mainwindow.cpp Example File | Qt Widgets 5.12.9

- Qt 5.12
- Qt Widgets
- Main Window
- mainwindow.cpp Example File
- Qt 5.12.9 Reference Documentation

# mainwindow.cpp Example File

mainwindows/mainwindow/mainwindow.cpp

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     #include "mainwindow.h"
     #include "colorswatch.h"
     #include "toolbar.h"

     #include <QAction>
     #include <QLayout>
     #include <QMenu>
     #include <QMenuBar>
     #include <QStatusBar>
     #include <QTextEdit>
     #include <QFile>
     #include <QDataStream>
     #include <QFileDialog>
     #include <QDialogButtonBox>
     #include <QMessageBox>
     #include <QApplication>
     #include <QPainter>
     #include <QMouseEvent>
     #include <QLineEdit>
     #include <QComboBox>
     #include <QLabel>
     #include <QPushButton>
     #include <QTextEdit>
     #include <QDebug>

     static const char message[] =
         "<p><b>Qt Main Window Example</b></p>"

         "<p>This is a demonstration of the QMainWindow, QToolBar and "
         "QDockWidget classes.</p>"

         "<p>The tool bar and dock widgets can be dragged around and rearranged "
         "using the mouse or via the menu.</p>"

         "<p>Each dock widget contains a colored frame and a context "
         "(right-click) menu.</p>"

     #ifdef Q_OS_MAC
         "<p>On OS X, the \"Black\" dock widget has been created as a "
         "<em>Drawer</em>, which is a special kind of QDockWidget.</p>"
     #endif
         ;

     Q_DECLARE_METATYPE(QDockWidget::DockWidgetFeatures)

     MainWindow::MainWindow(const CustomSizeHintMap &customSizeHints,
                            QWidget *parent, Qt::WindowFlags flags)
         : QMainWindow(parent, flags)
     {
         Q_UNUSED(message);
         setObjectName("MainWindow");
         setWindowTitle("Qt Main Window Example");

         QTextEdit *center = new QTextEdit(this);
         center->setReadOnly(true);
         center->setMinimumSize(400, 205);
         setCentralWidget(center);

         setupToolBar();
         setupMenuBar();
         setupDockWidgets(customSizeHints);

         statusBar()->showMessage(tr("Status Bar"));
     }

     void MainWindow::actionTriggered(QAction *action)
     {
         qDebug("action '%s' triggered", action->text().toLocal8Bit().data());
     }

     void MainWindow::setupToolBar()
     {
     #ifdef Q_OS_OSX
         setUnifiedTitleAndToolBarOnMac(true);
     #endif

         for (int i = 0; i < 3; ++i) {
             ToolBar *tb = new ToolBar(QString::fromLatin1("Tool Bar %1").arg(i + 1), this);
             toolBars.append(tb);
             addToolBar(tb);
         }
     }

     void MainWindow::setupMenuBar()
     {
         QMenu *menu = menuBar()->addMenu(tr("&File"));

         menu->addAction(tr("Save layout..."), this, &MainWindow::saveLayout);
         menu->addAction(tr("Load layout..."), this, &MainWindow::loadLayout);
         menu->addAction(tr("Switch layout direction"),this, &MainWindow::switchLayoutDirection);

         menu->addSeparator();
         menu->addAction(tr("&Quit"), this, &QWidget::close);

         mainWindowMenu = menuBar()->addMenu(tr("Main window"));

         QAction *action = mainWindowMenu->addAction(tr("Animated docks"));
         action->setCheckable(true);
         action->setChecked(dockOptions() & AnimatedDocks);
         connect(action, &QAction::toggled, this, &MainWindow::setDockOptions);

         action = mainWindowMenu->addAction(tr("Allow nested docks"));
         action->setCheckable(true);
         action->setChecked(dockOptions() & AllowNestedDocks);
         connect(action, &QAction::toggled, this, &MainWindow::setDockOptions);

         action = mainWindowMenu->addAction(tr("Allow tabbed docks"));
         action->setCheckable(true);
         action->setChecked(dockOptions() & AllowTabbedDocks);
         connect(action, &QAction::toggled, this, &MainWindow::setDockOptions);

         action = mainWindowMenu->addAction(tr("Force tabbed docks"));
         action->setCheckable(true);
         action->setChecked(dockOptions() & ForceTabbedDocks);
         connect(action, &QAction::toggled, this, &MainWindow::setDockOptions);

         action = mainWindowMenu->addAction(tr("Vertical tabs"));
         action->setCheckable(true);
         action->setChecked(dockOptions() & VerticalTabs);
         connect(action, &QAction::toggled, this, &MainWindow::setDockOptions);

         action = mainWindowMenu->addAction(tr("Grouped dragging"));
         action->setCheckable(true);
         action->setChecked(dockOptions() & GroupedDragging);
         connect(action, &QAction::toggled, this, &MainWindow::setDockOptions);

