My Experiments

Hi folks,today I would like to share how can we create a AutoCompleteTextView with custom List.
AutoCompleteTextView widget with a simple String objects is just a simple task, but its slightly complicated with custom List. I also faced a similar problem when I tried to implement it. I would like to share how we should get the thing done in few minutes.

Lets get started.
Create a basic project in Android with the name you like. I created it with AutoCompleteDemo.

This should be your activity_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin"
    tools:context=".MainActivity">

    <AutoCompleteTextView
        android:id="@+id/txt_search"
        android:hint="@string/placeholder_search"
        android:completionThreshold="1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />
</RelativeLayout>

Layout for custom row in row_people.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceMedium"
        android:text="Medium Text"
        android:paddingLeft="8dp"
        android:paddingRight="8dp"
        android:paddingTop="16dp"
        android:paddingBottom="16dp"
        android:id="@+id/lbl_name" />
</RelativeLayout>

Lets create a model class.

package com.akshay.autodemo;

/**
 * Created by akshay on 1/2/15.
 * A Simple Model class.
 */
public class People {

    private String name, lastName;
    private int id;

    public People(String name, String lastName, int id) {
        this.name = name;
        this.lastName = lastName;
        this.id = id;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getlastName() {
        return lastName;
    }

    public void setlastName(String lastName) {
        this.lastName = lastName;
    }
}

This is our MainActivity.java

package com.akshay.autodemo;

import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.AutoCompleteTextView;

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

public class MainActivity extends ActionBarActivity {

    AutoCompleteTextView txtSearch;
    List<People> mList;
    PeopleAdapter adapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mList = retrievePeople();
        txtSearch = (AutoCompleteTextView) findViewById(R.id.txt_search);
        txtSearch.setThreshold(1);
        adapter = new PeopleAdapter(this, R.layout.activity_main, R.id.lbl_name, mList);
        txtSearch.setAdapter(adapter);
    }

    private List<People> retrievePeople() {
        List<People> list = new ArrayList<People>();
        list.add(new People("James", "Bond", 1));
        list.add(new People("Jason", "Bourne", 2));
        list.add(new People("Ethan", "Hunt", 3));
        list.add(new People("Sherlock", "Holmes", 4));
        list.add(new People("David", "Beckham", 5));
        list.add(new People("Bryan", "Adams", 6));
        list.add(new People("Arjen", "Robben", 7));
        list.add(new People("Van", "Persie", 8));
        list.add(new People("Zinedine", "Zidane", 9));
        list.add(new People("Luis", "Figo", 10));
        list.add(new People("John", "Watson", 11));
        return list;
    }
}

This is the most awaited Adapter class PeopleAdapter.java

package com.akshay.autodemo;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.Filter;
import android.widget.TextView;

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

/**
 * Created by akshay on 1/2/15.
 */
public class PeopleAdapter extends ArrayAdapter<People> {

    Context context;
    int resource, textViewResourceId;
    List<People> items, tempItems, suggestions;

    public PeopleAdapter(Context context, int resource, int textViewResourceId, List<People> items) {
        super(context, resource, textViewResourceId, items);
        this.context = context;
        this.resource = resource;
        this.textViewResourceId = textViewResourceId;
        this.items = items;
        tempItems = new ArrayList<People>(items); // this makes the difference.
        suggestions = new ArrayList<People>();
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        View view = convertView;
        if (convertView == null) {
            LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            view = inflater.inflate(R.layout.row_people, parent, false);
        }
        People people = items.get(position);
        if (people != null) {
            TextView lblName = (TextView) view.findViewById(R.id.lbl_name);
            if (lblName != null)
                lblName.setText(people.getName());
        }
        return view;
    }

    @Override
    public Filter getFilter() {
        return nameFilter;
    }

    /**
     * Custom Filter implementation for custom suggestions we provide.
     */
    Filter nameFilter = new Filter() {
        @Override
        public CharSequence convertResultToString(Object resultValue) {
            String str = ((People) resultValue).getName();
            return str;
        }

        @Override
        protected FilterResults performFiltering(CharSequence constraint) {
            if (constraint != null) {
                suggestions.clear();
                for (People people : tempItems) {
                    if (people.getName().toLowerCase().contains(constraint.toString().toLowerCase())) {
                        suggestions.add(people);
                    }
                }
                FilterResults filterResults = new FilterResults();
                filterResults.values = suggestions;
                filterResults.count = suggestions.size();
                return filterResults;
            } else {
                return new FilterResults();
            }
        }

        @Override
        protected void publishResults(CharSequence constraint, FilterResults results) {
            List<People> filterList = (ArrayList<People>) results.values;
            if (results != null && results.count > 0) {
                clear();
                for (People people : filterList) {
                    add(people);
                    notifyDataSetChanged();
                }
            }
        }
    };
}

Now there might be question at line no 29 why have created a new object instead of passing tempItems = items. That was the mistake I did, because Collection, Arrays etc are mutable objects i.e Assigment operator is fined for primitive types or immutable objects like String, int, etc if we want to copy a value in another variable. But its not fined in Collections or Arrays becaues they all are mutable object, and any copy of the object points to original object.

We can also use Cloneable Interface to clone the object, but its not recommended approach though its good practice, but it has some pitfalls. I will explain Clone Interface and its working in other post.

Following is output of above program

If you like this article please comment or if you have any problems or if I have commited any mistake please let me know.

Happy Coding.

My Experiments

Experience with Android

How to create AutoCompleteTextView using custom Filter Implementation