modelmenu.cpp Example File

/****************************************************************************
**
** Copyright (C) 2016 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of the examples of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:BSD$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company. For licensing terms
** and conditions see https://www.qt.io/terms-conditions. For further
** information use the contact form at https://www.qt.io/contact-us.
**
** BSD License Usage
** Alternatively, you may use this file under the terms of the BSD license
** as follows:
**
** "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 The Qt Company Ltd 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."
**
** $QT_END_LICENSE$
**
****************************************************************************/
#include "modelmenu.h"
#include <QtCore/QAbstractItemModel>
#include <qdebug.h>
ModelMenu::ModelMenu(QWidget * parent)
    : QMenu(parent)
    , m_maxRows(7)
    , m_firstSeparator(-1)
    , m_maxWidth(-1)
    , m_hoverRole(0)
    , m_separatorRole(0)
    , m_model(0)
{
    connect(this, SIGNAL(aboutToShow()), this, SLOT(aboutToShow()));
}
bool ModelMenu::prePopulated()
{
    return false;
}
void ModelMenu::postPopulated()
{
}
void ModelMenu::setModel(QAbstractItemModel *model)
{
    m_model = model;
}
QAbstractItemModel *ModelMenu::model() const
{
    return m_model;
}
void ModelMenu::setMaxRows(int max)
{
    m_maxRows = max;
}
int ModelMenu::maxRows() const
{
    return m_maxRows;
}
void ModelMenu::setFirstSeparator(int offset)
{
    m_firstSeparator = offset;
}
int ModelMenu::firstSeparator() const
{
    return m_firstSeparator;
}
void ModelMenu::setRootIndex(const QModelIndex &index)
{
    m_root = index;
}
QModelIndex ModelMenu::rootIndex() const
{
    return m_root;
}
void ModelMenu::setHoverRole(int role)
{
    m_hoverRole = role;
}
int ModelMenu::hoverRole() const
{
    return m_hoverRole;
}
void ModelMenu::setSeparatorRole(int role)
{
    m_separatorRole = role;
}
int ModelMenu::separatorRole() const
{
    return m_separatorRole;
}
Q_DECLARE_METATYPE(QModelIndex)
void ModelMenu::aboutToShow()
{
    if (QMenu *menu = qobject_cast<QMenu*>(sender())) {
        QVariant v = menu->menuAction()->data();
        if (v.canConvert<QModelIndex>()) {
            QModelIndex idx = qvariant_cast<QModelIndex>(v);
            createMenu(idx, -1, menu, menu);
            disconnect(menu, SIGNAL(aboutToShow()), this, SLOT(aboutToShow()));
            return;
        }
    }
    clear();
    if (prePopulated())
        addSeparator();
    int max = m_maxRows;
    if (max != -1)
        max += m_firstSeparator;
    createMenu(m_root, max, this, this);
    postPopulated();
}
void ModelMenu::createMenu(const QModelIndex &parent, int max, QMenu *parentMenu, QMenu *menu)
{
    if (!menu) {
        QString title = parent.data().toString();
        menu = new QMenu(title, this);
        QIcon icon = qvariant_cast<QIcon>(parent.data(Qt::DecorationRole));
        menu->setIcon(icon);
        parentMenu->addMenu(menu);
        QVariant v;
        v.setValue(parent);
        menu->menuAction()->setData(v);
        connect(menu, SIGNAL(aboutToShow()), this, SLOT(aboutToShow()));
        return;
    }
    int end = m_model->rowCount(parent);
    if (max != -1)
        end = qMin(max, end);
    connect(menu, SIGNAL(triggered(QAction*)), this, SLOT(triggered(QAction*)));
    connect(menu, SIGNAL(hovered(QAction*)), this, SLOT(hovered(QAction*)));
    for (int i = 0; i < end; ++i) {
        QModelIndex idx = m_model->index(i, 0, parent);
        if (m_model->hasChildren(idx)) {
            createMenu(idx, -1, menu);
        } else {
            if (m_separatorRole != 0
                && idx.data(m_separatorRole).toBool())
                addSeparator();
            else
                menu->addAction(makeAction(idx));
        }
        if (menu == this && i == m_firstSeparator - 1)
            addSeparator();
    }
}
QAction *ModelMenu::makeAction(const QModelIndex &index)
{
    QIcon icon = qvariant_cast<QIcon>(index.data(Qt::DecorationRole));
    QAction *action = makeAction(icon, index.data().toString(), this);
    QVariant v;
    v.setValue(index);
    action->setData(v);
    return action;
}
QAction *ModelMenu::makeAction(const QIcon &icon, const QString &text, QObject *parent)
{
    QFontMetrics fm(font());
    if (-1 == m_maxWidth)
        m_maxWidth = fm.width(QLatin1Char('m')) * 30;
    QString smallText = fm.elidedText(text, Qt::ElideMiddle, m_maxWidth);
    return new QAction(icon, smallText, parent);
}
void ModelMenu::triggered(QAction *action)
{
    QVariant v = action->data();
    if (v.canConvert<QModelIndex>()) {
        QModelIndex idx = qvariant_cast<QModelIndex>(v);
        emit activated(idx);
    }
}
void ModelMenu::hovered(QAction *action)
{
    QVariant v = action->data();
    if (v.canConvert<QModelIndex>()) {
        QModelIndex idx = qvariant_cast<QModelIndex>(v);
        QString hoveredString = idx.data(m_hoverRole).toString();
        if (!hoveredString.isEmpty())
            emit hovered(hoveredString);
    }
}