Qt 5.6 | Qt Widgets | Menus Example | mainwindow.cpp Example File

Qt 5.6.2 Reference Documentation

# mainwindow.cpp Example File

mainwindows/menus/mainwindow.cpp

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      #include <QtWidgets>

      #include "mainwindow.h"

      MainWindow::MainWindow()
      {
          QWidget *widget = new QWidget;
          setCentralWidget(widget);

          QWidget *topFiller = new QWidget;
          topFiller->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);

          infoLabel = new QLabel(tr("<i>Choose a menu option, or right-click to "
                                    "invoke a context menu</i>"));
          infoLabel->setFrameStyle(QFrame::StyledPanel | QFrame::Sunken);
          infoLabel->setAlignment(Qt::AlignCenter);

          QWidget *bottomFiller = new QWidget;
          bottomFiller->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);

          QVBoxLayout *layout = new QVBoxLayout;
          layout->setMargin(5);
          layout->addWidget(topFiller);
          layout->addWidget(infoLabel);
          layout->addWidget(bottomFiller);
          widget->setLayout(layout);

          createActions();
          createMenus();

          QString message = tr("A context menu is available by right-clicking");
          statusBar()->showMessage(message);

          setWindowTitle(tr("Menus"));
          setMinimumSize(160, 160);
          resize(480, 320);
      }

      void MainWindow::contextMenuEvent(QContextMenuEvent *event)
      {
          QMenu menu(this);
          menu.addAction(cutAct);
          menu.addAction(copyAct);
          menu.addAction(pasteAct);
          menu.exec(event->globalPos());
      }

      void MainWindow::newFile()
      {
          infoLabel->setText(tr("Invoked <b>File|New</b>"));
      }

      void MainWindow::open()
      {
          infoLabel->setText(tr("Invoked <b>File|Open</b>"));
      }

      void MainWindow::save()
      {
          infoLabel->setText(tr("Invoked <b>File|Save</b>"));
      }

      void MainWindow::print()
      {
          infoLabel->setText(tr("Invoked <b>File|Print</b>"));
      }

      void MainWindow::undo()
      {
          infoLabel->setText(tr("Invoked <b>Edit|Undo</b>"));
      }

      void MainWindow::redo()
      {
          infoLabel->setText(tr("Invoked <b>Edit|Redo</b>"));
      }

      void MainWindow::cut()
      {
          infoLabel->setText(tr("Invoked <b>Edit|Cut</b>"));
      }

      void MainWindow::copy()
      {
          infoLabel->setText(tr("Invoked <b>Edit|Copy</b>"));
      }

      void MainWindow::paste()
      {
          infoLabel->setText(tr("Invoked <b>Edit|Paste</b>"));
      }

      void MainWindow::bold()
      {
          infoLabel->setText(tr("Invoked <b>Edit|Format|Bold</b>"));
      }

      void MainWindow::italic()
      {
          infoLabel->setText(tr("Invoked <b>Edit|Format|Italic</b>"));
      }

      void MainWindow::leftAlign()
      {
          infoLabel->setText(tr("Invoked <b>Edit|Format|Left Align</b>"));
      }

      void MainWindow::rightAlign()
      {
          infoLabel->setText(tr("Invoked <b>Edit|Format|Right Align</b>"));
      }

      void MainWindow::justify()
      {
          infoLabel->setText(tr("Invoked <b>Edit|Format|Justify</b>"));
      }

      void MainWindow::center()
      {
          infoLabel->setText(tr("Invoked <b>Edit|Format|Center</b>"));
      }

      void MainWindow::setLineSpacing()
      {
          infoLabel->setText(tr("Invoked <b>Edit|Format|Set Line Spacing</b>"));
      }

      void MainWindow::setParagraphSpacing()
      {
          infoLabel->setText(tr("Invoked <b>Edit|Format|Set Paragraph Spacing</b>"));
      }

      void MainWindow::about()
      {
          infoLabel->setText(tr("Invoked <b>Help|About</b>"));
          QMessageBox::about(this, tr("About Menu"),
                  tr("The <b>Menu</b> example shows how to create "
                     "menu-bar menus and context menus."));
      }

