mainwindow.cpp Example File | Qt Widgets 5.12.11

- Qt 5.12
- Qt Widgets
- Menus Example
- mainwindow.cpp Example File
- Qt 5.12.11 Reference Documentation

# mainwindow.cpp Example File

mainwindows/menus/mainwindow.cpp

     /****************************************************************************
     **
     ** Copyright (C) 2016 The Qt Company Ltd.
     ** Contact: https://www.qt.io/licensing/
     **
     ** This file is part of the examples of the Qt Toolkit.
     **
     ** $QT_BEGIN_LICENSE:BSD$
     ** Commercial License Usage
     ** Licensees holding valid commercial Qt licenses may use this file in
     ** accordance with the commercial license agreement provided with the
     ** Software or, alternatively, in accordance with the terms contained in
     ** a written agreement between you and The Qt Company. For licensing terms
     ** and conditions see https://www.qt.io/terms-conditions. For further
     ** information use the contact form at https://www.qt.io/contact-us.
     **
     ** BSD License Usage
     ** Alternatively, you may use this file under the terms of the BSD license
     ** as follows:
     **
     ** "Redistribution and use in source and binary forms, with or without
     ** modification, are permitted provided that the following conditions are
     ** met:
     **   * Redistributions of source code must retain the above copyright
     **     notice, this list of conditions and the following disclaimer.
     **   * Redistributions in binary form must reproduce the above copyright
     **     notice, this list of conditions and the following disclaimer in
     **     the documentation and/or other materials provided with the
     **     distribution.
     **   * Neither the name of The Qt Company Ltd nor the names of its
     **     contributors may be used to endorse or promote products derived
     **     from this software without specific prior written permission.
     **
     **
     ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     ** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     ** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     ** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     ** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     ** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     ** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     ** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     ** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
     **
     ** $QT_END_LICENSE$
     **
     ****************************************************************************/

     #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);
     }

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

     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);
     }