A simple model that uses a QStringList as its data source
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/****************************************************************************
**
** 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 an example program for Qt.
** EDITIONS: NOLIMITS
**
****************************************************************************/
#ifndef MODEL_H
#define MODEL_H
#include <QAbstractListModel>
#include <QObject>
#include <QStringList>
class StringListModel : public QAbstractListModel
{
Q_OBJECT
public:
StringListModel(const QStringList &strings, QObject *parent = 0)
: QAbstractListModel(parent), stringList(strings) {}
int rowCount(const QModelIndex &parent = QModelIndex()) const;
QVariant data(const QModelIndex &index, int role) const;
QVariant headerData(int section, Qt::Orientation orientation,
int role = Qt::DisplayRole) 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:
QStringList stringList;
};
#endif
/*
model.cpp
A simple model that uses a QStringList 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 StringListModel::rowCount(const QModelIndex &parent) const
{
return stringList.count();
}
/*!
Returns an appropriate value for the requested data.
If the view requests an invalid index, an invalid variant is returned.
Any valid index that corresponds to a string in the list causes that
string to be returned.
*/
QVariant StringListModel::data(const QModelIndex &index, int role) const
{
if (!index.isValid())
return QVariant();
if (index.row() >= stringList.size())
return QVariant();
if (role == Qt::DisplayRole)
return stringList.at(index.row());
else
return QVariant();
}
/*!
Returns the appropriate header string depending on the orientation of
the header and the section. If anything other than the display role is
requested, we return an invalid variant.
*/
QVariant StringListModel::headerData(int section, Qt::Orientation orientation,
int role) const
{
if (role != Qt::DisplayRole)
return QVariant();
if (orientation == Qt::Horizontal)
return QString("Column %1").arg(section);
else
return QString("Row %1").arg(section);
}
/*!
Returns an appropriate value for the item's flags. Valid items are
enabled, selectable, and editable.
*/
Qt::ItemFlags StringListModel::flags(const QModelIndex &index) const
{
if (!index.isValid())
return Qt::ItemIsEnabled;
return QAbstractItemModel::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 StringListModel::setData(const QModelIndex &index,
const QVariant &value, int role)
{
if (index.isValid() && role == Qt::EditRole) {
stringList.replace(index.row(), value.toString());
emit dataChanged(index, index);
return true;
}
return false;
}
/*!
Inserts a number of rows into the model at the specified position.
*/
bool StringListModel::insertRows(int position, int rows, const QModelIndex &parent)
{
beginInsertRows(QModelIndex(), position, position+rows-1);
for (int row = 0; row < rows; ++row) {
stringList.insert(position, "");
}
endInsertRows();
return true;
}
/*!
Removes a number of rows from the model at the specified position.
*/
bool StringListModel::removeRows(int position, int rows, const QModelIndex &parent)
{
beginRemoveRows(QModelIndex(), position, position+rows-1);
for (int row = 0; row < rows; ++row) {
stringList.removeAt(position);
}
endRemoveRows();
return true;
}
#ifndef WINDOW_H
#define WINDOW_H
#include <QMainWindow>
#include <QModelIndex>
class QAction;
class QListView;
class StringListModel;
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
MainWindow();
public slots:
void insertItem();
void removeItem();
void sortAscending();
void sortDescending();
void updateMenus(const QModelIndex ¤t);
private:
QAction *insertAction;
QAction *removeAction;
QListView *listView;
StringListModel *model;
};
#endif
#include <QtGui>
#include "mainwindow.h"
#include "model.h"
MainWindow::MainWindow()
{
QMenu *fileMenu = new QMenu(tr("&File"));
QAction *quitAction = fileMenu->addAction(tr("E&xit"));
quitAction->setShortcut(tr("Ctrl+Q"));
QMenu *itemsMenu = new QMenu(tr("&Items"));
insertAction = itemsMenu->addAction(tr("&Insert Item"));
removeAction = itemsMenu->addAction(tr("&Remove Item"));
QAction *ascendingAction = itemsMenu->addAction(tr("Sort in &Ascending Order"));
QAction *descendingAction = itemsMenu->addAction(tr("Sort in &Descending Order"));
menuBar()->addMenu(fileMenu);
menuBar()->addMenu(itemsMenu);
QStringList strings;
strings << tr("Oak") << tr("Fir") << tr("Pine") << tr("Birch")
<< tr("Hazel") << tr("Redwood") << tr("Sycamore") << tr("Chestnut");
model = new StringListModel(strings, this);
/* For convenient quoting:
QListView *listView = new QListView(this);
*/
listView = new QListView(this);
listView->setModel(model);
listView->setSelectionMode(QAbstractItemView::SingleSelection);
connect(quitAction, SIGNAL(triggered()), this, SLOT(close()));
connect(ascendingAction, SIGNAL(triggered()), this, SLOT(sortAscending()));
connect(descendingAction, SIGNAL(triggered()), this, SLOT(sortDescending()));
connect(insertAction, SIGNAL(triggered()), this, SLOT(insertItem()));
connect(removeAction, SIGNAL(triggered()), this, SLOT(removeItem()));
connect(listView->selectionModel(),
SIGNAL(currentChanged(const QModelIndex &, const QModelIndex &)),
this, SLOT(updateMenus(const QModelIndex &)));
updateMenus(listView->selectionModel()->currentIndex());
setCentralWidget(listView);
setWindowTitle(tr("List View"));
}
void MainWindow::sortAscending()
{
model->sort(0, Qt::AscendingOrder);
}
void MainWindow::sortDescending()
{
model->sort(0, Qt::DescendingOrder);
}
void MainWindow::insertItem()
{
QModelIndex currentIndex = listView->currentIndex();
if (!currentIndex.isValid())
return;
QString itemText = QInputDialog::getText(this, tr("Insert Item"),
tr("Input text for the new item:"));
if (itemText.isNull())
return;
if (model->insertRow(currentIndex.row(), QModelIndex())) {
QModelIndex newIndex = model->index(currentIndex.row(), 0, QModelIndex());
model->setData(newIndex, itemText, Qt::EditRole);
QString toolTipText = tr("Tooltip:") + itemText;
QString statusTipText = tr("Status tip:") + itemText;
QString whatsThisText = tr("What's This?:") + itemText;
model->setData(newIndex, toolTipText, Qt::ToolTipRole);
model->setData(newIndex, toolTipText, Qt::StatusTipRole);
model->setData(newIndex, whatsThisText, Qt::WhatsThisRole);
}
}
void MainWindow::removeItem()
{
QModelIndex currentIndex = listView->currentIndex();
if (!currentIndex.isValid())
return;
model->removeRow(currentIndex.row(), QModelIndex());
}
void MainWindow::updateMenus(const QModelIndex ¤t)
{
insertAction->setEnabled(current.isValid());
removeAction->setEnabled(current.isValid());
}
#include <QtGui>
#include "mainwindow.h"
int main(int argc, char *argv[])
{
QApplication app(argc, argv);
MainWindow *window = new MainWindow;
window->show();
return app.exec();
}
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