      void MainWindow::aboutQt()
      {
          infoLabel->setText(tr("Invoked <b>Help|About Qt</b>"));
      }

      void MainWindow::createActions()
      {
          newAct = new QAction(tr("&New"), this);
          newAct->setShortcuts(QKeySequence::New);
          newAct->setStatusTip(tr("Create a new file"));
          connect(newAct, &QAction::triggered, this, &MainWindow::newFile);

          openAct = new QAction(tr("&Open..."), this);
          openAct->setShortcuts(QKeySequence::Open);
          openAct->setStatusTip(tr("Open an existing file"));
          connect(openAct, &QAction::triggered, this, &MainWindow::open);

          saveAct = new QAction(tr("&Save"), this);
          saveAct->setShortcuts(QKeySequence::Save);
          saveAct->setStatusTip(tr("Save the document to disk"));
          connect(saveAct, &QAction::triggered, this, &MainWindow::save);

          printAct = new QAction(tr("&Print..."), this);
          printAct->setShortcuts(QKeySequence::Print);
          printAct->setStatusTip(tr("Print the document"));
          connect(printAct, &QAction::triggered, this, &MainWindow::print);

          exitAct = new QAction(tr("E&xit"), this);
          exitAct->setShortcuts(QKeySequence::Quit);
          exitAct->setStatusTip(tr("Exit the application"));
          connect(exitAct, &QAction::triggered, this, &QWidget::close);

          undoAct = new QAction(tr("&Undo"), this);
          undoAct->setShortcuts(QKeySequence::Undo);
          undoAct->setStatusTip(tr("Undo the last operation"));
          connect(undoAct, &QAction::triggered, this, &MainWindow::undo);

          redoAct = new QAction(tr("&Redo"), this);
          redoAct->setShortcuts(QKeySequence::Redo);
          redoAct->setStatusTip(tr("Redo the last operation"));
          connect(redoAct, &QAction::triggered, this, &MainWindow::redo);

          cutAct = new QAction(tr("Cu&t"), this);
          cutAct->setShortcuts(QKeySequence::Cut);
          cutAct->setStatusTip(tr("Cut the current selection's contents to the "
                                  "clipboard"));
          connect(cutAct, &QAction::triggered, this, &MainWindow::cut);

          copyAct = new QAction(tr("&Copy"), this);
          copyAct->setShortcuts(QKeySequence::Copy);
          copyAct->setStatusTip(tr("Copy the current selection's contents to the "
                                   "clipboard"));
          connect(copyAct, &QAction::triggered, this, &MainWindow::copy);

          pasteAct = new QAction(tr("&Paste"), this);
          pasteAct->setShortcuts(QKeySequence::Paste);
          pasteAct->setStatusTip(tr("Paste the clipboard's contents into the current "
                                    "selection"));
          connect(pasteAct, &QAction::triggered, this, &MainWindow::paste);

          boldAct = new QAction(tr("&Bold"), this);
          boldAct->setCheckable(true);
          boldAct->setShortcut(QKeySequence::Bold);
          boldAct->setStatusTip(tr("Make the text bold"));
          connect(boldAct, &QAction::triggered, this, &MainWindow::bold);

          QFont boldFont = boldAct->font();
          boldFont.setBold(true);
          boldAct->setFont(boldFont);

          italicAct = new QAction(tr("&Italic"), this);
          italicAct->setCheckable(true);
          italicAct->setShortcut(QKeySequence::Italic);
          italicAct->setStatusTip(tr("Make the text italic"));
          connect(italicAct, &QAction::triggered, this, &MainWindow::italic);

