ExpandableListView Demo

Android ExpandableListView. Android ExpandableListView is a view that shows items in a vertically scrolling two-level list. It differs from a ListView by allowing two levels which are groups that can be easily expanded and collapsed by touching to view and their respective children items.

==> activity_expandablelistview.xml

<?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"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <android.support.v7.widget.Toolbar
        android:id="@+id/toolbar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="@color/colorPrimary"
        android:titleTextColor="@color/white"
        app:titleTextColor="@color/white"></android.support.v7.widget.Toolbar>

    <ExpandableListView
        android:id="@+id/lvExp"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />


</LinearLayout>


==>list_item.xml (Listview Item Row)

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_gravity="left"
    android:background="#ffffff"
    android:orientation="horizontal" >

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="left"
        android:gravity="left"
        android:orientation="vertical" >

        <TextView
            android:id="@+id/tv_event"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:padding="3dp"
            android:text="TextView"
            android:textColor="#000000"
            android:textSize="16dp"
            android:textStyle="bold" />

        <TextView
            android:id="@+id/tv_date"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_gravity="center"
            android:padding="4dp"
            android:text="TextView" />

    </LinearLayout>


</LinearLayout>

==> ExpandableListAdapter.java

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> _listDataHeader; // header titles
    // child data in format of header title, child title
    private HashMap<String, List<String>> _listDataChild;

    public ExpandableListAdapter(Context context, List<String> listDataHeader,
                                 HashMap<String, List<String>> listChildData) {
        this._context = context;
        this._listDataHeader = listDataHeader;
        this._listDataChild = listChildData;
    }

    @Override
    public Object getChild(int groupPosition, int childPosititon) {
        return this._listDataChild.get(this._listDataHeader.get(groupPosition))
                .get(childPosititon);
    }

    @Override
    public long getChildId(int groupPosition, int childPosition) {
        return childPosition;
    }

    @Override
    public View getChildView(int groupPosition, final int childPosition,
                             boolean isLastChild, View convertView, ViewGroup parent) {

        final String childText = (String) getChild(groupPosition, childPosition);

        if (convertView == null) {
            LayoutInflater infalInflater = (LayoutInflater) this._context
                    .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            convertView = infalInflater.inflate(R.layout.list_item, null);
        }

        TextView txtListChild = (TextView) convertView
                .findViewById(R.id.tv_event);//lblListItem

        txtListChild.setText(childText);
        return convertView;
    }

    @Override
    public int getChildrenCount(int groupPosition) {
        return this._listDataChild.get(this._listDataHeader.get(groupPosition))
                .size();
    }

    @Override
    public Object getGroup(int groupPosition) {
        return this._listDataHeader.get(groupPosition);
    }

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

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

    @Override
    public View getGroupView(int groupPosition, boolean isExpanded,
                             View convertView, ViewGroup parent) {
        String headerTitle = (String) getGroup(groupPosition);
        if (convertView == null) {
            LayoutInflater infalInflater = (LayoutInflater) this._context
                    .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            convertView = infalInflater.inflate(R.layout.list_group, null);
        }

        TextView lblListHeader = (TextView) convertView
                .findViewById(R.id.lblListHeader);
        lblListHeader.setTypeface(null, Typeface.BOLD);
        lblListHeader.setText(headerTitle);

        return convertView;
    }

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

    @Override
    public boolean isChildSelectable(int groupPosition, int childPosition) {
        return true;
    }

}

==> ExpandableListViewActivity.java

import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.widget.ExpandableListView;

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

import butterknife.BindView;
import butterknife.ButterKnife;


public class ExpandableListViewActivity extends AppCompatActivity {

    ExpandableListAdapter listAdapter;

    @BindView(R.id.lvExp)
    ExpandableListView expListView;

    @BindView(R.id.toolbar)
    Toolbar toolbar;

    List<String> listDataHeader;
    HashMap<String, List<String>> listDataChild;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_expandablelistview);
        ButterKnife.bind(this);
        setSupportActionBar(toolbar);
        getSupportActionBar().setTitle("Expandable Listview");
        prepareListData();

        listAdapter = new ExpandableListAdapter(this, listDataHeader, listDataChild);

        // setting list adapter
        expListView.setAdapter(listAdapter);
    }

    private void prepareListData() {
        listDataHeader = new ArrayList<String>();
        listDataChild = new HashMap<String, List<String>>();

        // Adding child data
        listDataHeader.add("Top 250");
        listDataHeader.add("Now Showing");
        listDataHeader.add("Coming Soon..");

        // Adding child data
        List<String> top250 = new ArrayList<String>();
        top250.add("The Shawshank Redemption");
        top250.add("The Godfather");
        top250.add("The Godfather: Part II");
        top250.add("Pulp Fiction");
        top250.add("The Good, the Bad and the Ugly");
        top250.add("The Dark Knight");
        top250.add("12 Angry Men");

        List<String> nowShowing = new ArrayList<String>();
        nowShowing.add("The Conjuring");
        nowShowing.add("Despicable Me 2");
        nowShowing.add("Turbo");
        nowShowing.add("Grown Ups 2");
        nowShowing.add("Red 2");
        nowShowing.add("The Wolverine");

        List<String> comingSoon = new ArrayList<String>();
        comingSoon.add("2 Guns");
        comingSoon.add("The Smurfs 2");
        comingSoon.add("The Spectacular Now");
        comingSoon.add("The Canyons");
        comingSoon.add("Europa Report");

        listDataChild.put(listDataHeader.get(0), top250); // Header, Child data
        listDataChild.put(listDataHeader.get(1), nowShowing);
        listDataChild.put(listDataHeader.get(2), comingSoon);
    }

}