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<title>Qt 4.2: mainwindow.cpp Example File (mainwindows/recentfiles/mainwindow.cpp)</title>
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<pre> /****************************************************************************
**
** Copyright (C) 2004-2006 Trolltech ASA. All rights reserved.
**
** This file is part of the example classes of the Qt Toolkit.
**
** This file may be used under the terms of the GNU General Public
** License version 2.0 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 GNU
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****************************************************************************/
#include <QtGui>
#include "mainwindow.h"
MainWindow::MainWindow()
{
setAttribute(Qt::WA_DeleteOnClose);
textEdit = new QTextEdit;
setCentralWidget(textEdit);
createActions();
createMenus();
(void)statusBar();
setWindowTitle(tr("Recent Files"));
resize(400, 300);
}
void MainWindow::newFile()
{
MainWindow *other = new MainWindow;
other->show();
}
void MainWindow::open()
{
QString fileName = QFileDialog::getOpenFileName(this);
if (!fileName.isEmpty())
loadFile(fileName);
}
void MainWindow::save()
{
if (curFile.isEmpty())
saveAs();
else
saveFile(curFile);
}
void MainWindow::saveAs()
{
QString fileName = QFileDialog::getSaveFileName(this);
if (fileName.isEmpty())
return;
if (QFile::exists(fileName)) {
QMessageBox::StandardButton ret;
ret = QMessageBox::warning(this, tr("Recent Files"),
tr("File %1 already exists.\n"
"Do you want to overwrite it?")
.arg(QDir::toNativeSeparators(fileName)),
QMessageBox::Yes | QMessageBox::Cancel);
if (ret == QMessageBox::Cancel)
return;
}
saveFile(fileName);
}
void MainWindow::openRecentFile()
{
QAction *action = qobject_cast<QAction *>(sender());
if (action)
loadFile(action->data().toString());
}
void MainWindow::about()
{
QMessageBox::about(this, tr("About Recent Files"),
tr("The <b>Recent Files</b> example demonstrates how to provide a "
"recently used file menu in a Qt application."));
}
void MainWindow::createActions()
{
newAct = new QAction(tr("&New"), this);
newAct->setShortcut(tr("Ctrl+N"));
newAct->setStatusTip(tr("Create a new file"));
connect(newAct, SIGNAL(triggered()), this, SLOT(newFile()));
openAct = new QAction(tr("&Open..."), this);
openAct->setShortcut(tr("Ctrl+O"));
openAct->setStatusTip(tr("Open an existing file"));
connect(openAct, SIGNAL(triggered()), this, SLOT(open()));
saveAct = new QAction(tr("&Save"), this);
saveAct->setShortcut(tr("Ctrl+S"));
saveAct->setStatusTip(tr("Save the document to disk"));
connect(saveAct, SIGNAL(triggered()), this, SLOT(save()));
saveAsAct = new QAction(tr("Save &As..."), this);
saveAsAct->setStatusTip(tr("Save the document under a new name"));
connect(saveAsAct, SIGNAL(triggered()), this, SLOT(saveAs()));
for (int i = 0; i < MaxRecentFiles; ++i) {
recentFileActs[i] = new QAction(this);
recentFileActs[i]->setVisible(false);
connect(recentFileActs[i], SIGNAL(triggered()),
this, SLOT(openRecentFile()));
}
exitAct = new QAction(tr("E&xit"), this);
exitAct->setShortcut(tr("Ctrl+Q"));
exitAct->setStatusTip(tr("Exit the application"));
connect(exitAct, SIGNAL(triggered()), qApp, SLOT(closeAllWindows()));
aboutAct = new QAction(tr("&About"), this);
aboutAct->setStatusTip(tr("Show the application's About box"));
connect(aboutAct, SIGNAL(triggered()), this, SLOT(about()));
aboutQtAct = new QAction(tr("About &Qt"), this);
aboutQtAct->setStatusTip(tr("Show the Qt library's About box"));
connect(aboutQtAct, SIGNAL(triggered()), qApp, SLOT(aboutQt()));
}
void MainWindow::createMenus()
{
fileMenu = menuBar()->addMenu(tr("&File"));
fileMenu->addAction(newAct);
fileMenu->addAction(openAct);
fileMenu->addAction(saveAct);
fileMenu->addAction(saveAsAct);
separatorAct = fileMenu->addSeparator();
for (int i = 0; i < MaxRecentFiles; ++i)
fileMenu->addAction(recentFileActs[i]);
fileMenu->addSeparator();
fileMenu->addAction(exitAct);
updateRecentFileActions();
menuBar()->addSeparator();
helpMenu = menuBar()->addMenu(tr("&Help"));
helpMenu->addAction(aboutAct);
helpMenu->addAction(aboutQtAct);
}
void MainWindow::loadFile(const QString &fileName)
{
QFile file(fileName);
if (!file.open(QFile::ReadOnly | QFile::Text)) {
QMessageBox::warning(this, tr("Recent Files"),
tr("Cannot read file %1:\n%2.")
.arg(fileName)
.arg(file.errorString()));
return;
}
QTextStream in(&file);
QApplication::setOverrideCursor(Qt::WaitCursor);
textEdit->setPlainText(in.readAll());
QApplication::restoreOverrideCursor();
setCurrentFile(fileName);
statusBar()->showMessage(tr("File loaded"), 2000);
}
void MainWindow::saveFile(const QString &fileName)
{
QFile file(fileName);
if (!file.open(QFile::WriteOnly | QFile::Text)) {
QMessageBox::warning(this, tr("Recent Files"),
tr("Cannot write file %1:\n%2.")
.arg(fileName)
.arg(file.errorString()));
return;
}
QTextStream out(&file);
QApplication::setOverrideCursor(Qt::WaitCursor);
out << textEdit->toPlainText();
QApplication::restoreOverrideCursor();
setCurrentFile(fileName);
statusBar()->showMessage(tr("File saved"), 2000);
}
void MainWindow::setCurrentFile(const QString &fileName)
{
curFile = fileName;
if (curFile.isEmpty())
setWindowTitle(tr("Recent Files"));
else
setWindowTitle(tr("%1 - %2").arg(strippedName(curFile))
.arg(tr("Recent Files")));
QSettings settings("Trolltech", "Recent Files Example");
QStringList files = settings.value("recentFileList").toStringList();
files.removeAll(fileName);
files.prepend(fileName);
while (files.size() > MaxRecentFiles)
files.removeLast();
settings.setValue("recentFileList", files);
foreach (QWidget *widget, QApplication::topLevelWidgets()) {
MainWindow *mainWin = qobject_cast<MainWindow *>(widget);
if (mainWin)
mainWin->updateRecentFileActions();
}
}
void MainWindow::updateRecentFileActions()
{
QSettings settings("Trolltech", "Recent Files Example");
QStringList files = settings.value("recentFileList").toStringList();
int numRecentFiles = qMin(files.size(), (int)MaxRecentFiles);
for (int i = 0; i < numRecentFiles; ++i) {
QString text = tr("&%1 %2").arg(i + 1).arg(strippedName(files[i]));
recentFileActs[i]->setText(text);
recentFileActs[i]->setData(files[i]);
recentFileActs[i]->setVisible(true);
}
for (int j = numRecentFiles; j < MaxRecentFiles; ++j)
recentFileActs[j]->setVisible(false);
separatorAct->setVisible(numRecentFiles > 0);
}
QString MainWindow::strippedName(const QString &fullFileName)
{
return QFileInfo(fullFileName).fileName();
}</pre>
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