          QFont italicFont = italicAct->font();
          italicFont.setItalic(true);
          italicAct->setFont(italicFont);

          setLineSpacingAct = new QAction(tr("Set &Line Spacing..."), this);
          setLineSpacingAct->setStatusTip(tr("Change the gap between the lines of a "
                                             "paragraph"));
          connect(setLineSpacingAct, &QAction::triggered, this, &MainWindow::setLineSpacing);

          setParagraphSpacingAct = new QAction(tr("Set &Paragraph Spacing..."), this);
          setParagraphSpacingAct->setStatusTip(tr("Change the gap between paragraphs"));
          connect(setParagraphSpacingAct, &QAction::triggered,
                  this, &MainWindow::setParagraphSpacing);

          aboutAct = new QAction(tr("&About"), this);
          aboutAct->setStatusTip(tr("Show the application's About box"));
          connect(aboutAct, &QAction::triggered, this, &MainWindow::about);

          aboutQtAct = new QAction(tr("About &Qt"), this);
          aboutQtAct->setStatusTip(tr("Show the Qt library's About box"));
          connect(aboutQtAct, &QAction::triggered, qApp, &QApplication::aboutQt);
          connect(aboutQtAct, &QAction::triggered, this, &MainWindow::aboutQt);

          leftAlignAct = new QAction(tr("&Left Align"), this);
          leftAlignAct->setCheckable(true);
          leftAlignAct->setShortcut(tr("Ctrl+L"));
          leftAlignAct->setStatusTip(tr("Left align the selected text"));
          connect(leftAlignAct, &QAction::triggered, this, &MainWindow::leftAlign);

          rightAlignAct = new QAction(tr("&Right Align"), this);
          rightAlignAct->setCheckable(true);
          rightAlignAct->setShortcut(tr("Ctrl+R"));
          rightAlignAct->setStatusTip(tr("Right align the selected text"));
          connect(rightAlignAct, &QAction::triggered, this, &MainWindow::rightAlign);

          justifyAct = new QAction(tr("&Justify"), this);
          justifyAct->setCheckable(true);
          justifyAct->setShortcut(tr("Ctrl+J"));
          justifyAct->setStatusTip(tr("Justify the selected text"));
          connect(justifyAct, &QAction::triggered, this, &MainWindow::justify);

          centerAct = new QAction(tr("&Center"), this);
          centerAct->setCheckable(true);
          centerAct->setShortcut(tr("Ctrl+E"));
          centerAct->setStatusTip(tr("Center the selected text"));
          connect(centerAct, &QAction::triggered, this, &MainWindow::center);

          alignmentGroup = new QActionGroup(this);
          alignmentGroup->addAction(leftAlignAct);
          alignmentGroup->addAction(rightAlignAct);
          alignmentGroup->addAction(justifyAct);
          alignmentGroup->addAction(centerAct);
          leftAlignAct->setChecked(true);
      }

      void MainWindow::createMenus()
      {
          fileMenu = menuBar()->addMenu(tr("&File"));
          fileMenu->addAction(newAct);
          fileMenu->addAction(openAct);
          fileMenu->addAction(saveAct);
          fileMenu->addAction(printAct);
          fileMenu->addSeparator();
          fileMenu->addAction(exitAct);

          editMenu = menuBar()->addMenu(tr("&Edit"));
          editMenu->addAction(undoAct);
          editMenu->addAction(redoAct);
          editMenu->addSeparator();
          editMenu->addAction(cutAct);
          editMenu->addAction(copyAct);
          editMenu->addAction(pasteAct);
          editMenu->addSeparator();

          helpMenu = menuBar()->addMenu(tr("&Help"));
          helpMenu->addAction(aboutAct);
          helpMenu->addAction(aboutQtAct);

          formatMenu = editMenu->addMenu(tr("&Format"));
          formatMenu->addAction(boldAct);
          formatMenu->addAction(italicAct);
          formatMenu->addSeparator()->setText(tr("Alignment"));
          formatMenu->addAction(leftAlignAct);
          formatMenu->addAction(rightAlignAct);
          formatMenu->addAction(justifyAct);
          formatMenu->addAction(centerAct);
          formatMenu->addSeparator();
          formatMenu->addAction(setLineSpacingAct);
          formatMenu->addAction(setParagraphSpacingAct);
      }