C++/Qt/QAbstractListModel

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extends QAbstractListModel to create file list model

  
/****************************************************************************
**
** 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 examples 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 FILELISTMODEL_H
#define FILELISTMODEL_H
#include <QAbstractListModel>
#include <QList>
#include <QStringList>

class FileListModel : public QAbstractListModel
{
    Q_OBJECT
public:
    FileListModel(QObject *parent = 0);
    int rowCount(const QModelIndex &parent = QModelIndex()) const;
    QVariant data(const QModelIndex &index, int role = Qt::DisplayRole) const;
signals:
    void numberPopulated(int number);
public slots:
    void setDirPath(const QString &path);
protected:
    bool canFetchMore(const QModelIndex &parent) const;
    void fetchMore(const QModelIndex &parent);
private:
    QStringList fileList;
    int fileCount;
};

#endif


/****************************************************************************
**
** 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 examples 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.
** $QT_END_LICENSE$
**
****************************************************************************/
#include "filelistmodel.h"
#include <QApplication>
#include <QPalette>
#include <QBrush>
#include <QDir>
FileListModel::FileListModel(QObject *parent)
    : QAbstractListModel(parent)
{
}

int FileListModel::rowCount(const QModelIndex & /* parent */) const
{
    return fileCount;
}
QVariant FileListModel::data(const QModelIndex &index, int role) const
{
    if (!index.isValid())
        return QVariant();
    
    if (index.row() >= fileList.size() || index.row() < 0)
        return QVariant();
    
    if (role == Qt::DisplayRole)
        return fileList.at(index.row());
    else if (role == Qt::BackgroundRole) {
        int batch = (index.row() / 100) % 2;
        if (batch == 0)
            return qApp->palette().base();
        else
            return qApp->palette().alternateBase();
    }
    return QVariant();
}

bool FileListModel::canFetchMore(const QModelIndex & /* index */) const
{
    if (fileCount < fileList.size())
        return true;
    else
        return false;
}

void FileListModel::fetchMore(const QModelIndex & /* index */)
{
    int remainder = fileList.size() - fileCount;
    int itemsToFetch = qMin(100, remainder);
    beginInsertRows(QModelIndex(), fileCount, fileCount+itemsToFetch);
    
    fileCount += itemsToFetch;
    endInsertRows();
    emit numberPopulated(itemsToFetch);
}

void FileListModel::setDirPath(const QString &path)
{
    QDir dir(path);
    fileList = dir.entryList();
    fileCount = 0;
    reset();
}



#ifndef WINDOW_H
#define WINDOW_H
#include <QWidget>
QT_BEGIN_NAMESPACE
class QTextBrowser;
QT_END_NAMESPACE
class Window : public QWidget
{
    Q_OBJECT
public:
    Window(QWidget *parent = 0);
public slots:
    void updateLog(int number);
private:
    QTextBrowser *logViewer;
};
#endif


#include <QtGui>
#include "filelistmodel.h"
#include "window.h"
Window::Window(QWidget *parent)
    : QWidget(parent)
{
    FileListModel *model = new FileListModel(this);
    model->setDirPath(QLibraryInfo::location(QLibraryInfo::PrefixPath));
    QLabel *label = new QLabel(tr("&Directory:"));
    QLineEdit *lineEdit = new QLineEdit;
    label->setBuddy(lineEdit);
    QListView *view = new QListView;
    view->setModel(model);
    logViewer = new QTextBrowser;
    logViewer->setSizePolicy(QSizePolicy(QSizePolicy::Preferred, QSizePolicy::Preferred));
    connect(lineEdit, SIGNAL(textChanged(const QString &)),
            model, SLOT(setDirPath(const QString &)));
    connect(lineEdit, SIGNAL(textChanged(const QString &)),
            logViewer, SLOT(clear()));
    connect(model, SIGNAL(numberPopulated(int)),
            this, SLOT(updateLog(int)));
    
    QGridLayout *layout = new QGridLayout;
    layout->addWidget(label, 0, 0);
    layout->addWidget(lineEdit, 0, 1);
    layout->addWidget(view, 1, 0, 1, 2);
    layout->addWidget(logViewer, 2, 0, 1, 2);
    setLayout(layout);
    setWindowTitle(tr("Fetch More Example"));
}
void Window::updateLog(int number)
{
    logViewer->append(tr("%1 items added.").arg(number));
}


