text: /***********************************************************************************************************************
  *  OpenStudio(R), Copyright (c) 2008-2018, Alliance for Sustainable Energy, LLC. All rights reserved.
  *
  *  Redistribution and use in source and binary forms, with or without modification, are permitted provided that the
  *  following conditions are met:
  *
  *  (1) Redistributions of source code must retain the above copyright notice, this list of conditions and the following
  *  disclaimer.
  *
  *  (2) Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following
  *  disclaimer in the documentation and/or other materials provided with the distribution.
  *
  *  (3) Neither the name of the copyright holder nor the names of any contributors may be used to endorse or promote products
  *  derived from this software without specific prior written permission from the respective party.
  *
  *  (4) Other than as required in clauses (1) and (2), distributions in any form of modifications or other derivative works
  *  may not use the "OpenStudio" trademark, "OS", "os", or any other confusingly similar designation without specific prior
  *  written permission from Alliance for Sustainable Energy, LLC.
  *
  *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) AND ANY CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
  *  INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  *  DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S), ANY CONTRIBUTORS, THE UNITED STATES GOVERNMENT, OR THE UNITED
  *  STATES DEPARTMENT OF ENERGY, NOR ANY OF THEIR EMPLOYEES, BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  *  EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
  *  USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  *  STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
  *  ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  ***********************************************************************************************************************/
  
  #include "OSViewSwitcher.hpp"
  
  #include <QBoxLayout>
  #include <QPainter>
  #include <QStackedWidget>
  #include <QStyleOption>
  
  #include "../utilities/core/Assert.hpp"
  
  namespace openstudio {
  
  OSViewSwitcher::OSViewSwitcher(QWidget * parent)
    : QWidget(parent),
      m_view(nullptr)
  {
    auto layout = new QVBoxLayout();
    layout->setContentsMargins(0,0,0,0);
    setLayout(layout);
  
    m_stack = new QStackedWidget();
  
    layout->addWidget(m_stack);
  }
  
  OSViewSwitcher::~OSViewSwitcher()
  {
  }
  
  void OSViewSwitcher::setView(QWidget * view)
  {
    // Evan note: It's bad to play with null pointers
    // Unfortunately, the app crashes if you don't them
    if (!view) {
      //return;
    }
    if( QWidget * widget = m_stack->currentWidget() )
    {
      m_stack->removeWidget( widget );
      // When we determine why there is a crash in Pat frm not
      // using a null pointer, we can again delte these widgets
      //widget->deleteLater();
    }
    OS_ASSERT(m_stack->count() == 0);
  
    m_view = view;
  
    m_stack->addWidget(m_view);
  }
  
  QWidget * OSViewSwitcher::view() const
  {
    return m_view;
  }
  
  void OSViewSwitcher::clear()
  {
    if( m_view )
    {
      m_stack->removeWidget(m_view);
    }
  
    m_view = nullptr;
  }
  
  void OSViewSwitcher::paintEvent(QPaintEvent *)
  {
    QStyleOption opt;
    opt.init(this);
    QPainter p(this);
    style()->drawPrimitive(QStyle::PE_Widget, &opt, &p, this);
  }
  
  }
  