Let's demonstrate a MultiAutoCompleteTextView:
In your layout file you can add it as:

        
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@id/autocomplete"
        android:layout_marginTop="8dp"
        android:hint="multi auto complete text view"
        android:id="@+id/multi"
        android:ems="10"/>

SO, your activity. java can be as:

public class MainActivity extends AppCompatActivity {
    MultiAutoCompleteTextView text1;
    String[] languages={"android", "java","IOS","JDBC","C#","C++","C"};
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        text1=(MultiAutoCompleteTextView) findViewById(R.id.multi);
        ArrayAdapter adapter=new ArrayAdapter(this, android.R.layout.simple_list_item_1,languages);
     
        text.setThreshold(1);
        text1.setTokenizer(new MultiAutoCompleteTextView.CommaTokenizer());

    }
} 

You Can watch a video demo at: