Polish the widgets/mainwindows/sdi example.

- Introduce Qt 5 signals & slot syntax.
- Use QCommandLineParser to obtain file arguments, factor
  out positioning into tile() function to be able to
  use it from command line and open/new slots.
- Merge MainWindow::createMenus()/createQToolBars()
  into MainWindow::createActions(), removing the need
  to store the actions as member variables.
  Use QMenu::addAction() for brevity.
- Use QIcon::fromTheme() to obtain system icons and use
  resource icons as fallback.
- Rewrite settings code to use
  QWidget::saveGeometry(), Widget::restoreGeometry() since
  saving size and position does not work well with multiple
  screens. Query the available size when determining
  the initial size instead of using hard-coded values
  for High-DPI screens.
- Fix minor issues in code, use multi-argument version
  of QString::arg(), QDir::toNativeSeparators() to
  present file paths to the user and and static method invocation.
- Fix snippet references accordingly.

Change-Id: I3ea0372bc7ff82247192f54620289352fb68d60f
Reviewed-by: Olivier Goffart (Woboq GmbH) <ogoffart@woboq.com>

examples/widgets/mainwindows/sdi/main.cpp

@@ -39,6 +39,7 @@
 ****************************************************************************/
 
 #include <QApplication>
+#include <QCommandLineParser>
 
 #include "mainwindow.h"
 
@@ -46,9 +47,27 @@ int main(int argc, char *argv[])
 {
     Q_INIT_RESOURCE(sdi);
     QApplication app(argc, argv);
-    app.setApplicationName("SDI Example");
+    QCoreApplication::setApplicationName("SDI Example");
-    app.setOrganizationName("QtProject");
+    QCoreApplication::setOrganizationName("QtProject");
-    MainWindow *mainWin = new MainWindow;
+    QCoreApplication::setApplicationVersion(QT_VERSION_STR);
+    QCommandLineParser parser;
+    parser.setApplicationDescription(QCoreApplication::applicationName());
+    parser.addHelpOption();
+    parser.addVersionOption();
+    parser.addPositionalArgument("file", "The file(s) to open.");
+    parser.process(app);
+
+    MainWindow *mainWin = Q_NULLPTR;
+    foreach (const QString &file, parser.positionalArguments()) {
+        MainWindow *newWin = new MainWindow(file);
+        newWin->tile(mainWin);
+        newWin->show();
+        mainWin = newWin;
+    }
+
+    if (!mainWin)
+        mainWin = new MainWindow;
     mainWin->show();
+
     return app.exec();
 }

examples/widgets/mainwindows/sdi/mainwindow.cpp

@@ -45,7 +45,7 @@
 MainWindow::MainWindow()
 {
     init();
-    setCurrentFile("");
+    setCurrentFile(QString());
 }
 
 MainWindow::MainWindow(const QString &fileName)
@@ -67,44 +67,41 @@ void MainWindow::closeEvent(QCloseEvent *event)
 void MainWindow::newFile()
 {
     MainWindow *other = new MainWindow;
-    other->move(x() + 40, y() + 40);
+    other->tile(this);
     other->show();
 }
 
 void MainWindow::open()
 {
-    QString fileName = QFileDialog::getOpenFileName(this);
+    const QString fileName = QFileDialog::getOpenFileName(this);
-    if (!fileName.isEmpty()) {
+    if (fileName.isEmpty())
-        MainWindow *existing = findMainWindow(fileName);
+        return;
-        if (existing) {
-            existing->show();
-            existing->raise();
-            existing->activateWindow();
-            return;
-        }
 
-        if (isUntitled && textEdit->document()->isEmpty()
+    MainWindow *existing = findMainWindow(fileName);
-                && !isWindowModified()) {
+    if (existing) {
-            loadFile(fileName);
+        existing->show();
-        } else {
+        existing->raise();
-            MainWindow *other = new MainWindow(fileName);
+        existing->activateWindow();
-            if (other->isUntitled) {
+        return;
-                delete other;
-                return;
-            }
-            other->move(x() + 40, y() + 40);
-            other->show();
-        }
     }
+
+    if (isUntitled && textEdit->document()->isEmpty() && !isWindowModified()) {
+        loadFile(fileName);
+        return;
+    }
+
+    MainWindow *other = new MainWindow(fileName);
+    if (other->isUntitled) {
+        delete other;
+        return;
+    }
+    other->tile(this);
+    other->show();
 }
 
 bool MainWindow::save()
 {
-    if (isUntitled) {
+    return isUntitled ? saveAs() : saveFile(curFile);
-        return saveAs();
-    } else {
-        return saveFile(curFile);
-    }
 }
 
 bool MainWindow::saveAs()
@@ -139,123 +136,118 @@ void MainWindow::init()
     setCentralWidget(textEdit);
 
     createActions();
-    createMenus();
-    createToolBars();
     createStatusBar();
 
     readSettings();
 
