Question

amount is not being set to EditText, only stores in another external variable.

productAtoComplete.setOnItemClickListener(new OnItemClickListener(){
    public void onItemClick(AdapterView<?> parent, View view, int position, long id){
        amount.setText(map.get((String) parent.getItemAtPosition(position)));
    }
});

Answer 1

Do this way:

amount.setText(map.get(position));

or this way:

amount.setText((String) parent.getItemAtPosition(position));