         QMenu *toolBarMenu = menuBar()->addMenu(tr("Tool bars"));
         for (int i = 0; i < toolBars.count(); ++i)
             toolBarMenu->addMenu(toolBars.at(i)->toolbarMenu());

     #ifdef Q_OS_OSX
         toolBarMenu->addSeparator();

         action = toolBarMenu->addAction(tr("Unified"));
         action->setCheckable(true);
         action->setChecked(unifiedTitleAndToolBarOnMac());
         connect(action, &QAction::toggled, this, &QMainWindow::setUnifiedTitleAndToolBarOnMac);
     #endif

         dockWidgetMenu = menuBar()->addMenu(tr("&Dock Widgets"));

         QMenu *aboutMenu = menuBar()->addMenu(tr("About"));
         QAction *aboutAct = aboutMenu->addAction(tr("&About"), this, &MainWindow::about);
         aboutAct->setStatusTip(tr("Show the application's About box"));

         QAction *aboutQtAct = aboutMenu->addAction(tr("About &Qt"), qApp, &QApplication::aboutQt);
         aboutQtAct->setStatusTip(tr("Show the Qt library's About box"));
     }

     void MainWindow::setDockOptions()
     {
         DockOptions opts;
         QList<QAction*> actions = mainWindowMenu->actions();

         if (actions.at(0)->isChecked())
             opts |= AnimatedDocks;
         if (actions.at(1)->isChecked())
             opts |= AllowNestedDocks;
         if (actions.at(2)->isChecked())
             opts |= AllowTabbedDocks;
         if (actions.at(3)->isChecked())
             opts |= ForceTabbedDocks;
         if (actions.at(4)->isChecked())
             opts |= VerticalTabs;
         if (actions.at(5)->isChecked())
             opts |= GroupedDragging;

         QMainWindow::setDockOptions(opts);
     }

     void MainWindow::saveLayout()
     {
         QString fileName
             = QFileDialog::getSaveFileName(this, tr("Save layout"));
         if (fileName.isEmpty())
             return;
         QFile file(fileName);
         if (!file.open(QFile::WriteOnly)) {
             QString msg = tr("Failed to open %1\n%2")
                             .arg(QDir::toNativeSeparators(fileName), file.errorString());
             QMessageBox::warning(this, tr("Error"), msg);
             return;
         }

         QByteArray geo_data = saveGeometry();
         QByteArray layout_data = saveState();

         bool ok = file.putChar((uchar)geo_data.size());
         if (ok)
             ok = file.write(geo_data) == geo_data.size();
         if (ok)
             ok = file.write(layout_data) == layout_data.size();

         if (!ok) {
             QString msg = tr("Error writing to %1\n%2")
                             .arg(QDir::toNativeSeparators(fileName), file.errorString());
             QMessageBox::warning(this, tr("Error"), msg);
             return;
         }
     }

     void MainWindow::loadLayout()
     {
         QString fileName
             = QFileDialog::getOpenFileName(this, tr("Load layout"));
         if (fileName.isEmpty())
             return;
         QFile file(fileName);
         if (!file.open(QFile::ReadOnly)) {
             QString msg = tr("Failed to open %1\n%2")
                             .arg(QDir::toNativeSeparators(fileName), file.errorString());
             QMessageBox::warning(this, tr("Error"), msg);
             return;
         }

         uchar geo_size;
         QByteArray geo_data;
         QByteArray layout_data;

         bool ok = file.getChar((char*)&geo_size);
         if (ok) {
             geo_data = file.read(geo_size);
             ok = geo_data.size() == geo_size;
         }
         if (ok) {
             layout_data = file.readAll();
             ok = layout_data.size() > 0;
         }

         if (ok)
             ok = restoreGeometry(geo_data);
         if (ok)
             ok = restoreState(layout_data);

         if (!ok) {
             QString msg = tr("Error reading %1").arg(QDir::toNativeSeparators(fileName));
             QMessageBox::warning(this, tr("Error"), msg);
             return;
         }
     }

     static QAction *addCornerAction(const QString &text, QMainWindow *mw, QMenu *menu, QActionGroup *group,
                                     Qt::Corner c, Qt::DockWidgetArea a)
     {
         QAction *result = menu->addAction(text, mw, [=]() { mw->setCorner(c, a); });
         result->setCheckable(true);
         group->addAction(result);
         return result;
     }

     void MainWindow::setupDockWidgets(const CustomSizeHintMap &customSizeHints)
     {
         qRegisterMetaType<QDockWidget::DockWidgetFeatures>();

