passing a parameter from MainActivity.java into my SQLiteOpenHelper class

I have set up my SQLiteOpenHelper class and all working ok to retrieve all data in the sqLite database. I now want tp pass a parameter from mainActivity into my SQLiteOpenHelper class to find certain records. User will enter search criteria into a field and i want to pass that user entry to be searched. Currently i have hard coded to search for category 161 but this is where i want to be able to use the parameter passed by the user. I have put my SQLiteOpenerHelper code and my mainActivty code below. I have tried passing a parameter into the getAllUsers() in mainActivity file but Android will not accept parameters. Can someone please help in showing me what i need to do to pass the parameter i need into the sqLite query

SQLiteOpenHelper class

public ArrayList<HashMap<String, String>> getAllUsers() {
        ArrayList<HashMap<String, String>> usersList;
        usersList = new ArrayList<HashMap<String, String>>();
        String[] columns = {"id", "company", "firstname", "lastname", "category"};

        SQLiteDatabase database = this.getWritableDatabase();
        Cursor cursor = database.query("members", columns, "category = 161", null, null, null, "company");
        if (cursor.moveToFirst()) {
            do {
                HashMap<String, String> map = new HashMap<String, String>();
                map.put("id", cursor.getString(0));
                map.put("company", cursor.getString(1));
                map.put("firstname", cursor.getString(2));
                map.put("lastname", cursor.getString(3));
                map.put("category", cursor.getString(4));

                usersList.add(map);
            } while (cursor.moveToNext());
        }
        database.close();
        return usersList;
    }

mainActivity.java

@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        // Get User records from SQLite DB
        ArrayList<HashMap<String, String>> userList = controller.getAllUsers();