How to force user to enter only autocomplete suggested list item only?

问题

I am using Autocompltetextview and I want user to allow only to accept the value of suggested list. User should not enter other value and submit. if user did not select the value of autocomplettextview then i want to show toast. can any one help me to solve this . check my snippet code and help me?

Code

actv = (AutoCompleteTextView)rootView.findViewById(R.id.search_donor_area);
        actv.setThreshold(1);//will start working from first character

        materialDesignSpinner.addTextChangedListener(new TextWatcher() {
            @Override
            public void beforeTextChanged(CharSequence s, int start, int count, int after) {

            }

            @Override
            public void onTextChanged(CharSequence s, int start, int before, int count) {

            }

            @Override
            public void afterTextChanged(Editable s) {
                sel_blood_group=materialDesignSpinner.getText().toString();
                Log.d("sel_blood_group",sel_blood_group);

            }
        });
        citymaterialDesignSpinner = (MaterialBetterSpinner)
                rootView.findViewById(R.id.search_donor_city);

        citymaterialDesignSpinner.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
               // Log.d("POSITION", CITY_SPINNERLIST[position]);

                sel_city=citymaterialDesignSpinner.getText().toString();
                Log.d("search_sel_city",sel_city);

                if (position == 0) {

                    //Creating the instance of ArrayAdapter containing list of fruit names
                    ArrayAdapter<String> areasadapter = new ArrayAdapter<String>
                            (getActivity(), android.R.layout.select_dialog_item, AREA_DONOR);

                    actv.setAdapter(areasadapter);//setting the adapter data into the AutoCompleteTextView

                } else if (position == 1) {
                    //Creating the instance of ArrayAdapter containing list of fruit names
                    ArrayAdapter<String> areasadapter = new ArrayAdapter<String>
                            (getActivity(), android.R.layout.select_dialog_item, AREA_DONOR_RAJKOT);

                    actv.setAdapter(areasadapter);//setting the adapter data into the AutoCompleteTextView

                }
                else if (position == 2) {
                    //Creating the instance of ArrayAdapter containing list of fruit names
                    ArrayAdapter<String> areasadapter = new ArrayAdapter<String>
                            (getActivity(), android.R.layout.select_dialog_item, AREA_DONOR_SURAT);

                    actv.setAdapter(areasadapter);//setting the adapter data into the AutoCompleteTextView

                }
                else if (position == 3) {
                    //Creating the instance of ArrayAdapter containing list of fruit names
                    ArrayAdapter<String> areasadapter = new ArrayAdapter<String>
                            (getActivity(), android.R.layout.select_dialog_item, AREA_DONOR_BARODA);

                    actv.setAdapter(areasadapter);//setting the adapter data into the AutoCompleteTextView

                }
            }
        });



        ArrayAdapter<String> cityarrayAdapter = new ArrayAdapter<String>(getActivity(),
                android.R.layout.simple_dropdown_item_1line, CITY_SPINNERLIST);

        citymaterialDesignSpinner.setAdapter(cityarrayAdapter);



        actv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                Log.e("========>>", actv.getText().toString());
                sel_area=actv.getText().toString();
            }
        });




        search_button = (Button)rootView.findViewById(R.id.search_button);

来源：https://stackoverflow.com/questions/46377123/how-to-force-user-to-enter-only-autocomplete-suggested-list-item-only