Expandable listview is used to categorise data in some specific type. Expandable list can have a two level scrolling list. Using ChildDivider feature we divide list items with drawables or colors, and ChildIndicator & GroupIndicator is for start, end , left and right bounds.

activity_main.xml

<?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="match_parent"
    android:orientation="vertical"
    android:background="#f4f4f4" >

    <ExpandableListView
        android:id="@+id/lvExpandable"
        android:layout_height="match_parent"
        android:layout_width="match_parent"
        android:childDivider="#EA8949"
        android:childIndicatorEnd="14.5sp"
        android:childIndicatorLeft="14.5sp"
        android:childIndicatorRight="14.5sp"
        android:childIndicatorStart="14.5sp"
        android:indicatorEnd="14.5sp"
        android:indicatorLeft="14.5sp"
        android:indicatorRight="14.5sp"
        android:indicatorStart="14.5sp"/>

</LinearLayout>

MainActivity.class having Expandable ListView

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

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

        expandableListView = (ExpandableListView)findViewById(R.id.lvExpandable);
        prepareListData();
        expandableListAdapter = new ExpandableListAdapter(this, listGroup, listItem);
        expandableListView.setAdapter(expandableListAdapter);

        // ListView onChild Click Listener
        expandableListView.setOnChildClickListener(new ExpandableListView.OnChildClickListener() {
            @Override
            public boolean onChildClick(ExpandableListView parent, View v, int groupPosition, int childPosition, long id) {
                // your text
                return false;
            }
        });

        // Used for being notified when a group is expanded
        expandableListView.setOnGroupExpandListener(new ExpandableListView.OnGroupExpandListener() {
            @Override
            public void onGroupExpand(int groupPosition) {
                // your text
            }
        });

        // Used for being notified when a group is collapsed
        expandableListView.setOnGroupCollapseListener(new ExpandableListView.OnGroupCollapseListener() {
            @Override
            public void onGroupCollapse(int groupPosition) {
                // your text
            }
        });

        // ListView onGroup Click Listener
        expandableListView.setOnGroupClickListener(new ExpandableListView.OnGroupClickListener() {
            @Override
            public boolean onGroupClick(ExpandableListView parent, View v, int groupPosition, long id) {
                // your text
                return false;
            }
        });
    }

    public void prepareListData(){
        listGroup = new ArrayList<>();
        listItem = new HashMap<String, List<String>>();

        listGroup.add("first list header");
        listGroup.add("second list header");
        listGroup.add("third list header");

        List<String> first = new ArrayList<>();
        first.add("first sub heading");
        first.add("second sub heading");
        first.add("third sub heading");

        List<String> second = new ArrayList<>();
        second.add("first sub heading");
        second.add("second sub heading");
        second.add("third sub heading");

        List<String> third = new ArrayList<>();
        third.add("first sub heading");
        third.add("second sub heading");
        third.add("third sub heading");

        listItem.put(listGroup.get(0), first);
        listItem.put(listGroup.get(1), second);
        listItem.put(listGroup.get(2), third);
    }
}

list_group.xml layout for group

<?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:orientation="vertical"
    android:padding="8dp"
    android:background="#5698BD">

    <TextView
        android:id="@+id/tvListHeader"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:paddingLeft="?android:attr/expandableListPreferredItemPaddingLeft"
        android:textSize="17dp"
        android:textColor="#f9f93d" />

</LinearLayout>

list_itm.xml layout for child items

<?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="55dp"
    android:orientation="vertical" >

    <TextView
        android:id="@+id/tvListItem"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="17dp"
        android:paddingTop="5dp"
        android:paddingBottom="5dp"
        android:paddingLeft="?android:attr/expandableListPreferredChildPaddingLeft" />

</LinearLayout>

ExpandableListAdapter.class custom adapter class to create listview which extends BaseExpandableListAdapter.class

public class ExpandableListAdapter extends BaseExpandableListAdapter {

    private Context context;
    private List<String> listGroup;
    private HashMap<String, List<String>> listItem;

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

    @Override
    public Object getChild(int groupPosition, int childPosititon) {
        return this.listItem.get(this.listGroup.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.tvListItem);

        txtListChild.setText(childText);
        return convertView;
    }

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

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

    @Override
    public int getGroupCount() {
        return this.listGroup.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.tvListHeader);
        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;
    }
}