@Override
    public boolean onGroupClick(ExpandableListView parent, View v, int groupPosition, long id) {
        Log.d("Clicked on item: ", ""+groupPosition);
        return false;
    }
});

<LinearLayout
        android:layout_below="@id/qtd_prc_cont"
        android:layout_width="match_parent" android:layout_height="wrap_content" android:gravity="center">
        <Textview
            android:layout_width="wrap_content" android:layout_height="wrap_content"  android:id="@+id/group_text" android:text="Group 1"
        <Button
            android:id="@+id/btn_reject"
            android:layout_width="90dp" android:layout_height="30dp" android:text="Reject" android:textAllCaps="false" android:background="@drawable/reject_button_styles"
            android:layout_marginRight="60dp" android:textColor="#a1a2a1" android:textSize="13dp"/>
        <Button
            android:id="@+id/btn_accept"
            android:layout_width="90dp" android:layout_height="30dp" android:text="Accept" android:textAllCaps="false" android:background="@drawable/button_radius"
            android:textColor="@color/colorWhite" android:textSize="13dp"/>
    </LinearLayout>