#include <QApplication>
#include "window.h"
int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    Window window;
    window.show();
    return app.exec();
}


persistent indexes

  
/****************************************************************************
**
** 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 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 <qdebug.h>
#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.
    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.
*/
QVariant StringListModel::data(const QModelIndex &index, int role) const
{
    if (!index.isValid())
        return QVariant();
    if (index.row() < 0 || 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(parent, 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(parent, position, position + rows - 1);
    for (int row = 0; row < rows; ++row) {
        stringList.removeAt(position);
    }
    endRemoveRows();
    return true;
}


#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
#include <QModelIndex>
class QAbstractItemModel;
class QAction;
class QItemSelectionModel;
class MainWindow : public QMainWindow
{
    Q_OBJECT
public:
    MainWindow(QWidget *parent = 0);
private slots:
    void insertItem();
    void removeItem();
    void updateMenus(const QModelIndex &currentIndex);
private:
    QAbstractItemModel *model;
    QAction *insertAction;
    QAction *removeAction;
    QItemSelectionModel *selectionModel;
};
#endif


#include <QtGui>
#include "mainwindow.h"
#include "model.h"
/*!
    The main window constructor creates and populates a model with values
    from a string list then displays the contents of the model using a
    QListView widget.
*/
MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
{
    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"));
    menuBar()->addMenu(fileMenu);
    menuBar()->addMenu(itemsMenu);
    QStringList numbers;
    numbers << tr("One") << tr("Two") << tr("Three") << tr("Four") << tr("Five")
            << tr("Six") << tr("Seven") << tr("Eight") << tr("Nine") << tr("Ten");
    model = new StringListModel(numbers);
    QListView *view = new QListView(this);
    view->setModel(model);
    selectionModel = view->selectionModel();
    connect(quitAction, SIGNAL(triggered()), qApp, SLOT(quit()));
    connect(insertAction, SIGNAL(triggered()), this, SLOT(insertItem()));
    connect(removeAction, SIGNAL(triggered()), this, SLOT(removeItem()));
    connect(selectionModel,
            SIGNAL(currentChanged(const QModelIndex &, const QModelIndex &)),
            this, SLOT(updateMenus(const QModelIndex &)));
    
    setCentralWidget(view);
    setWindowTitle("View onto a string list model");
}
void MainWindow::insertItem()
{
    if (!selectionModel->currentIndex().isValid())
        return;
    QString itemText = QInputDialog::getText(this, tr("Insert Item"),
        tr("Input text for the new item:"));
    if (itemText.isNull())
        return;
    int row = selectionModel->currentIndex().row();
    if (model->insertRows(row, 1))
        model->setData(model->index(row, 0), itemText, Qt::EditRole);
}
void MainWindow::removeItem()
{
    if (!selectionModel->currentIndex().isValid())
        return;
    int row = selectionModel->currentIndex().row();
    model->removeRows(row, 1);
}
void MainWindow::updateMenus(const QModelIndex &currentIndex)
{
    insertAction->setEnabled(currentIndex.isValid());
    removeAction->setEnabled(currentIndex.isValid());
}


#include <QApplication>
#include "mainwindow.h"
int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    MainWindow *window = new MainWindow;
    window->show();
    return app.exec();
}


string list model example

  
/****************************************************************************
**
** 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 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;
 
}



/*!
    The main function for the string list model example. This creates and
    populates a model with values from a string list then displays the
    contents of the model using a QListView widget.
*/
#include <QAbstractItemModel>
#include <QApplication>
#include <QListView>
#include "model.h"

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
// Unindented for quoting purposes:
QStringList numbers;
numbers << "One" << "Two" << "Three" << "Four" << "Five";
QAbstractItemModel *model = new StringListModel(numbers);
   
QListView *view = new QListView;
view->setWindowTitle("View onto a string list model");
view->setModel(model);
 
    model->insertRows(5, 7, QModelIndex());
    for (int row = 5; row < 12; ++row) {
        QModelIndex index = model->index(row, 0, QModelIndex());
        model->setData(index, QString::number(row+1));
    }

    view->show();
    return app.exec();
}