MyDataBase.java

public class MyDatabase {

    private DatabaseHelper databaseHelper;
    private SQLiteDatabase database;

    private ArrayList<String> districtList;

    public MyDatabase(Context context) {
        databaseHelper=new DatabaseHelper(context,"mydb.db");
        database=databaseHelper.getReadableDatabase();
    }

    //Example of getting a list from database
    public ArrayList<String> getDistrictList() {
        districtList=new ArrayList<>();
        
        String query="SELECT * FROM districtName ";
        Cursor cursor=database.rawQuery(query,null);
        if (cursor.moveToFirst())
        {
            do {
                districtList.add(cursor.getString(cursor.getColumnIndex("name")));
            }while (cursor.moveToNext());
        }
        return districtList;
    }
}