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2010-05-25T10:24:55Z

1 версия: Импорт контента...

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==extends QAbstractListModel to create file list model==

<source lang="cpp">
/****************************************************************************
**
** 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();
}

</source>

==persistent indexes==

<source lang="cpp">
/****************************************************************************
**
** 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();
}

</source>

==string list model example==

<source lang="cpp">
/****************************************************************************
**
** 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();
}

</source>

C++/Qt/QAbstractListModel - История изменений

в 14:21, 25 мая 2010

Admin: 1 версия: Импорт контента...

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