C++/Qt/QDesignerCustomWidgetInterface

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extends QDesignerCustomWidgetInterface

  
Foundations of Qt Development\Chapter06\designerplugin\circlebar.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 <QPaintEvent>
#include <QWheelEvent>
#include <QPainter>
#include "circlebar.h"
CircleBar::CircleBar( QWidget *parent ) : QWidget( parent )
{
  m_value = 0;
  
  QSizePolicy policy( QSizePolicy::Preferred, QSizePolicy::Preferred );
  policy.setHeightForWidth( true );
  setSizePolicy( policy );
}
CircleBar::CircleBar( int value, QWidget *parent ) : QWidget( parent )
{
  m_value = value;
  
  QSizePolicy policy( QSizePolicy::Preferred, QSizePolicy::Preferred );
  policy.setHeightForWidth( true );
  setSizePolicy( policy );
}
int CircleBar::heightForWidth( int width ) const
{
  return width;
}
QSize CircleBar::sizeHint() const
{
  return QSize( 100, 100 );
}
int CircleBar::value() const
{
  return m_value;
}
void CircleBar::setValue( int value )
{
  if( value < 0 )
    value = 0;
  
  if( value > 100 )
    value = 100;
    
  if( m_value == value )
    return;
    
  m_value = value;
  update();
  emit valueChanged( m_value );
}
void CircleBar::paintEvent( QPaintEvent *event )
{
  int radius = width()/2;
  double factor = m_value/100.0;
  
  QPainter p( this );
  p.setPen( Qt::black );
  p.drawEllipse( 0, 0, width()-1, width()-1 );
  p.setBrush( Qt::black );
  p.drawEllipse( int(radius*(1.0-factor)), int(radius*(1.0-factor)), int((width()-1)*factor)+1, int((width()-1)*factor)+1 );
}
void CircleBar::wheelEvent( QWheelEvent *event )
{
  event->accept();
  setValue( value() + event->delta()/20 );
}

Foundations of Qt Development\Chapter06\designerplugin\circlebar.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 CIRCLEBAR_H
#define CIRCLEBAR_H
#include <QWidget>
#include <QtDesigner>
class QDESIGNER_WIDGET_EXPORT CircleBar : public QWidget
{
  Q_OBJECT
public:
  CircleBar( QWidget *parent = 0 );
  CircleBar( int value = 0, QWidget *parent = 0 );
  
  int value() const;
  
  int heightForWidth( int ) const;
  QSize sizeHint() const;  
public slots:
  void setValue( int );
  
signals:
  void valueChanged( int );
  
protected:
  void paintEvent( QPaintEvent* );
  void wheelEvent( QWheelEvent* );
  
private:
  int m_value;
};
#endif // CIRCLEBAR_H

Foundations of Qt Development\Chapter06\designerplugin\circlebarplugin.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 <QtPlugin>
#include <QExtensionManager>
#include <QDesignerFormEditorInterface>
#include <QTimer>
#include "circlebar.h"
#include "circlebarplugin.h"
CircleBarPlugin::CircleBarPlugin( QObject *parent )
{
    m_initialized = false;
}
bool CircleBarPlugin::isInitialized() const
{
    return m_initialized;
}
void CircleBarPlugin::initialize( QDesignerFormEditorInterface *core )
{
    if( m_initialized )
        return;
    m_initialized = true;
}
bool CircleBarPlugin::isContainer() const
{
    return false;
}
QIcon CircleBarPlugin::icon() const
{
    return QIcon();
}
QString CircleBarPlugin::toolTip() const
{
    return "";
}
QString CircleBarPlugin::whatsThis() const
{
    return "";
}
QString CircleBarPlugin::codeTemplate() const
{
    return "";
}
QString CircleBarPlugin::includeFile() const
{
    return "circlebar.h";
}
QString CircleBarPlugin::name() const
{
    return "CircleBar";
}
QString CircleBarPlugin::domXml() const
{
    return "<widget class=\"CircleBar\" name=\"circleBar\">\n"
           "</widget>\n";
}
QString CircleBarPlugin::group() const
{
    return "Book Widgets";
}
QWidget *CircleBarPlugin::createWidget( QWidget *parent )
{
    return new CircleBar( parent );
}
Q_EXPORT_PLUGIN2( circleBarPlugin, CircleBarPlugin )