-    connect(textEdit->document(), SIGNAL(contentsChanged()),
+    connect(textEdit->document(), &QTextDocument::contentsChanged,
-            this, SLOT(documentWasModified()));
+            this, &MainWindow::documentWasModified);
 
     setUnifiedTitleAndToolBarOnMac(true);
 }
 
+void MainWindow::tile(const QMainWindow *previous)
+{
+    if (!previous)
+        return;
+    int topFrameWidth = previous->geometry().top() - previous->pos().y();
+    if (!topFrameWidth)
+        topFrameWidth = 40;
+    const QPoint pos = previous->pos() + 2 * QPoint(topFrameWidth, topFrameWidth);
+    if (QApplication::desktop()->availableGeometry(this).contains(rect().bottomRight() + pos))
+        move(pos);
+}
+
+//! [implicit tr context]
 void MainWindow::createActions()
 {
-    newAct = new QAction(QIcon(":/images/new.png"), tr("&New"), this);
+    QMenu *fileMenu = menuBar()->addMenu(tr("&File"));
+//! [implicit tr context]
+    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, SIGNAL(triggered()), this, SLOT(newFile()));
+    connect(newAct, &QAction::triggered, this, &MainWindow::newFile);
+    fileMenu->addAction(newAct);
+    fileToolBar->addAction(newAct);
 
-    openAct = new QAction(QIcon(":/images/open.png"), tr("&Open..."), this);
+    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, SIGNAL(triggered()), this, SLOT(open()));
+    connect(openAct, &QAction::triggered, this, &MainWindow::open);
+    fileMenu->addAction(openAct);
+    fileToolBar->addAction(openAct);
 
-    saveAct = new QAction(QIcon(":/images/save.png"), tr("&Save"), this);
+    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, SIGNAL(triggered()), this, SLOT(save()));
+    connect(saveAct, &QAction::triggered, this, &MainWindow::save);
+    fileMenu->addAction(saveAct);
+    fileToolBar->addAction(saveAct);
 
-    saveAsAct = new QAction(tr("Save &As..."), this);
+    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"));
-    connect(saveAsAct, SIGNAL(triggered()), this, SLOT(saveAs()));
 
-    closeAct = new QAction(tr("&Close"), this);
+    fileMenu->addSeparator();
+
+    QAction *closeAct = fileMenu->addAction(tr("&Close"), this, &QWidget::close);
     closeAct->setShortcut(tr("Ctrl+W"));
     closeAct->setStatusTip(tr("Close this window"));
-    connect(closeAct, SIGNAL(triggered()), this, SLOT(close()));
 
-    exitAct = new QAction(tr("E&xit"), this);
+    const QIcon exitIcon = QIcon::fromTheme("application-exit");
+    QAction *exitAct = fileMenu->addAction(exitIcon, tr("E&xit"), qApp, &QApplication::closeAllWindows);
     exitAct->setShortcuts(QKeySequence::Quit);
     exitAct->setStatusTip(tr("Exit the application"));
-    connect(exitAct, SIGNAL(triggered()), qApp, SLOT(closeAllWindows()));
 
-    cutAct = new QAction(QIcon(":/images/cut.png"), tr("Cu&t"), this);
+    QMenu *editMenu = menuBar()->addMenu(tr("&Edit"));
+    QToolBar *editToolBar = addToolBar(tr("Edit"));
+
+    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, SIGNAL(triggered()), textEdit, SLOT(cut()));
+    connect(cutAct, &QAction::triggered, textEdit, &QTextEdit::cut);
+    editMenu->addAction(cutAct);
+    editToolBar->addAction(cutAct);
 
-    copyAct = new QAction(QIcon(":/images/copy.png"), tr("&Copy"), this);
+    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, SIGNAL(triggered()), textEdit, SLOT(copy()));
+    connect(copyAct, &QAction::triggered, textEdit, &QTextEdit::copy);
+    editMenu->addAction(copyAct);
+    editToolBar->addAction(copyAct);
 
