ListView WOn't refresh using notifyDataSetChanged

I'm trying to refresh the listview from the adapter class ( non activity class) I tried notifyDataSetChanged() but it wont work , I also tried to call the displayListView() in the adapter class but it crashes as well

this is my displayListView() Method in The ActivityClass

    Cursor cursor = dbHelper.fetchAllCountries();

    // The desired columns to be bound
    String[] columns = new String[]{
           DBAdapter.qty,
           DBAdapter.price,
           DBAdapter.PRODUCT_NAME
    };

    // the XML defined views which the data will be bound to
    int[] to = new int[]{
            R.id.qtyL,
            R.id.priceL,
            R.id.PRODUCT_NAMEL
    };

    // create the adapter using the cursor pointing to the desired data
    //as well as the layout information
    dataAdapter = new SimpleCursorAdapter(
            this, R.layout.country_inf,
            cursor,
            columns,
            to,
            0);

    HorizontalListView listView = (HorizontalListView) findViewById(R.id.cartCeckOutList);
    // Assign adapter to ListView
            listView.setAdapter(dataAdapter);
            dataAdapter.notifyDataSetChanged();

And this is the Adapter Class I use

public class CustomListAdapter extends BaseAdapter {

  /////////// Some Code


    plus.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            String the_qty = qty.getText().toString();
            int my_qty = Integer.parseInt(the_qty) + 1;
            qty.setText(my_qty + "");

        }
    });


                    else {

                myADapterDB.checkIfExcist(activity, "productName", myTitle,
                        myQTY, myPrice, m.getPrice(), myTitle, myCategory,
                        myCategoryN + "", myQTY);
                myADapterDB.deleteZeroOrLessValues();


            }

        }
    });

    return convertView;
}

@Override
public void notifyDataSetChanged() {
    // TODO Auto-generated method stub
    super.notifyDataSetChanged();
}

}