Foundations of Qt Development\Chapter06\designerplugin\circlebarplugin.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 CIRCLEBARPLUGIN_H
#define CIRCLEBARPLUGIN_H
#include <QDesignerCustomWidgetInterface>
class QExtensionManager;
class CircleBarPlugin : public QObject, public QDesignerCustomWidgetInterface
{
    Q_OBJECT
    Q_INTERFACES(QDesignerCustomWidgetInterface)
public:
    CircleBarPlugin( QObject *parent = 0 );
    bool isContainer() const;
    bool isInitialized() const;
    QIcon icon() const;
    QString codeTemplate() const;
    QString domXml() const;
    QString group() const;
    QString includeFile() const;
    QString name() const;
    QString toolTip() const;
    QString whatsThis() const;
    QWidget *createWidget( QWidget *parent );
    void initialize( QDesignerFormEditorInterface *core );
private:
    bool m_initialized;
};
#endif /* CIRCLEBARPLUGIN_H */


Model view controller

  
/****************************************************************************
**
** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the documentation of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial Usage
** Licensees holding valid Qt Commercial licenses may use this file in
** accordance with the Qt Commercial License Agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Nokia.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Nokia gives you certain additional
** rights.  These rights are described in the Nokia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3.0 as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU General Public License version 3.0 requirements will be
** met: http://www.gnu.org/copyleft/gpl.html.
**
** If you have questions regarding the use of this file, please contact
** Nokia at qt-info@nokia.com.
** $QT_END_LICENSE$
**
****************************************************************************/
#ifndef VIEW_H
#define VIEW_H
#include <QAbstractItemView>
#include <QItemSelection>
#include <QItemSelectionModel>
#include <QModelIndex>
#include <QRect>
#include <QSize>
#include <QWidget>
class LinearView : public QAbstractItemView
{
    Q_OBJECT
public:
    LinearView(QWidget *parent = 0);
    QRect itemViewportRect(const QModelIndex &index) const;
    void ensureVisible(const QModelIndex &index);
    QModelIndex itemAt(int x, int y) const;
protected slots:
    /*void dataChanged(const QModelIndex &topLeft, const QModelIndex
    &bottomRight);*/
    void rowsInserted(const QModelIndex &parent, int start, int end);
    void rowsRemoved(const QModelIndex &parent, int start, int end);
    /*void selectionChanged(const QItemSelection &deselected, const QItemSelection &selected);
    void verticalScrollbarAction(int action);
    void horizontalScrollbarAction(int action);*/
protected:
    void setSelection(const QRect&, QItemSelectionModel::SelectionFlags command);
    QRect selectionViewportRect(const QItemSelection &selection) const;
    QRect itemRect(const QModelIndex &item) const;
    bool isIndexHidden(const QModelIndex &index) const;
    int horizontalOffset() const;
    int verticalOffset() const;
    QModelIndex moveCursor(QAbstractItemView::CursorAction cursorAction,
                           Qt::KeyboardModifiers modifiers);
    void paintEvent(QPaintEvent *event);
    void resizeEvent(QResizeEvent *event);
    QSize sizeHint() const;
private:
    int rows(const QModelIndex &index = QModelIndex()) const;
    void updateGeometries();
};
#endif



/*!
    view.cpp
    Provides a view to represent a one-dimensional sequence of integers
    obtained from a list model as a series of rows.
*/
#include <QAbstractItemModel>
#include <QBrush>
#include <QItemSelection>
#include <QPainter>
#include <QPaintEvent>
#include <QPen>
#include <QPoint>
#include <QResizeEvent>
#include <QScrollBar>
#include <QSizePolicy>
#include "view.h"
LinearView::LinearView(QWidget *parent)
    : QAbstractItemView(parent)
{
    setSizePolicy(QSizePolicy::Preferred, QSizePolicy::Fixed);
}
/*!
    Returns the position of the item in viewport coordinates.
*/
QRect LinearView::itemViewportRect(const QModelIndex &index) const
{
    QRect rect = itemRect(index);
    QRect result(rect.left() - horizontalScrollBar()->value(),
                 rect.top() - verticalScrollBar()->value(),
                 rect.width(), viewport()->height());
    return result;
}
/*!
    Returns the rectangle of the item at position \a index in the
    model. The rectangle is in contents coordinates.
*/
QRect LinearView::itemRect(const QModelIndex &index) const
{
    if (!index.isValid())
        return QRect();
    else
        return QRect(index.row(), 0, 1, 1);
}

