Expandable Listview - Checking CheckBox in group and child

I am in developing an expandable listview with checkbox in group and child. My Goal is when checkbox in group is checked, so the checkbox in child is checked too. But now I have problem: if the checkbox in group is checked, the child will be checked if I scroll the list after I see all child..

Can anybody help me to solve this problem? Thanks in advance.

This is My Adapter:

public class AdapterHistoryExpandable extends BaseExpandableListAdapter {

private Context context;
private boolean checkAll = false;
private ArrayList<GroupItemsInfo> teamName;
public int isGroupChecked = 0;
HistoryHeaderActivity main;
TotalListener mListener;

class ViewHolder {
    public CheckBox checkChild, checkGroup;
    public TextView date, h_ps_id, h_ps_name, h_dokname, h_item, h_qty, h_service, heading;
}

public AdapterHistoryExpandable(HistoryHeaderActivity main, ArrayList<GroupItemsInfo> deptList) {
    this.main = main;
    this.teamName = deptList;
}

@Override
public void registerDataSetObserver(DataSetObserver observer) {
}

@Override
public void unregisterDataSetObserver(DataSetObserver observer) {
}

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

@Override
public int getChildrenCount(int groupPosition) {
    ArrayList<ChildItemsInfo> productList = teamName.get(groupPosition).getSongName();
    return productList.size();
}

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

@Override
public Object getChild(int groupPosition, int childPosition) {
    ArrayList<ChildItemsInfo> productList = teamName.get(groupPosition).getSongName();
    return productList.get(childPosition);
}

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

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

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

public void setmListener(TotalListener mListener) {
    this.mListener = mListener;
}

public void setmGroupList(ArrayList<GroupItemsInfo> mGroupList) {
    this.teamName = mGroupList;
}

@Override
public View getGroupView(final int groupPosition, final boolean isExpanded, View convertView, ViewGroup parent) {
    final ViewHolder holder;
    final GroupItemsInfo headerInfo = (GroupItemsInfo) getGroup(groupPosition);
    if (convertView == null) {
        holder = new ViewHolder();
        LayoutInflater inflater = (LayoutInflater) main.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        convertView = inflater.inflate(R.layout.group_items, null);
        holder.checkGroup = (CheckBox) convertView.findViewById(R.id.checkList);
        holder.checkGroup.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {

            @Override
            public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
                if (!isExpanded)
                    mListener.expandGroupEvent(groupPosition, isExpanded);
                int getPosition = (Integer) buttonView.getTag();
                headerInfo.setSelected(isChecked);

                if (!isChecked) {
                    headerInfo.setSelected(false);
                }
                Intent intent = new Intent(context, AdapterHistoryExpandable.class);
                intent.addFlags(Intent.FLAG_ACTIVITY_NO_ANIMATION);
                context.startActivity(intent);
            }
        });
        convertView.setTag(holder);
        convertView.setTag(R.id.checkList, holder.checkGroup);
        convertView.setTag(holder);
    } else {
        holder = (ViewHolder) convertView.getTag();
    }
    holder.heading = (TextView) convertView.findViewById(R.id.heading);
    holder.checkGroup.setTag(groupPosition);
    holder.checkGroup.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
        @Override
        public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
            main.groupInfos.get(groupPosition).setSelected(buttonView.isChecked());
        }
    });
    holder.checkGroup.setChecked(main.groupInfos.get(groupPosition).isSelected());

    holder.heading.setText(headerInfo.getName().trim());
    return convertView;
}

@Override
public View getChildView(final int groupPosition, final int childPosition, boolean isLastChild, View convertView, ViewGroup parent) {
    final ChildItemsInfo detailInfo = (ChildItemsInfo) getChild(groupPosition, childPosition);
    final ViewHolder holder;
    if (convertView == null) {
        LayoutInflater inflater = (LayoutInflater) main.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        convertView = inflater.inflate(R.layout.list_history, null);
        holder = new ViewHolder();
        convertView.setTag(holder);
    } else {
        holder = (ViewHolder) convertView.getTag();
    }
    holder.date = (TextView) convertView.findViewById(R.id.date_);
    holder.h_ps_id = (TextView) convertView.findViewById(R.id.patient_id);
    holder.h_ps_name = (TextView) convertView.findViewById(R.id.patient_);
    holder.h_dokname = (TextView) convertView.findViewById(R.id.doctor_);
    holder.h_item = (TextView) convertView.findViewById(R.id.item_);
    holder.h_qty = (TextView) convertView.findViewById(R.id.qty_);
    holder.h_service = (TextView) convertView.findViewById(R.id.servicetype_);
    holder.checkChild = (CheckBox) convertView.findViewById(R.id.checkBox);

    ModelChecking add = new ModelChecking();
    if (main.groupInfos.get(groupPosition).isSelected()) {
        holder.checkChild.setChecked(true);
        if (holder.checkChild.isChecked()) {
            add.setIDItem(detailInfo.getHitem());
            add.setQtyItem(detailInfo.getHqty());
            main.checkingItem.add(add);
        }
    } else {
        holder.checkChild.setChecked(false);
        main.checkingItem.clear();

    }

    holder.h_ps_id.setText(detailInfo.getHp_id().trim());
    holder.date.setText(detailInfo.getDate().trim());
    holder.h_ps_name.setText(detailInfo.getHp_name().trim());
    holder.h_dokname.setText(detailInfo.getHd_name().trim());
    holder.h_item.setText(detailInfo.getHitem().trim());
    holder.h_qty.setText(detailInfo.getHqty().trim());
    holder.h_service.setText(detailInfo.getHservice().trim());

    return convertView;
}

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

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

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

@Override
public void onGroupExpanded(int groupPosition) {

}

@Override
public void onGroupCollapsed(int groupPosition) {

}

@Override
public long getCombinedChildId(long groupId, long childId) {
    return 0;
}

@Override
public long getCombinedGroupId(long groupId) {
    return 0;
}

}