Autocomplete TextView doesnot show suggestions in Textwatcher

Question

I m implementing a feature like WhatsApp group activity. I created an arrayadapter to set in textwatcher in the autocomplete text view. Whenever I press "@" according to my logic the dropdown menu opens but whenever I press any other key, dropdown menu closes without showing the options starting with the pressed key.

I want to add multiple names saved in a string each time as when a user press "@" the dropdown opens to show the list and when any character pressed then it should iterate in the dropdown menu.

Code for my text watcher :-

@Override
        public void afterTextChanged(Editable mEdit)
        {
            ContactFetch = mEdit.toString();


            Log.d("contactFetch",":"+ ContactFetch);
            Log.d("@tyed es","yes");


            if(ContactFetch.endsWith("@")){


                Log.d("hola",": yes");

                adapter = new ArrayAdapter<String>(getApplicationContext(), android.R.layout.select_dialog_item, data);
                editContact1.setThreshold(1);
                editContact1.setTextColor(Color.BLACK);
                editContact1.setAdapter(adapter);
                editContact1.showDropDown();

                    editContact1.setOnItemClickListener(new AdapterView.OnItemClickListener() {

                        @Override
                        public void onItemClick(AdapterView<?> adapterView, android.view.View view, int i, long l) {
                            starttext = adapterView.getItemAtPosition(i).toString();
                            index = i;
                            Log.d("Index of selected", ": " + index);
                            editContact1.setText(content + starttext);
                            editContact1.setSelection(editContact1.getText().length());


                        }

                    });

                adapter.notifyDataSetChanged();