activity_main.xmlcountry_autocomplete_row.xmlCountryItem.javaMainActivity.java
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:padding="16dp"
    tools:context="com.codinginflow.customautocompleteexample.MainActivity">

    <AutoCompleteTextView
        android:id="@+id/actv"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:completionThreshold="1"
        android:hint="Select a country" />

</LinearLayout>
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:padding="4dp">

    <ImageView
        android:id="@+id/image_view_flag"
        android:layout_width="60dp"
        android:layout_height="40dp"
        tools:src="@drawable/flag_afghanistan" />

    <TextView
        android:id="@+id/text_view_name"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="center_vertical"
        android:paddingStart="8dp"
        android:textAppearance="?android:attr/textAppearanceListItemSmall"
        tools:text="Afghanistan" />

</LinearLayout>
package com.codinginflow.customautocompleteexample;

public class CountryItem {
    private String countryName;
    private int flagImage;

    public CountryItem(String countryName, int flagImage) {
        this.countryName = countryName;
        this.flagImage = flagImage;
    }

    public String getCountryName() {
        return countryName;
    }

    public int getFlagImage() {
        return flagImage;
    }
}
package com.codinginflow.customautocompleteexample;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;

import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {
    private List<CountryItem> countryList;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        fillCountryList();
    }

    private void fillCountryList() {
        countryList = new ArrayList<>();
        countryList.add(new CountryItem("Afghanistan", R.drawable.flag_afghanistan));
        countryList.add(new CountryItem("Albania", R.drawable.flag_albania));
        countryList.add(new CountryItem("Algeria", R.drawable.flag_algeria));
        countryList.add(new CountryItem("Andorra", R.drawable.flag_andorra));
        countryList.add(new CountryItem("Angola", R.drawable.flag_angola));
    }
}