         QMenu *cornerMenu = dockWidgetMenu->addMenu(tr("Top left corner"));
         QActionGroup *group = new QActionGroup(this);
         group->setExclusive(true);
         QAction *cornerAction = addCornerAction(tr("Top dock area"), this, cornerMenu, group, Qt::TopLeftCorner, Qt::TopDockWidgetArea);
         cornerAction->setChecked(true);
         addCornerAction(tr("Left dock area"), this, cornerMenu, group, Qt::TopLeftCorner, Qt::LeftDockWidgetArea);

         cornerMenu = dockWidgetMenu->addMenu(tr("Top right corner"));
         group = new QActionGroup(this);
         group->setExclusive(true);
         cornerAction = addCornerAction(tr("Top dock area"), this, cornerMenu, group, Qt::TopRightCorner, Qt::TopDockWidgetArea);
         cornerAction->setChecked(true);
         addCornerAction(tr("Right dock area"), this, cornerMenu, group, Qt::TopRightCorner, Qt::RightDockWidgetArea);

         cornerMenu = dockWidgetMenu->addMenu(tr("Bottom left corner"));
         group = new QActionGroup(this);
         group->setExclusive(true);
         cornerAction = addCornerAction(tr("Bottom dock area"), this, cornerMenu, group, Qt::BottomLeftCorner, Qt::BottomDockWidgetArea);
         cornerAction->setChecked(true);
         addCornerAction(tr("Left dock area"), this, cornerMenu, group, Qt::BottomLeftCorner, Qt::LeftDockWidgetArea);

         cornerMenu = dockWidgetMenu->addMenu(tr("Bottom right corner"));
         group = new QActionGroup(this);
         group->setExclusive(true);
         cornerAction = addCornerAction(tr("Bottom dock area"), this, cornerMenu, group, Qt::BottomRightCorner, Qt::BottomDockWidgetArea);
         cornerAction->setChecked(true);
         addCornerAction(tr("Right dock area"), this, cornerMenu, group, Qt::BottomRightCorner, Qt::RightDockWidgetArea);

         dockWidgetMenu->addSeparator();

         static const struct Set {
             const char * name;
             uint flags;
             Qt::DockWidgetArea area;
         } sets [] = {
     #ifndef Q_OS_MAC
             { "Black", 0, Qt::LeftDockWidgetArea },
     #else
             { "Black", Qt::Drawer, Qt::LeftDockWidgetArea },
     #endif
             { "White", 0, Qt::RightDockWidgetArea },
             { "Red", 0, Qt::TopDockWidgetArea },
             { "Green", 0, Qt::TopDockWidgetArea },
             { "Blue", 0, Qt::BottomDockWidgetArea },
             { "Yellow", 0, Qt::BottomDockWidgetArea }
         };
         const int setCount = sizeof(sets) / sizeof(Set);

         const QIcon qtIcon(QPixmap(":/res/qt.png"));
         for (int i = 0; i < setCount; ++i) {
             ColorSwatch *swatch = new ColorSwatch(tr(sets[i].name), this, Qt::WindowFlags(sets[i].flags));
             if (i % 2)
                 swatch->setWindowIcon(qtIcon);
             if (qstrcmp(sets[i].name, "Blue") == 0) {
                 BlueTitleBar *titlebar = new BlueTitleBar(swatch);
                 swatch->setTitleBarWidget(titlebar);
                 connect(swatch, &QDockWidget::topLevelChanged, titlebar, &BlueTitleBar::updateMask);
                 connect(swatch, &QDockWidget::featuresChanged, titlebar, &BlueTitleBar::updateMask, Qt::QueuedConnection);
             }

