Qt 5.11 | Qt Widgets | Main Window | mainwindow.cpp Example File

Qt 5.11.3 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)
      {
          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);
      }