Radio-Buttons in ExpandableListView

I try to do radio-buttons in expandable list view. Some children are with checkboxes, but some with radio-button. And i need them to act like radio group. What's wrong with my code? ( added it in ChildView)

 if(rad_group.equals("rg1")) { //children, that should have radio-button

        rbut.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
            @Override
            public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {

                if (rbut.isChecked()) {
                    mSelectedChildPosition = childPosition;
                    mSelectedGroupPosition = groupPosition;
                    notifyDataSetChanged();
                }
            }
        });


        if (mSelectedChildPosition != childPosition && mSelectedGroupPosition != groupPosition) {
            rbut.setChecked(false);
        } else {
            rbut.setChecked(true);
            if (mSelectedRB != null && rbut != mSelectedRB) {
                mSelectedRB = rbut;
            }
        }
    }