For example, is there any potential risk in the following code?
Qt Code: 
  1. // when re-implement QCalendarWidget's functions
  2. QObjectList children_of_this = this->children();
  3.   //this points to QCalendarWidget
  4.     for( int i = 0; i < children_of_this.count(); i++)
  5.     {
  6.         if(children_of_this.at(i)->objectName() == "qt_calendar_navigationbar")
  7.            {
  8.             navigator = qobject_cast<QWidget*>(children_of_this[i]);
  9.             if(navigator)
  10.              {
  11.                // do something to navigator's layout
  12.               }
  13.              //navigator is a pointer to a QWidget, which is previous NULL
  14.         if(children_of_this.at(i)->objectName() == "qt_calendar_calendarview")
  15.              {
  16.             view = qobject_cast<QTableView*>(children_of_this[i]);
  17.             if(view)
  18.                       {
  19.                       view->setItemDelegate(new QStyledItemDelegate);
  20.                        }
  21.               }
  22.              //view is a pointer to a QTableView which is previous NULL
  23.     }
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and in the "qcalendarwidget.cpp", the Qt's source code:
Qt Code: 
  1. //i want to access objects like this
  2.     d->m_view->setObjectName(QLatin1String("qt_calendar_calendarview"));
  3.  
  4.     navBarBackground = new QWidget(widget);
  5.     navBarBackground->setObjectName(QLatin1String("qt_calendar_navigationbar"));
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I'm quite new to both Qt and C++ and wondering whether or not it is right to get the objects pointers those are not exposed to users.