Menus and toolbars in Qt5
last modified October 18, 2023
In this part of the Qt5 C++ programming tutorial, we talk about menus and toolbars in Qt5 applications.
A menubar is a common part of a GUI application. It is a group of commands located in various places called menus. Menus group commands that we can use in an application. Toolbars provide a quick access to the most frequently used commands.
Qt5 simple menu
The first example shows a simple menu.
simple_menu.h
#pragma once
#include <QMainWindow> #include <QApplication>
class SimpleMenu : public QMainWindow {
public: SimpleMenu(QWidget *parent = nullptr); };
This is a header file for our code example.
simple_menu.cpp
#include <QMenu> #include <QMenuBar> #include “simple_menu.h”
SimpleMenu::SimpleMenu(QWidget *parent) : QMainWindow(parent) {
auto *quit = new QAction("&Quit", this);
QMenu *file = menuBar()->addMenu("&File"); file->addAction(quit);
connect(quit, &QAction::triggered, qApp, QApplication::quit); }
We have a menubar, a menu and an action. In order to work with menus, we must inherit from a QMainWindow widget.
auto *quit = new QAction("&Quit", this);
This code line creates a QAction. Each QMenu has one or more action objects.
QMenu *file; file = menuBar()->addMenu("&File");
We create a QMenu object.
file->addAction(quit);
We put an action inside the menu using the addAction method.
connect(quit, &QAction::triggered, qApp, QApplication::quit);
When we select this option from the menu, the application quits.
main.cpp
#include “simple_menu.h”
int main(int argc, char *argv[]) {
QApplication app(argc, argv);
SimpleMenu window;
window.resize(350, 250); window.setWindowTitle(“Simple menu”); window.show();
return app.exec(); }
The main file.
Figure: Simple menu
Qt5 icons, shortcuts, and separators
In the following example, we further enhance our previous application. We add icons to the menus, use shortcuts and a separator.
another_menu.h
#pragma once
#include <QMainWindow> #include <QApplication>
class AnotherMenu : public QMainWindow {
public: AnotherMenu(QWidget *parent = nullptr); };
The header file for the example.
another_menu.cpp
#include <QMenu> #include <QMenuBar> #include “another_menu.h”
AnotherMenu::AnotherMenu(QWidget *parent) : QMainWindow(parent) {
QPixmap newpix(“new.png”); QPixmap openpix(“open.png”); QPixmap quitpix(“quit.png”);
auto *newa = new QAction(newpix, “&New”, this); auto *open = new QAction(openpix, “&Open”, this); auto *quit = new QAction(quitpix, “&Quit”, this); quit->setShortcut(tr(“CTRL+Q”));
QMenu *file = menuBar()->addMenu("&File"); file->addAction(newa); file->addAction(open); file->addSeparator(); file->addAction(quit);
qApp->setAttribute(Qt::AA_DontShowIconsInMenus, false);
connect(quit, &QAction::triggered, qApp, &QApplication::quit); }
In our example, we have one menu with three actions. Only the quit action will actually do something if we select it. We also create a separator and a CTRL+Q shortcut, which terminates the application.
QPixmap newpix(“new.png”); QPixmap openpix(“open.png”); QPixmap quitpix(“quit.png”);
These are images that we use in menus. Note that some desktop environments might not display images in the menus.
auto *newa = new QAction(newpix, “&New”, this); auto *open = new QAction(openpix, “&Open”, this); auto *quit = new QAction(quitpix, “&Quit”, this);
In this code we use the QAction constructor with a pixmap as the first argument.
quit->setShortcut(tr(“CTRL+Q”));
Here we create a keyboard shortcut. By pressing this shortcut, we run the quit action which will quit the application.
file->addSeparator();
We create a separator. The separator is a horizontal line which enables us to group menu actions into some logical groups.
qApp->setAttribute(Qt::AA_DontShowIconsInMenus, false);
In some environments, the menu icons are not shown by default. In this case we can disable the Qt::AA_DontShowIconsInMenus attribute.
main.cpp
#include “another_menu.h”
int main(int argc, char *argv[]) {
QApplication app(argc, argv);
AnotherMenu window;
window.resize(350, 250); window.setWindowTitle(“Another menu”); window.show();
return app.exec(); }
This is the main file.
