qt5base-lts/examples/widgets/mainwindows/application/mainwindow.cpp
Friedemann Kleint 8c9e41cc78 Use QSaveFile in MainWindow examples
QSaveFile should preferably be used by editor applications to catch
write errors.

Task-number: QTBUG-60635
Change-Id: Ia609435871b56b45714c3dd3d32bbc85b5cb4dd5
Reviewed-by: Paul Wicking <paul.wicking@qt.io>
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
2019-06-12 09:29:31 +02:00

419 lines
13 KiB
C++

/****************************************************************************
**
** Copyright (C) 2016 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of the examples of the Qt Toolkit.
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//! [0]
#include <QtWidgets>
#include "mainwindow.h"
//! [0]
//! [1]
MainWindow::MainWindow()
: textEdit(new QPlainTextEdit)
//! [1] //! [2]
{
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);
}
//! [2]
//! [3]
void MainWindow::closeEvent(QCloseEvent *event)
//! [3] //! [4]
{
if (maybeSave()) {
writeSettings();
event->accept();
} else {
event->ignore();
}
}
//! [4]
//! [5]
void MainWindow::newFile()
//! [5] //! [6]
{
if (maybeSave()) {
textEdit->clear();
setCurrentFile(QString());
}
}
//! [6]
//! [7]
void MainWindow::open()
//! [7] //! [8]
{
if (maybeSave()) {
QString fileName = QFileDialog::getOpenFileName(this);
if (!fileName.isEmpty())
loadFile(fileName);
}
}
//! [8]
//! [9]
bool MainWindow::save()
//! [9] //! [10]
{
if (curFile.isEmpty()) {
return saveAs();
} else {
return saveFile(curFile);
}
}
//! [10]
//! [11]
bool MainWindow::saveAs()
//! [11] //! [12]
{
QFileDialog dialog(this);
dialog.setWindowModality(Qt::WindowModal);
dialog.setAcceptMode(QFileDialog::AcceptSave);
if (dialog.exec() != QDialog::Accepted)
return false;
return saveFile(dialog.selectedFiles().first());
}
//! [12]
//! [13]
void MainWindow::about()
//! [13] //! [14]
{
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."));
}
//! [14]
//! [15]
void MainWindow::documentWasModified()
//! [15] //! [16]
{
setWindowModified(textEdit->document()->isModified());
}
//! [16]
//! [17]
void MainWindow::createActions()
//! [17] //! [18]
{
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);
//! [19]
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);
//! [18] //! [19]
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"));
//! [20]
fileMenu->addSeparator();
const QIcon exitIcon = QIcon::fromTheme("application-exit");
QAction *exitAct = fileMenu->addAction(exitIcon, tr("E&xit"), this, &QWidget::close);
exitAct->setShortcuts(QKeySequence::Quit);
//! [20]
exitAct->setStatusTip(tr("Exit the application"));
//! [21]
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);
//! [21]
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"));
//! [22]
QAction *aboutQtAct = helpMenu->addAction(tr("About &Qt"), qApp, &QApplication::aboutQt);
aboutQtAct->setStatusTip(tr("Show the Qt library's About box"));
//! [22]
//! [23]
#ifndef QT_NO_CLIPBOARD
cutAct->setEnabled(false);
//! [23] //! [24]
copyAct->setEnabled(false);
connect(textEdit, &QPlainTextEdit::copyAvailable, cutAct, &QAction::setEnabled);
connect(textEdit, &QPlainTextEdit::copyAvailable, copyAct, &QAction::setEnabled);
#endif // !QT_NO_CLIPBOARD
}
//! [24]
//! [32]
void MainWindow::createStatusBar()
//! [32] //! [33]
{
statusBar()->showMessage(tr("Ready"));
}
//! [33]
//! [34] //! [35]
void MainWindow::readSettings()
//! [34] //! [36]
{
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);
}
}
//! [35] //! [36]
//! [37] //! [38]
void MainWindow::writeSettings()
//! [37] //! [39]
{
QSettings settings(QCoreApplication::organizationName(), QCoreApplication::applicationName());
settings.setValue("geometry", saveGeometry());
}
//! [38] //! [39]
//! [40]
bool MainWindow::maybeSave()
//! [40] //! [41]
{
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;
}
//! [41]
//! [42]
void MainWindow::loadFile(const QString &fileName)
//! [42] //! [43]
{
QFile file(fileName);
if (!file.open(QFile::ReadOnly | 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
QGuiApplication::setOverrideCursor(Qt::WaitCursor);
#endif
textEdit->setPlainText(in.readAll());
#ifndef QT_NO_CURSOR
QGuiApplication::restoreOverrideCursor();
#endif
setCurrentFile(fileName);
statusBar()->showMessage(tr("File loaded"), 2000);
}
//! [43]
//! [44]
bool MainWindow::saveFile(const QString &fileName)
//! [44] //! [45]
{
QString errorMessage;
QGuiApplication::setOverrideCursor(Qt::WaitCursor);
QSaveFile file(fileName);
if (file.open(QFile::WriteOnly | QFile::Text)) {
QTextStream out(&file);
out << textEdit->toPlainText();
if (!file.commit()) {
errorMessage = tr("Cannot write file %1:\n%2.")
.arg(QDir::toNativeSeparators(fileName), file.errorString());
}
} else {
errorMessage = tr("Cannot open file %1 for writing:\n%2.")
.arg(QDir::toNativeSeparators(fileName), file.errorString());
}
QGuiApplication::restoreOverrideCursor();
if (!errorMessage.isEmpty()) {
QMessageBox::warning(this, tr("Application"), errorMessage);
return false;
}
setCurrentFile(fileName);
statusBar()->showMessage(tr("File saved"), 2000);
return true;
}
//! [45]
//! [46]
void MainWindow::setCurrentFile(const QString &fileName)
//! [46] //! [47]
{
curFile = fileName;
textEdit->document()->setModified(false);
setWindowModified(false);
QString shownName = curFile;
if (curFile.isEmpty())
shownName = "untitled.txt";
setWindowFilePath(shownName);
}
//! [47]
//! [48]
QString MainWindow::strippedName(const QString &fullFileName)
//! [48] //! [49]
{
return QFileInfo(fullFileName).fileName();
}
//! [49]
#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