void LinearView::ensureVisible(const QModelIndex &index)
{
    QRect area = viewport()->rect();
    QRect rect = itemViewportRect(index);
    if (rect.left() < area.left())
        horizontalScrollBar()->setValue(
            horizontalScrollBar()->value() - rect.left());
    else if (rect.right() > area.right())
        horizontalScrollBar()->setValue(
            horizontalScrollBar()->value() + rect.left() - area.width());
}
/*!
    Returns the item that covers the coordinate given in the view.
*/
QModelIndex LinearView::itemAt(int x, int /* y */) const
{
    int row = x + horizontalScrollBar()->value();
    return model()->index(row, 0, QModelIndex());
}
//void LinearView::dataChanged(const QModelIndex &/* topLeft */,
//    const QModelIndex &/* bottomRight */)
//{
//    updateGeometries();
//    if (isVisible())
//        repaint();
//}
void LinearView::rowsInserted(const QModelIndex &/* parent */, int /* start */,
    int /* end */)
{
    updateGeometries();
    if (isVisible())
        repaint();
}
void LinearView::rowsRemoved(const QModelIndex &/* parent */, int /* start */,
    int /* end */)
{
    updateGeometries();
    if (isVisible())
        repaint();
}
/*
void LinearView::verticalScrollbarAction(int action)
{
}
void LinearView::horizontalScrollbarAction(int action)
{
}
*/
/*!
    Select the items in the model that lie within the rectangle specified by
    \a rect, using the selection \a command.
*/
void LinearView::setSelection(const QRect &rect, QItemSelectionModel::SelectionFlags command)
{
    QModelIndex leftIndex = itemAt(rect.left(), 0);
    QModelIndex rightIndex = itemAt(rect.right(), 0);
    QItemSelection selection(leftIndex, rightIndex);
    selectionModel()->select(selection, command);
}
QModelIndex LinearView::moveCursor(QAbstractItemView::CursorAction cursorAction,
                                   Qt::KeyboardModifiers)
{
    QModelIndex current = currentIndex();
    switch (cursorAction) {
    case MoveLeft:{
        if (current.row() > 0)
            return model()->index(current.row() - 1, 0, QModelIndex());
        else
            return model()->index(0, 0, QModelIndex());
        break;}
    case MoveRight:{
        if (current.row() < rows(current) - 1)
            return model()->index(current.row() + 1, 0, QModelIndex());
        else
            return model()->index(rows(current) - 1, 0,QModelIndex());
        break;}
    case MoveUp:
        return current;
    case MoveDown:
        return current;
    case MovePageUp:
        return current;
    case MovePageDown:
        return current;
    case MoveHome:
        return model()->index(0, 0, QModelIndex());
    case MoveEnd:
        return model()->index(rows(current) - 1, 0, QModelIndex());
    default:
        return current;
    }
}
int LinearView::horizontalOffset() const
{
    return horizontalScrollBar()->value();
}
int LinearView::verticalOffset() const
{
    return verticalScrollBar()->value();
}
/*!
    Returns a rectangle corresponding to the selection in viewport cooridinates.
*/
QRect LinearView::selectionViewportRect(const QItemSelection &selection) const
{
    int ranges = selection.count();
    if (ranges == 0)
        return QRect();
    // Note that we use the top and bottom functions of the selection range
    // since the data is stored in rows.
    int firstRow = selection.at(0).top();
    int lastRow = selection.at(0).top();
    for (int i = 0; i < ranges; ++i) {
        firstRow = qMin(firstRow, selection.at(i).top());
        lastRow = qMax(lastRow, selection.at(i).bottom());
    }
    QModelIndex firstItem = model()->index(qMin(firstRow, lastRow), 0,
        QModelIndex());
    QModelIndex lastItem = model()->index(qMax(firstRow, lastRow), 0,
        QModelIndex());
    QRect firstRect = itemViewportRect(firstItem);
    QRect lastRect = itemViewportRect(lastItem);
    return QRect(firstRect.left(), firstRect.top(),
        lastRect.right() - firstRect.left(), firstRect.height());
}
void LinearView::paintEvent(QPaintEvent *event)
{
    QPainter painter(viewport());
    QRect updateRect = event->rect();
    QBrush background(Qt::black);
    QPen foreground(Qt::white);
    painter.fillRect(updateRect, background);
    painter.setPen(foreground);
    QModelIndex firstItem = itemAt(updateRect.left(), updateRect.top());
    if (!firstItem.isValid())
        firstItem = model()->index(0, 0, QModelIndex());
    QModelIndex lastItem = itemAt(updateRect.right(), updateRect.bottom());
    if (!lastItem.isValid())
        lastItem = model()->index(rows() - 1, 0, QModelIndex());
    int x = updateRect.left();
    //int top = updateRect.top();
    //int bottom = updateRect.bottom();
    int row = firstItem.row();
    QModelIndex index = model()->index(row, 0, QModelIndex());
    int value = model()->data(index, Qt::DisplayRole).toInt();
    int midPoint = viewport()->height()/2;
    int y2 = midPoint - int(value * midPoint/255.0);
    while (row <= lastItem.row()) {
        QModelIndex index = model()->index(row, 0, QModelIndex());
        int value = model()->data(index, Qt::DisplayRole).toInt();
        int y1 = y2;
        y2 = midPoint - int(value * midPoint/255.0);
        painter.drawLine(x-1, y1, x, y2);
        ++row; ++x;
    }
}
void LinearView::resizeEvent(QResizeEvent * /* event */)
{
    updateGeometries();
}
void LinearView::updateGeometries()
{
    if (viewport()->width() < rows()) {
        horizontalScrollBar()->setPageStep(viewport()->width());
        horizontalScrollBar()->setRange(0, rows() - viewport()->width() - 1);
    }
}
QSize LinearView::sizeHint() const
{
    return QSize(rows(), 200);
}
int LinearView::rows(const QModelIndex &index) const
{
    return model()->rowCount(model()->parent(index));
}
bool LinearView::isIndexHidden(const QModelIndex &index) const
{
    return false;
}