-    pasteAct = new QAction(QIcon(":/images/paste.png"), tr("&Paste"), this);
+    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, SIGNAL(triggered()), textEdit, SLOT(paste()));
+    connect(pasteAct, &QAction::triggered, textEdit, &QTextEdit::paste);
-
-    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()));
-
-
-    cutAct->setEnabled(false);
-    copyAct->setEnabled(false);
-    connect(textEdit, SIGNAL(copyAvailable(bool)),
-            cutAct, SLOT(setEnabled(bool)));
-    connect(textEdit, SIGNAL(copyAvailable(bool)),
-            copyAct, SLOT(setEnabled(bool)));
-}
-
-//! [implicit tr context]
-void MainWindow::createMenus()
-{
-    fileMenu = menuBar()->addMenu(tr("&File"));
-//! [implicit tr context]
-    fileMenu->addAction(newAct);
-    fileMenu->addAction(openAct);
-    fileMenu->addAction(saveAct);
-    fileMenu->addAction(saveAsAct);
-    fileMenu->addSeparator();
-    fileMenu->addAction(closeAct);
-    fileMenu->addAction(exitAct);
-
-    editMenu = menuBar()->addMenu(tr("&Edit"));
-    editMenu->addAction(cutAct);
-    editMenu->addAction(copyAct);
     editMenu->addAction(pasteAct);
+    editToolBar->addAction(pasteAct);
 
     menuBar()->addSeparator();
 
-    helpMenu = menuBar()->addMenu(tr("&Help"));
+    QMenu *helpMenu = menuBar()->addMenu(tr("&Help"));
-    helpMenu->addAction(aboutAct);
+    QAction *aboutAct = helpMenu->addAction(tr("&About"), this, &MainWindow::about);
-    helpMenu->addAction(aboutQtAct);
+    aboutAct->setStatusTip(tr("Show the application's About box"));
-}
 
-void MainWindow::createToolBars()
+    QAction *aboutQtAct = helpMenu->addAction(tr("About &Qt"), qApp, &QApplication::aboutQt);
-{
+    aboutQtAct->setStatusTip(tr("Show the Qt library's About box"));
-//! [0]
-    fileToolBar = addToolBar(tr("File"));
-    fileToolBar->addAction(newAct);
-    fileToolBar->addAction(openAct);
-//! [0]
-    fileToolBar->addAction(saveAct);
 
-    editToolBar = addToolBar(tr("Edit"));
+    cutAct->setEnabled(false);
-    editToolBar->addAction(cutAct);
+    copyAct->setEnabled(false);
-    editToolBar->addAction(copyAct);
+    connect(textEdit, &QTextEdit::copyAvailable, cutAct, &QAction::setEnabled);
-    editToolBar->addAction(pasteAct);
+    connect(textEdit, &QTextEdit::copyAvailable, copyAct, &QAction::setEnabled);
 }
 
 void MainWindow::createStatusBar()
@@ -265,33 +257,41 @@ void MainWindow::createStatusBar()
 
 void MainWindow::readSettings()
 {
-    QSettings settings;
+    QSettings settings(QCoreApplication::organizationName(), QCoreApplication::applicationName());
-    QPoint pos = settings.value("pos", QPoint(200, 200)).toPoint();
+    const QByteArray geometry = settings.value("geometry", QByteArray()).toByteArray();
-    QSize size = settings.value("size", QSize(400, 400)).toSize();
+    if (geometry.isEmpty()) {
-    move(pos);
+        const QRect availableGeometry = QApplication::desktop()->availableGeometry(this);
-    resize(size);
+        resize(availableGeometry.width() / 3, availableGeometry.height() / 2);
+        move((availableGeometry.width() - width()) / 2,
+             (availableGeometry.height() - height()) / 2);
+    } else {
+        restoreGeometry(geometry);
+    }
 }
 
 void MainWindow::writeSettings()
 {
-    QSettings settings;
+    QSettings settings(QCoreApplication::organizationName(), QCoreApplication::applicationName());
-    settings.setValue("pos", pos());
+    settings.setValue("geometry", saveGeometry());
-    settings.setValue("size", size());
 }
 
