public class ExpandableListAdapter extends BaseExpandableListAdapter {

Activity context;
ArrayList<String> s_date,c_number,d_ration,s_time,download_path,a_number,a_name;
String id[];
String mUrl;

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

public ExpandableListAdapter(Activity context, ArrayList<String> start_date, ArrayList<String> caller_number, ArrayList<String> duration,ArrayList<String> start_time, ArrayList<String> download_path, ArrayList<String> agent_number, ArrayList<String> agent_name) {
    this.context=context;
    this.s_date=start_date;
    this.c_number=caller_number;
    this.d_ration=duration;
    this.s_time=start_time;
    this.download_path=download_path;
    this.a_number=agent_number;
    this.a_name=agent_name;
}

@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(final 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);
    }

    Button play_button=(Button) convertView.findViewById(R.id.play);
    play_button.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {

            Log.d("play child is",childText);

        }
    });

    Button download_button=(Button) convertView.findViewById(R.id.download);
    download_button.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {

            Log.d("download child is",childText);

        }
    });

}

@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.s_date.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 start_date = (TextView) convertView.findViewById(R.id.start_date);
    start_date.setText(s_date.get(groupPosition));
    TextView caller_number = (TextView) convertView.findViewById(R.id.caller_number);
    caller_number.setText(c_number.get(groupPosition));
    TextView duration = (TextView) convertView.findViewById(R.id.duration);
    duration.setText(d_ration.get(groupPosition));
    TextView start_time = (TextView) convertView.findViewById(R.id.start_time);
    start_time.setText(s_time.get(groupPosition));
    TextView agent_name = (TextView) convertView.findViewById(R.id.agent_name);
    agent_name.setText(a_name.get(groupPosition));
    TextView agent_number = (TextView) convertView.findViewById(R.id.agent_number);
    agent_number.setText(a_number.get(groupPosition));
   // start_date.setTypeface(null, Typeface.BOLD);
   // start_date.setText(headerTitle);

    return convertView;
}


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

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

ExpandableListAdapter a=new ExpandableListAdapter(MainScreen.this,start_date,caller_number,duration,start_time,download_path,agent_number,agent_name);
    data_list.setAdapter(a);