Part 2 – Adapter – Coding in Flow

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In part 2 of the Custom AutoCompleteTextView Tutorial, we will create our custom ArrayAdapter, which will be the bridge between our ArrayList of custom objects and the AutoCompleteTextView suggestion list.
For this we will extend the ArrayAdapter class, because it already implements the Filterable and ListAdapter interfaces, and implement our own Filter, where we override the performFiltering, publishResults and convertResultToString methods.
In our ArrayAdapter itself we set this filter in the getFilter method and populate our custom row layout in the getView method.
Lastly we create an instance of our adapter in the MainActivity and set it on our AutoCompleteTextView.

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AutoCompleteCountryAdapter.javaactivity_main.xmlcountry_autocomplete_row.xmlCountryItem.javaMainActivity.java

package com.codinginflow.customautocompleteexample;

import android.content.Context;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.Filter;
import android.widget.ImageView;
import android.widget.TextView;

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


public class AutoCompleteCountryAdapter extends ArrayAdapter<CountryItem> {
    private List<CountryItem> countryListFull;

    public AutoCompleteCountryAdapter(@NonNull Context context, @NonNull List<CountryItem> countryList) {
        super(context, 0, countryList);
        countryListFull = new ArrayList<>(countryList);
    }

    @NonNull
    @Override
    public Filter getFilter() {
        return countryFilter;
    }

    @NonNull
    @Override
    public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {
        if (convertView == null) {
            convertView = LayoutInflater.from(getContext()).inflate(
                    R.layout.country_autocomplete_row, parent, false
            );
        }

        TextView textViewName = convertView.findViewById(R.id.text_view_name);
        ImageView imageViewFlag = convertView.findViewById(R.id.image_view_flag);

        CountryItem countryItem = getItem(position);

        if (countryItem != null) {
            textViewName.setText(countryItem.getCountryName());
            imageViewFlag.setImageResource(countryItem.getFlagImage());
        }

        return convertView;
    }

    private Filter countryFilter = new Filter() {
        @Override
        protected FilterResults performFiltering(CharSequence constraint) {
            FilterResults results = new FilterResults();
            List<CountryItem> suggestions = new ArrayList<>();

            if (constraint == null || constraint.length() == 0) {
                suggestions.addAll(countryListFull);
            } else {
                String filterPattern = constraint.toString().toLowerCase().trim();

                for (CountryItem item : countryListFull) {
                    if (item.getCountryName().toLowerCase().contains(filterPattern)) {
                        suggestions.add(item);
                    }
                }
            }

            results.values = suggestions;
            results.count = suggestions.size();

            return results;
        }

        @Override
        protected void publishResults(CharSequence constraint, FilterResults results) {
            clear();
            addAll((List) results.values);
            notifyDataSetChanged();
        }

        @Override
        public CharSequence convertResultToString(Object resultValue) {
            return ((CountryItem) resultValue).getCountryName();
        }
    };
}

<?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 android.widget.AutoCompleteTextView;

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();

        AutoCompleteTextView editText = findViewById(R.id.actv);
        AutoCompleteCountryAdapter adapter = new AutoCompleteCountryAdapter(this, countryList);
        editText.setAdapter(adapter);
    }

    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));
    }
}