MainActivity

package com.example.demo.autocomplete;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.ArrayAdapter;
import android.widget.AutoCompleteTextView;

public class MainActivity extends AppCompatActivity {
AutoCompleteTextView autoCompleteTextView;
String[] names = {"Rick","Amul","Samul","Denim","Lee"};
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        autoCompleteTextView = findViewById(R.id.autocomplete);
        ArrayAdapter<String> adapter = new ArrayAdapter<>(this,R.layout.support_simple_spinner_dropdown_item,names);
        autoCompleteTextView.setThreshold(2);
        autoCompleteTextView.setAdapter(adapter);

    }
}