#ifndef MODEL_H
#define MODEL_H
#include <QAbstractListModel>
#include <QObject>
#include <qvector.h>
class LinearModel : public QAbstractListModel
{
    Q_OBJECT
public:
    LinearModel(QObject *parent = 0)
        : QAbstractListModel(parent) {}
    int rowCount(const QModelIndex &parent = QModelIndex()) const;
    QModelIndex index(int row, int column = 0, const QModelIndex &parent = QModelIndex()) const;
    QVariant data(const QModelIndex &index, int role) const;
    Qt::ItemFlags flags(const QModelIndex &index) const;
    bool setData(const QModelIndex &index, const QVariant &value,
                 int role = Qt::EditRole);
    bool insertRows(int position, int rows, const QModelIndex &index = QModelIndex());
    bool removeRows(int position, int rows, const QModelIndex &index = QModelIndex());
private:
    QVector<int> values;
};
#endif



/*
  model.cpp
  A simple model that uses a QVector as its data source.
*/
#include "model.h"
/*!
    Returns the number of items in the string list as the number of rows
    in the model.
*/
int LinearModel::rowCount(const QModelIndex &parent) const
{
    Q_USING(parent);
    return values.count();
}
/*
    Returns an appropriate value for the requested data.
    If the view requests an invalid index, an invalid variant is returned.
    If a header is requested then we just return the column or row number,
    depending on the orientation of the header.
    Any valid index that corresponds to a string in the list causes that
    string to be returned.
*/
/*!
    Returns a model index for other component to use when referencing the
    item specified by the given row, column, and type. The parent index
    is ignored.
*/
QModelIndex LinearModel::index(int row, int column, const QModelIndex &parent) const
{
    if (parent == QModelIndex() && row >= 0 && row < rowCount()
        && column == 0)
        return createIndex(row, column, 0);
    else
        return QModelIndex();
}
QVariant LinearModel::data(const QModelIndex &index, int role) const
{
    Q_UNUSED(role);
    if (!index.isValid())
        return QVariant();
    return values.at(index.row());
}
/*!
    Returns Qt::ItemIsEditable so that all items in the vector can be edited.
*/
Qt::ItemFlags LinearModel::flags(const QModelIndex &index) const
{
    // all items in the model are editable
    return QAbstractListModel::flags(index) | Qt::ItemIsEditable;
}
/*!
    Changes an item in the string list, but only if the following conditions
    are met:
    * The index supplied is valid.
    * The index corresponds to an item to be shown in a view.
    * The role associated with editing text is specified.
    The dataChanged() signal is emitted if the item is changed.
*/
bool LinearModel::setData(const QModelIndex &index,
                          const QVariant &value, int role)
{
    if (!index.isValid() || role != Qt::EditRole)
        return false;
    values.replace(index.row(), value.toInt());
    emit dataChanged(index, index);
    return true;
}
/*!
    Inserts a number of rows into the model at the specified position.
*/
bool LinearModel::insertRows(int position, int rows, const QModelIndex &parent)
{
