mainwindow.cpp Example File

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#include <QtWidgets> #include "mainwindow.h" MainWindow::MainWindow() : textEdit(new QPlainTextEdit) { setCentralWidget(textEdit); createActions(); createStatusBar(); readSettings(); connect(textEdit->document(), &QTextDocument::contentsChanged, this, &MainWindow::documentWasModified); #ifndef QT_NO_SESSIONMANAGER QGuiApplication::setFallbackSessionManagementEnabled(false); connect(qApp, &QGuiApplication::commitDataRequest, this, &MainWindow::commitData); #endif setCurrentFile(QString()); setUnifiedTitleAndToolBarOnMac(true); } void MainWindow::closeEvent(QCloseEvent *event) { if (maybeSave()) { writeSettings(); event->accept(); } else { event->ignore(); } } void MainWindow::newFile() { if (maybeSave()) { textEdit->clear(); setCurrentFile(QString()); } } void MainWindow::open() { if (maybeSave()) { QString fileName = QFileDialog::getOpenFileName(this); if (!fileName.isEmpty()) loadFile(fileName); } } bool MainWindow::save() { if (curFile.isEmpty()) { return saveAs(); } else { return saveFile(curFile); } } bool MainWindow::saveAs() { QFileDialog dialog(this); dialog.setWindowModality(Qt::WindowModal); dialog.setAcceptMode(QFileDialog::AcceptSave); if (dialog.exec() != QDialog::Accepted) return false; return saveFile(dialog.selectedFiles().first()); } void MainWindow::about() { QMessageBox::about(this, tr("About Application"), tr("The <b>Application</b> example demonstrates how to " "write modern GUI applications using Qt, with a menu bar, " "toolbars, and a status bar.")); } void MainWindow::documentWasModified() { setWindowModified(textEdit->document()->isModified()); } void MainWindow::createActions() { QMenu *fileMenu = menuBar()->addMenu(tr("&File")); QToolBar *fileToolBar = addToolBar(tr("File")); const QIcon newIcon = QIcon::fromTheme("document-new", QIcon(":/images/new.png")); QAction *newAct = new QAction(newIcon, tr("&New"), this); newAct->setShortcuts(QKeySequence::New); newAct->setStatusTip(tr("Create a new file")); connect(newAct, &QAction::triggered, this, &MainWindow::newFile); fileMenu->addAction(newAct); fileToolBar->addAction(newAct); const QIcon openIcon = QIcon::fromTheme("document-open", QIcon(":/images/open.png")); QAction *openAct = new QAction(openIcon, tr("&Open..."), this); openAct->setShortcuts(QKeySequence::Open); openAct->setStatusTip(tr("Open an existing file")); connect(openAct, &QAction::triggered, this, &MainWindow::open); fileMenu->addAction(openAct); fileToolBar->addAction(openAct); const QIcon saveIcon = QIcon::fromTheme("document-save", QIcon(":/images/save.png")); QAction *saveAct = new QAction(saveIcon, tr("&Save"), this); saveAct->setShortcuts(QKeySequence::Save); saveAct->setStatusTip(tr("Save the document to disk")); connect(saveAct, &QAction::triggered, this, &MainWindow::save); fileMenu->addAction(saveAct); fileToolBar->addAction(saveAct); const QIcon saveAsIcon = QIcon::fromTheme("document-save-as"); QAction *saveAsAct = fileMenu->addAction(saveAsIcon, tr("Save &As..."), this, &MainWindow::saveAs); saveAsAct->setShortcuts(QKeySequence::SaveAs); saveAsAct->setStatusTip(tr("Save the document under a new name")); fileMenu->addSeparator(); const QIcon exitIcon = QIcon::fromTheme("application-exit"); QAction *exitAct = fileMenu->addAction(exitIcon, tr("E&xit"), this, &QWidget::close); exitAct->setShortcuts(QKeySequence::Quit); exitAct->setStatusTip(tr("Exit the application")); QMenu *editMenu = menuBar()->addMenu(tr("&Edit")); QToolBar *editToolBar = addToolBar(tr("Edit")); #ifndef QT_NO_CLIPBOARD const QIcon cutIcon = QIcon::fromTheme("edit-cut", QIcon(":/images/cut.png")); QAction *cutAct = new QAction(cutIcon, tr("Cu&t"), this); cutAct->setShortcuts(QKeySequence::Cut); cutAct->setStatusTip(tr("Cut the current selection's contents to the " "clipboard")); connect(cutAct, &QAction::triggered, textEdit, &QPlainTextEdit::cut); editMenu->addAction(cutAct); editToolBar->addAction(cutAct); const QIcon copyIcon = QIcon::fromTheme("edit-copy", QIcon(":/images/copy.png")); QAction *copyAct = new QAction(copyIcon, tr("&Copy"), this); copyAct->setShortcuts(QKeySequence::Copy); copyAct->setStatusTip(tr("Copy the current selection's contents to the " "clipboard")); connect(copyAct, &QAction::triggered, textEdit, &QPlainTextEdit::copy); editMenu->addAction(copyAct); editToolBar->addAction(copyAct); const QIcon pasteIcon = QIcon::fromTheme("edit-paste", QIcon(":/images/paste.png")); QAction *pasteAct = new QAction(pasteIcon, tr("&Paste"), this); pasteAct->setShortcuts(QKeySequence::Paste); pasteAct->setStatusTip(tr("Paste the clipboard's contents into the current " "selection")); connect(pasteAct, &QAction::triggered, textEdit, &QPlainTextEdit::paste); editMenu->addAction(pasteAct); editToolBar->addAction(pasteAct); menuBar()->addSeparator(); #endif // !QT_NO_CLIPBOARD QMenu *helpMenu = menuBar()->addMenu(tr("&Help")); QAction *aboutAct = helpMenu->addAction(tr("&About"), this, &MainWindow::about); aboutAct->setStatusTip(tr("Show the application's About box")); QAction *aboutQtAct = helpMenu->addAction(tr("About &Qt"), qApp, &QApplication::aboutQt); aboutQtAct->setStatusTip(tr("Show the Qt library's About box")); #ifndef QT_NO_CLIPBOARD cutAct->setEnabled(false); copyAct->setEnabled(false); connect(textEdit, &QPlainTextEdit::copyAvailable, cutAct, &QAction::setEnabled); connect(textEdit, &QPlainTextEdit::copyAvailable, copyAct, &QAction::setEnabled); #endif // !QT_NO_CLIPBOARD } void MainWindow::createStatusBar() { statusBar()->showMessage(tr("Ready")); } void MainWindow::readSettings() { QSettings settings(QCoreApplication::organizationName(), QCoreApplication::applicationName()); const QByteArray geometry = settings.value("geometry", QByteArray()).toByteArray(); if (geometry.isEmpty()) { const QRect availableGeometry = QApplication::desktop()->availableGeometry(this); resize(availableGeometry.width() / 3, availableGeometry.height() / 2); move((availableGeometry.width() - width()) / 2, (availableGeometry.height() - height()) / 2); } else { restoreGeometry(geometry); } } void MainWindow::writeSettings() { QSettings settings(QCoreApplication::organizationName(), QCoreApplication::applicationName()); settings.setValue("geometry", saveGeometry()); } bool MainWindow::maybeSave() { if (!textEdit->document()->isModified()) return true; const QMessageBox::StandardButton ret = QMessageBox::warning(this, tr("Application"), tr("The document has been modified.\n" "Do you want to save your changes?"), QMessageBox::Save | QMessageBox::Discard | QMessageBox::Cancel); switch (ret) { case QMessageBox::Save: return save(); case QMessageBox::Cancel: return false; default: break; } return true; } void MainWindow::loadFile(const QString &fileName) { QFile file(fileName); if (! | QFile::Text)) { QMessageBox::warning(this, tr("Application"), tr("Cannot read file %1:\n%2.") .arg(QDir::toNativeSeparators(fileName), file.errorString())); return; } QTextStream in(&file); #ifndef QT_NO_CURSOR QApplication::setOverrideCursor(Qt::WaitCursor); #endif textEdit->setPlainText(in.readAll()); #ifndef QT_NO_CURSOR QApplication::restoreOverrideCursor(); #endif setCurrentFile(fileName); statusBar()->showMessage(tr("File loaded"), 2000); } bool MainWindow::saveFile(const QString &fileName) { QFile file(fileName); if (! | QFile::Text)) { QMessageBox::warning(this, tr("Application"), tr("Cannot write file %1:\n%2.") .arg(QDir::toNativeSeparators(fileName), file.errorString())); return false; } QTextStream out(&file); #ifndef QT_NO_CURSOR QApplication::setOverrideCursor(Qt::WaitCursor); #endif out << textEdit->toPlainText(); #ifndef QT_NO_CURSOR QApplication::restoreOverrideCursor(); #endif setCurrentFile(fileName); statusBar()->showMessage(tr("File saved"), 2000); return true; } void MainWindow::setCurrentFile(const QString &fileName) { curFile = fileName; textEdit->document()->setModified(false); setWindowModified(false); QString shownName = curFile; if (curFile.isEmpty()) shownName = "untitled.txt"; setWindowFilePath(shownName); } QString MainWindow::strippedName(const QString &fullFileName) { return QFileInfo(fullFileName).fileName(); } #ifndef QT_NO_SESSIONMANAGER void MainWindow::commitData(QSessionManager &manager) { if (manager.allowsInteraction()) { if (!maybeSave()) manager.cancel(); } else { // Non-interactive: save without asking if (textEdit->document()->isModified()) save(); } } #endif

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