             QString name = QString::fromLatin1(sets[i].name);
             if (customSizeHints.contains(name))
                 swatch->setCustomSizeHint(customSizeHints.value(name));

             addDockWidget(sets[i].area, swatch);
             dockWidgetMenu->addMenu(swatch->colorSwatchMenu());
         }

         destroyDockWidgetMenu = new QMenu(tr("Destroy dock widget"), this);
         destroyDockWidgetMenu->setEnabled(false);
         connect(destroyDockWidgetMenu, &QMenu::triggered, this, &MainWindow::destroyDockWidget);

         dockWidgetMenu->addSeparator();
         dockWidgetMenu->addAction(tr("Add dock widget..."), this, &MainWindow::createDockWidget);
         dockWidgetMenu->addMenu(destroyDockWidgetMenu);
     }

     void MainWindow::switchLayoutDirection()
     {
         if (layoutDirection() == Qt::LeftToRight)
             QApplication::setLayoutDirection(Qt::RightToLeft);
         else
             QApplication::setLayoutDirection(Qt::LeftToRight);
     }

     class CreateDockWidgetDialog : public QDialog
     {
     public:
         explicit CreateDockWidgetDialog(QWidget *parent = nullptr);

         QString enteredObjectName() const { return m_objectName->text(); }
         Qt::DockWidgetArea location() const;

     private:
         QLineEdit *m_objectName;
         QComboBox *m_location;
     };

     CreateDockWidgetDialog::CreateDockWidgetDialog(QWidget *parent)
         : QDialog(parent)
         , m_objectName(new QLineEdit(this))
         , m_location(new QComboBox(this))
     {
         setWindowTitle(tr("Add Dock Widget"));
         setWindowFlags(windowFlags() & ~Qt::WindowContextHelpButtonHint);
         QGridLayout *layout = new QGridLayout(this);

         layout->addWidget(new QLabel(tr("Object name:")), 0, 0);
         layout->addWidget(m_objectName, 0, 1);

         layout->addWidget(new QLabel(tr("Location:")), 1, 0);
         m_location->setEditable(false);
         m_location->addItem(tr("Top"));
         m_location->addItem(tr("Left"));
         m_location->addItem(tr("Right"));
         m_location->addItem(tr("Bottom"));
         m_location->addItem(tr("Restore"));
         layout->addWidget(m_location, 1, 1);

         QDialogButtonBox *buttonBox = new QDialogButtonBox(QDialogButtonBox::Ok | QDialogButtonBox::Cancel, this);
         connect(buttonBox, &QDialogButtonBox::rejected, this, &QDialog::reject);
         connect(buttonBox, &QDialogButtonBox::accepted, this, &QDialog::accept);
         layout->addWidget(buttonBox, 2, 0, 1, 2);
     }

     Qt::DockWidgetArea CreateDockWidgetDialog::location() const
     {
         switch (m_location->currentIndex()) {
             case 0: return Qt::TopDockWidgetArea;
             case 1: return Qt::LeftDockWidgetArea;
             case 2: return Qt::RightDockWidgetArea;
             case 3: return Qt::BottomDockWidgetArea;
             default:
                 break;
         }
         return Qt::NoDockWidgetArea;
     }

     void MainWindow::createDockWidget()
     {
         CreateDockWidgetDialog dialog(this);
         if (dialog.exec() == QDialog::Rejected)
             return;

         QDockWidget *dw = new QDockWidget;
         const QString name = dialog.enteredObjectName();
         dw->setObjectName(name);
         dw->setWindowTitle(name);
         dw->setWidget(new QTextEdit);

         Qt::DockWidgetArea area = dialog.location();
         switch (area) {
             case Qt::LeftDockWidgetArea:
             case Qt::RightDockWidgetArea:
             case Qt::TopDockWidgetArea:
             case Qt::BottomDockWidgetArea:
                 addDockWidget(area, dw);
                 break;
             default:
                 if (!restoreDockWidget(dw)) {
                     QMessageBox::warning(this, QString(), tr("Failed to restore dock widget"));
                     delete dw;
                     return;
                 }
                 break;
         }

         extraDockWidgets.append(dw);
         destroyDockWidgetMenu->setEnabled(true);
         destroyDockWidgetMenu->addAction(new QAction(name, this));
     }

     void MainWindow::destroyDockWidget(QAction *action)
     {
         int index = destroyDockWidgetMenu->actions().indexOf(action);
         delete extraDockWidgets.takeAt(index);
         destroyDockWidgetMenu->removeAction(action);
         action->deleteLater();

         if (destroyDockWidgetMenu->isEmpty())
             destroyDockWidgetMenu->setEnabled(false);
     }

     void MainWindow::about()
     {
         QMessageBox::about(this, tr("About MainWindows"), message);
     }