Expandable Listview in Android

ExpandableListView is an Android container available as part of the platform. It will be useful to display grouped set of items. On click of the group titles the child elements will be expanded.

Sample Code:

File: 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="com.javapapers.android.expandablelistview.app.MainActivity">

    <ExpandableListView        android:id="@+id/expandableListView"        android:layout_height="match_parent"        android:layout_width="match_parent"        android:indicatorLeft="?android:attr/expandableListPreferredItemIndicatorLeft"        android:divider="#A4C739"        android:dividerHeight="0.5dp" />

</RelativeLayout>

File: list_group.xml

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent">

    <TextView
        android:id="@+id/listTitle"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:paddingLeft="?android:attr/expandableListPreferredItemPaddingLeft"
        android:textColor="#A4C739"
        android:paddingTop="10dp"
        android:paddingBottom="10dp" />


</LinearLayout>

File: list_item.xml

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="wrap_content">
    <TextView
        android:id="@+id/expandedListItem"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:paddingLeft="?android:attr/expandableListPreferredChildPaddingLeft"
        android:paddingTop="10dp"
        android:paddingBottom="10dp" />
</LinearLayout>

File: MainActivity.java

package com.sneha.expandablelistview;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.ExpandableListView;
import android.widget.ExpandableListView.OnChildClickListener;
import android.widget.ExpandableListView.OnGroupCollapseListener;
import android.widget.ExpandableListView.OnGroupExpandListener;
import android.widget.Toast;

public class MainActivity extends Activity
{
    ExpandableListView expandableListView;
    ExpandableListAdapter expandableListAdapter;
    List<String> expandableListTitle;
    HashMap<String, List<String>> expandableListDetail;

    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        expandableListView = (ExpandableListView) findViewById(R.id.expandableListView);
        expandableListDetail = ExpandableListDataPump.getData();
        expandableListTitle = new ArrayList<String>(expandableListDetail.keySet());
        expandableListAdapter = new ExpandableListAdapter(this, expandableListTitle, expandableListDetail);
        expandableListView.setAdapter(expandableListAdapter);
        expandableListView.setOnGroupExpandListener(new OnGroupExpandListener()
        {
            @Override
            public void onGroupExpand(int groupPosition)
            {
                Toast.makeText(getApplicationContext(), expandableListTitle.get(groupPosition) + " List Expanded.", Toast.LENGTH_SHORT).show();
            }
        });

        expandableListView.setOnGroupCollapseListener(new OnGroupCollapseListener()
        {
            @Override
            public void onGroupCollapse(int groupPosition)
            {
                Toast.makeText(getApplicationContext(), expandableListTitle.get(groupPosition) + " List Collapsed.", Toast.LENGTH_SHORT).show();
            }
        });

        expandableListView.setOnChildClickListener(new OnChildClickListener()
        {
            @Override
            public boolean onChildClick(ExpandableListView parent, View v, int groupPosition, int childPosition, long id)
            {
                Toast.makeText(getApplicationContext(), expandableListTitle.get(groupPosition)
                                + " -> " + expandableListDetail.get(expandableListTitle.get(groupPosition)).
                                get(childPosition), Toast.LENGTH_SHORT).show();
                return false;
            }
        });
    }
}

File: ExpandableListAdapter.java

package com.sneha.expandablelistview;

import java.util.HashMap;
import java.util.List;
import android.content.Context;
import android.graphics.Typeface;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseExpandableListAdapter;
import android.widget.TextView;

public class ExpandableListAdapter extends BaseExpandableListAdapter
{
    private Context context;
    private List<String> expandableListTitle;
    private HashMap<String, List<String>> expandableListDetail;

    public ExpandableListAdapter(Context context, List<String> expandableListTitle, HashMap<String, List<String>> expandableListDetail)
    {
        this.context = context;
        this.expandableListTitle = expandableListTitle;
        this.expandableListDetail = expandableListDetail;
    }

    @Override
    public Object getChild(int listPosition, int expandedListPosition)
    {
        return this.expandableListDetail.get(this.expandableListTitle.get(listPosition)).get(expandedListPosition);
    }

    @Override
    public long getChildId(int listPosition, int expandedListPosition)
    {
        return expandedListPosition;
    }

    @Override
    public View getChildView(int listPosition, final int expandedListPosition, boolean isLastChild, View convertView, ViewGroup parent)
    {
        final String expandedListText = (String) getChild(listPosition, expandedListPosition);
     
        if (convertView == null)
        {
            LayoutInflater layoutInflater = (LayoutInflater) this.context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            convertView = layoutInflater.inflate(R.layout.list_item, null);
        }
        TextView expandedListTextView = (TextView) convertView.findViewById(R.id.expandedListItem);
        expandedListTextView.setText(expandedListText);
        return convertView;
    }

    @Override
    public int getChildrenCount(int listPosition)
    {
        return this.expandableListDetail.get(this.expandableListTitle.get(listPosition)).size();
    }

    @Override
    public Object getGroup(int listPosition)
    {
        return this.expandableListTitle.get(listPosition);
    }

    @Override
    public int getGroupCount()
    {
        return this.expandableListTitle.size();
    }

    @Override
    public long getGroupId(int listPosition)
    {
        return listPosition;
    }

    @Override
    public View getGroupView(int listPosition, boolean isExpanded, View convertView, ViewGroup parent)
    {
        String listTitle = (String) getGroup(listPosition);
     
        if (convertView == null)
        {
            LayoutInflater layoutInflater = (LayoutInflater) this.context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            convertView = layoutInflater.inflate(R.layout.list_group, null);
        }
        TextView listTitleTextView = (TextView) convertView.findViewById(R.id.listTitle);
        listTitleTextView.setTypeface(null, Typeface.BOLD);
        listTitleTextView.setText(listTitle);
        return convertView;
    }

    @Override
    public boolean hasStableIds()
    {
        return false;
    }

    @Override
    public boolean isChildSelectable(int listPosition, int expandedListPosition)
    {
        return true;
    }
}

Output:

Download Full Source Code: ExpandableListview

Enjoy Coding...!!!