    beginInsertRows(parent, position, position + rows - 1);
    values.insert(position, rows, 0);
    endInsertRows();
    return true;
}
/*!
    Removes a number of rows from the model at the specified position.
*/
bool LinearModel::removeRows(int position, int rows, const QModelIndex &parent)
{
    beginRemoveRows(QModelIndex(), position, position+rows-1);
    values.remove(position, rows);
    endRemoveRows();
    return true;
}





#ifndef WINDOW_H
#define WINDOW_H
#include <QMainWindow>
#include <QString>
#include <QWidget>
#include "model.h"
#include "view.h"
class MainWindow : public QMainWindow
{
    Q_OBJECT
public:
    MainWindow::MainWindow(QWidget *parent = 0);
public slots:
    void selectOpenFile();
private:
    void setupModelView();
    void openFile(const QString &fileName);
    LinearModel *model;
    LinearView *view;
};
#endif



#include <QAction>
#include <QDataStream>
#include <QMenu>
#include <QMenuBar>
#include <QFile>
#include <QFileDialog>
#include <QListView>
#include "window.h"
MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
{
    setWindowTitle("Model/View example");
    setupModelView();
    QAction *openAction = new QAction(tr("&Open"), this);
    QAction *quitAction = new QAction(tr("E&xit"), this);
    QMenu *fileMenu = new QMenu(tr("&File"), this);
    fileMenu->addAction(openAction);
    fileMenu->addAction(quitAction);
    menuBar()->addMenu(fileMenu);
    connect(openAction, SIGNAL(triggered()), this, SLOT(selectOpenFile()));
    connect(quitAction, SIGNAL(triggered()), this, SLOT(close()));
    setCentralWidget(view);
}
void MainWindow::setupModelView()
{
    model = new LinearModel(this);
    view = new LinearView(this);
    view->setModel(model);
}
void MainWindow::selectOpenFile()
{
    QString fileName = QFileDialog::getOpenFileName(this,
        tr("Select a file to open"), "", tr("Sound files (*.wav)"));
    
    if (!fileName.isEmpty())
        openFile(fileName);
}
void MainWindow::openFile(const QString &fileName)
{
    QFile file(fileName);
    int length = file.size();
    if (file.open(QFile::ReadOnly)) {
        model->removeRows(0, model->rowCount());
        int rows = (length - 0x2c)/2;
        model->insertRows(0, rows);
        // Perform some dodgy tricks to extract the data from the file.
        QDataStream stream(&file);
        stream.setByteOrder(QDataStream::LittleEndian);
        Q_INT16 left;
        Q_INT16 right;
        for (int row = 0; row < rows; ++row) {
            QModelIndex index = model->index(row);
            stream >> left >> right;
            model->setData(index, int(left / 256));
        }
    }
}



/*
    main.cpp
    An example of a main window application that used a subclassed model
    and view to display data from sound files.
*/
#include <QApplication>
#include "model.h"
#include "view.h"
#include "window.h"
/*!
    The main function for the linear model example. This creates and
    populates a model with long integers then displays the contents of the
    model using a QListView widget.
*/
int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    MainWindow *window = new MainWindow;
    window->show();
    return app.exec();
}