C++/Qt/QAbstractItemView

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Subclass QAbstractItemView

  

Foundations of Qt Development\Chapter05\singleitemview\main.cpp
/*
 * Copyright (c) 2006-2007, Johan Thelin
 * 
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without modification, 
 * are permitted provided that the following conditions are met:
 * 
 *     * Redistributions of source code must retain the above copyright notice, 
 *       this list of conditions and the following disclaimer.
 *     * 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.
 *     * Neither the name of APress nor the names of its contributors 
 *       may be used to endorse or promote products derived from this software 
 *       without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND 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 OWNER OR
 * CONTRIBUTORS 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 <QApplication>
#include <QSplitter>
#include <QTableView>
#include <QStandardItemModel>
#include "singleitemview.h"
int main( int argc, char **argv )
{
  QApplication app( argc, argv );
  
  QTableView *table = new QTableView();
  SingleItemView *selectionView = new SingleItemView();
  
  QSplitter splitter;
  splitter.addWidget( table );
  splitter.addWidget( selectionView );
  QStandardItemModel model( 5, 2 );
  for( int r=0; r<5; r++ ) 
    for( int c=0; c<2; c++) 
    {
      QStandardItem *item = new QStandardItem( QString("Row:%0, Column:%1").arg(r).arg(c) );      
      model.setItem(r, c, item);
    }
  table->setModel( &model );
  selectionView->setModel( &model );
  selectionView->setSelectionModel( table->selectionModel() );
  splitter.show();
  
  return app.exec();
}

Foundations of Qt Development\Chapter05\singleitemview\singleitemview.cpp
/*
 * Copyright (c) 2006-2007, Johan Thelin
 * 
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without modification, 
 * are permitted provided that the following conditions are met:
 * 
 *     * Redistributions of source code must retain the above copyright notice, 
 *       this list of conditions and the following disclaimer.
 *     * 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.
 *     * Neither the name of APress nor the names of its contributors 
 *       may be used to endorse or promote products derived from this software 
 *       without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND 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 OWNER OR
 * CONTRIBUTORS 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 <QScrollBar>
#include <QGridLayout>
#include <QLabel>
#include "singleitemview.h"
SingleItemView::SingleItemView( QWidget *parent ) : QAbstractItemView( parent )
{
  QGridLayout *layout = new QGridLayout( this->viewport() );
  label = new QLabel();
  layout->addWidget( label, 0, 0 );
  
  label->setAlignment( Qt::AlignCenter );
  label->setSizePolicy( QSizePolicy( QSizePolicy::Expanding, QSizePolicy::Expanding ) );
  label->setText( tr("<i>No data.</i>") );
}
 
QRect SingleItemView::visualRect( const QModelIndex &index ) const
{
  if( selectionModel()->selection().indexes().count() != 1 )
    return QRect();
    
  if( currentIndex() != index )
    return QRect();
    
  return rect();  
}
QRegion SingleItemView::visualRegionForSelection( const QItemSelection &selection ) const
{
  if( selection.indexes().count() != 1 )
    return QRect();
    
  if( currentIndex() != selection.indexes()[0] )
    return QRect();
    
  return rect();
}
bool SingleItemView::isIndexHidden( const QModelIndex &index ) const
{
  if( selectionModel()->selection().indexes().count() != 1 )
    return true;
    
  if( currentIndex() != index )
    return true;
    
  return false;
}
QModelIndex SingleItemView::indexAt( const QPoint &point ) const
{
  if( selectionModel()->selection().indexes().count() != 1 )
    return QModelIndex();
    
  return currentIndex();  
}
int SingleItemView::horizontalOffset() const
{
  return horizontalScrollBar()->value();
}
int SingleItemView::verticalOffset() const
{
  return verticalScrollBar()->value();
}
QModelIndex SingleItemView::moveCursor( CursorAction cursorAction, Qt::KeyboardModifiers modifiers )
{
  return currentIndex();
}
void SingleItemView::setSelection( const QRect &rect, QItemSelectionModel::SelectionFlags flags )
{
  // do nothing
}
void SingleItemView::scrollTo( const QModelIndex &index, ScrollHint hint )
{
  // cannot scroll
}
void SingleItemView::dataChanged( const QModelIndex &topLeft, const QModelIndex &bottomRight )
{
  updateText();  
}
void SingleItemView::selectionChanged( const QItemSelection &selected, const QItemSelection &deselected )
{
  updateText();
}
void SingleItemView::updateText()
{
  switch( selectionModel()->selection().indexes().count() )
  {
    case 0:
      label->setText( tr("<i>No data.</i>") );
      break;
      
    case 1:
      label->setText( model()->data( currentIndex() ).toString() );
      break;
      
    default:
      label->setText( tr("<i>Too many items selected.<br>Can only show one item at a time.</i>") );
      break;
  }
}

Foundations of Qt Development\Chapter05\singleitemview\singleitemview.h
/*
 * Copyright (c) 2006-2007, Johan Thelin
 * 
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without modification, 
 * are permitted provided that the following conditions are met:
 * 
 *     * Redistributions of source code must retain the above copyright notice, 
 *       this list of conditions and the following disclaimer.
 *     * 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.
 *     * Neither the name of APress nor the names of its contributors 
 *       may be used to endorse or promote products derived from this software 
 *       without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND 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 OWNER OR
 * CONTRIBUTORS 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.
 *
 */
#ifndef SINGLEITEMVIEW_H
#define SINGLEITEMVIEW_H
#include <QAbstractItemView>
class QLabel;
class SingleItemView : public QAbstractItemView
{
  Q_OBJECT
  
public:
  SingleItemView( QWidget *parent = 0 );
  
  QModelIndex indexAt( const QPoint &point ) const;
  void scrollTo( const QModelIndex &index, ScrollHint hint = EnsureVisible );
  QRect visualRect( const QModelIndex &index ) const;
protected:
  int horizontalOffset() const;
  bool isIndexHidden( const QModelIndex &index ) const;
  QModelIndex moveCursor( CursorAction cursorAction, Qt::KeyboardModifiers modifiers );
  void setSelection( const QRect &rect, QItemSelectionModel::SelectionFlags flags );
  int verticalOffset() const;
  QRegion visualRegionForSelection( const QItemSelection &selection ) const;
    
protected slots:
  void dataChanged( const QModelIndex &topLeft, const QModelIndex &bottomRight );
  void selectionChanged( const QItemSelection &selected, const QItemSelection &deselected );
  
private:
  void updateText();
  
  QLabel *label;
};
#endif // SINGLEITEMVIEW_H