 bool MainWindow::maybeSave()
 {
-    if (textEdit->document()->isModified()) {
+    if (!textEdit->document()->isModified())
-        QMessageBox::StandardButton ret;
+        return true;
-        ret = QMessageBox::warning(this, tr("SDI"),
+    const QMessageBox::StandardButton ret
-                     tr("The document has been modified.\n"
+        = QMessageBox::warning(this, tr("SDI"),
-                        "Do you want to save your changes?"),
+                               tr("The document has been modified.\n"
-                     QMessageBox::Save | QMessageBox::Discard
+                                  "Do you want to save your changes?"),
-                     | QMessageBox::Cancel);
+                               QMessageBox::Save | QMessageBox::Discard
-        if (ret == QMessageBox::Save)
+                               | QMessageBox::Cancel);
-            return save();
+    switch (ret) {
-        else if (ret == QMessageBox::Cancel)
+    case QMessageBox::Save:
-            return false;
+        return save();
+    case QMessageBox::Cancel:
+        return false;
+    default:
+        break;
     }
     return true;
 }
@@ -303,8 +303,7 @@ void MainWindow::loadFile(const QString &fileName)
     if (!file.open(QFile::ReadOnly | QFile::Text)) {
         QMessageBox::warning(this, tr("SDI"),
                              tr("Cannot read file %1:\n%2.")
-                             .arg(fileName)
+                             .arg(QDir::toNativeSeparators(fileName), file.errorString()));
-                             .arg(file.errorString()));
         return;
     }
 
@@ -323,8 +322,7 @@ bool MainWindow::saveFile(const QString &fileName)
     if (!file.open(QFile::WriteOnly | QFile::Text)) {
         QMessageBox::warning(this, tr("SDI"),
                              tr("Cannot write file %1:\n%2.")
-                             .arg(fileName)
+                             .arg(QDir::toNativeSeparators(fileName), file.errorString()));
-                             .arg(file.errorString()));
         return false;
     }
 
@@ -359,14 +357,15 @@ QString MainWindow::strippedName(const QString &fullFileName)
     return QFileInfo(fullFileName).fileName();
 }
 
-MainWindow *MainWindow::findMainWindow(const QString &fileName)
+MainWindow *MainWindow::findMainWindow(const QString &fileName) const
 {
     QString canonicalFilePath = QFileInfo(fileName).canonicalFilePath();
 
-    foreach (QWidget *widget, qApp->topLevelWidgets()) {
+    foreach (QWidget *widget, QApplication::topLevelWidgets()) {
         MainWindow *mainWin = qobject_cast<MainWindow *>(widget);
         if (mainWin && mainWin->curFile == canonicalFilePath)
             return mainWin;
     }
+
     return 0;
 }

examples/widgets/mainwindows/sdi/mainwindow.h

@@ -42,6 +42,7 @@
 #define MAINWINDOW_H
 
 #include <QMainWindow>
+#include <QList>
 
 QT_BEGIN_NAMESPACE
 class QAction;
@@ -57,7 +58,9 @@ class MainWindow : public QMainWindow
 public:
     MainWindow();
 //! [class definition with macro]
-    MainWindow(const QString &fileName);
+    explicit MainWindow(const QString &fileName);
+
+    void tile(const QMainWindow *previous);
 
 protected:
     void closeEvent(QCloseEvent *event) Q_DECL_OVERRIDE;
@@ -73,8 +76,6 @@ private slots:
 private:
     void init();
     void createActions();
-    void createMenus();
-    void createToolBars();
     void createStatusBar();
     void readSettings();
     void writeSettings();
@@ -82,29 +83,12 @@ private:
     void loadFile(const QString &fileName);
     bool saveFile(const QString &fileName);
     void setCurrentFile(const QString &fileName);
-    QString strippedName(const QString &fullFileName);
+    static QString strippedName(const QString &fullFileName);
-    MainWindow *findMainWindow(const QString &fileName);
+    MainWindow *findMainWindow(const QString &fileName) const;
 
     QTextEdit *textEdit;
     QString curFile;
     bool isUntitled;
-
-    QMenu *fileMenu;
-    QMenu *editMenu;
-    QMenu *helpMenu;
-    QToolBar *fileToolBar;
-    QToolBar *editToolBar;
-    QAction *newAct;
-    QAction *openAct;
-    QAction *saveAct;
-    QAction *saveAsAct;
-    QAction *closeAct;
-    QAction *exitAct;
-    QAction *cutAct;
-    QAction *copyAct;
-    QAction *pasteAct;
-    QAction *aboutAct;
-    QAction *aboutQtAct;
 };
 
 #endif

src/widgets/doc/src/windows-and-dialogs/mainwindow.qdoc

@@ -226,7 +226,11 @@
     We create a toolbar as a child of the main window, and add the desired
     actions to it:
 
-    \snippet mainwindows/sdi/mainwindow.cpp 0
+    \code
+    fileToolBar = addToolBar(tr("File"));
+    fileToolBar->addAction(newAct);
+    fileToolBar->addAction(openAct);
+    \endcode
     \dots
     \snippet code/doc_src_qt4-mainwindow.cpp 1