Figure: Another menu example
Qt5 checkable menu
In the next example, we create a checkable menu. This will be an action with a check box. The option toggles the visibility of a statusbar.
checkable.h
#pragma once
#include <QMainWindow> #include <QApplication>
class Checkable : public QMainWindow {
Q_OBJECT
public: Checkable(QWidget *parent = nullptr);
private slots: void toggleStatusbar();
private: QAction *viewst; };
The header file for the example.
checkable.cpp
#include <QMenu> #include <QMenuBar> #include <QStatusBar> #include “checkable.h”
Checkable::Checkable(QWidget *parent) : QMainWindow(parent) {
viewst = new QAction("&View statusbar", this); viewst->setCheckable(true); viewst->setChecked(true);
QMenu *file = menuBar()->addMenu("&File"); file->addAction(viewst);
statusBar();
connect(viewst, &QAction::triggered, this, &Checkable::toggleStatusbar); }
void Checkable::toggleStatusbar() {
if (viewst->isChecked()) {
statusBar()->show();
} else {
statusBar()->hide();
} }
A checkable menu item toggles the visibility of the statusbar.
viewst = new QAction("&View statusbar", this); viewst->setCheckable(true); viewst->setChecked(true);
We create an action and make it checkable with the setCheckable method. The setChecked method makes it checked.
if (viewst->isChecked()) {
statusBar()->show();
} else {
statusBar()->hide();
}
Inside the toggleStatusbar method, we determine if the menu item is checked and hide or show the statusbar accordingly.
main.cpp
#include “checkable.h”
int main(int argc, char *argv[]) {
QApplication app(argc, argv);
Checkable window;
window.resize(350, 250); window.setWindowTitle(“Checkable menu”); window.show();
return app.exec(); }
This is the main file.
Figure: Checkable menu
Qt5 QToolBar
The QToolBar class provides a movable panel that contains a set of controls which provide a quick access to the application actions.
toolbar.h
#pragma once
#include <QMainWindow> #include <QApplication>
class Toolbar : public QMainWindow {
Q_OBJECT
public: Toolbar(QWidget *parent = nullptr); };
The header file for the example.
toolbar.cpp
#include <QToolBar> #include <QIcon> #include <QAction> #include “toolbar.h”
Toolbar::Toolbar(QWidget *parent) : QMainWindow(parent) {
QPixmap newpix(“new.png”); QPixmap openpix(“open.png”); QPixmap quitpix(“quit.png”);
QToolBar *toolbar = addToolBar(“main toolbar”); toolbar->addAction(QIcon(newpix), “New File”); toolbar->addAction(QIcon(openpix), “Open File”); toolbar->addSeparator();
QAction *quit = toolbar->addAction(QIcon(quitpix), “Quit Application”);
connect(quit, &QAction::triggered, qApp, &QApplication::quit); }
To create a toolbar, we inherit from the QMainWindow widget.
QToolBar *toolbar = addToolBar(“main toolbar”);
The addToolBar method creates a toolbar and returns a pointer to it.
toolbar->addAction(QIcon(newpix), “New File”); toolbar->addAction(QIcon(openpix), “Open File”); toolbar->addSeparator();
Here we add two actions and a separator to the toolbar.
main.cpp
#include “toolbar.h”
int main(int argc, char *argv[]) {
QApplication app(argc, argv);
Toolbar window;
window.resize(350, 250); window.setWindowTitle(“QToolBar”); window.show();
return app.exec(); }
This is the main file.
Figure: QToolBar
Qt5 aplication skeleton
In the end of this part of the C++ Qt5 tutorial, we create an application skeleton. The example is based mainly on the QMainWindow widget.
skeleton.h
#pragma once
#include <QMainWindow> #include <QApplication>
class Skeleton : public QMainWindow {
Q_OBJECT
public: Skeleton(QWidget *parent = nullptr); };
The header file for the example.
skeleton.cpp
#include <QToolBar> #include <QIcon> #include <QAction> #include <QMenu> #include <QMenuBar> #include <QStatusBar> #include <QTextEdit> #include “skeleton.h”
Skeleton::Skeleton(QWidget *parent) : QMainWindow(parent) {
QPixmap newpix(“new.png”); QPixmap openpix(“open.png”); QPixmap quitpix(“quit.png”);
auto *quit = new QAction("&Quit", this);
QMenu *file = menuBar()->addMenu("&File"); file->addAction(quit);
connect(quit, &QAction::triggered, qApp, &QApplication::quit);
QToolBar *toolbar = addToolBar(“main toolbar”); toolbar->addAction(QIcon(newpix), “New File”); toolbar->addAction(QIcon(openpix), “Open File”); toolbar->addSeparator();
QAction *quit2 = toolbar->addAction(QIcon(quitpix), “Quit Application”); connect(quit2, &QAction::triggered, qApp, &QApplication::quit);
auto *edit = new QTextEdit(this);
setCentralWidget(edit);
statusBar()->showMessage(“Ready”); }
Here we create a menu a toolbar and a statusbar.
auto *edit = new QTextEdit(this);
setCentralWidget(edit);
We create a QTextEdit widget and place it into the central part of the QMainWindow widget.
main.cpp
#include “skeleton.h”
int main(int argc, char *argv[]) {
QApplication app(argc, argv);
Skeleton window;
window.resize(450, 350); window.setWindowTitle(“Application skeleton”); window.show();
return app.exec(); }
This is the main file.
Figure: Application skeleton
In this part of the Qt5 tutorial, we have covered menus and toolbars.
