xml文件中添加以下权限：

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />