How to add a Menu Bar into a Window Frame? [QT with C++]

问题

I'm a beginner in C++ and I started learning how to use QT components through code at MVS IDE. I still don't know if that was the best option to begin, but since I'm a java programmer, I made the path I made with Java (Swing components). So, my problem is, how to comunicate two class of my code, since in one I made the window frame and in the other I made my menu bar?

In java I would make something like:

JFrame frame = new JFrame();
JMenu menu = new JMenu();

frame.add(menu);

Anyway, This is my code:

#include "Header.h"

class MainWindow{

    private:

        QWidget *widget;

    public:

        void buildWindow(QApplication& app){

            widget = app.desktop();
            QMainWindow *main_window = new QMainWindow();
            QWidget *mainWid = new QWidget(main_window);
            MyMenuBar myMenuBar(mainWid);
            main_window->setWindowState(mainWid->windowState() | Qt::WindowMaximized);
            main_window->setWindowTitle("QT Trainning");
            main_window->show();            
        }

};

class MyMenuBar:QMainWindow {

    public:

    MyMenuBar(QWidget* mainWid){

         QAction *quit = new QAction("&Quit", this);

         QMenuBar *menu = new QMenuBar(mainWid);
         QMenu *file;

         menu->addMenu(file);
          file = menuBar()->addMenu("&File");
            file->addAction(quit);

          connect(quit, SIGNAL(triggered()), qApp, SLOT(quit()));
    }

};

int main(int argc, char *argv[])
{
   QApplication app(argc, argv);

   MainWindow frame;

   frame.buildWindow(app);

   return app.exec();
}

I tryed to create an Instance of MenuBar inside the Window class but wans't so helpfull and to be honest most of the materials I found to deal with QT interface they supose that you are using the QT GUI...Any tips about how to solve the problem or what should I really do to practice C++??

Thanks in advance

回答1:

You should specify access specifier for inheritance,otherwise default mode is public.

Also, if you are going to have all the classes in the same file the ordering is important(i think). In your case MyMenuBar should come before MainWindow. So, it is a better practice to have different components in different headers and then include them as necessary.

Here is the code for the case where you need two classes separately:

class TrainingMenu:public QMainWindow {

public:

        TrainingMenu(QMenuBar *menubar){
            QAction *quit = new QAction("&Quit", menubar);

            QMenu *file;

            file = menubar->addMenu("&File");
            file->addAction(quit);

            connect(quit, SIGNAL(triggered()), qApp, SLOT(quit()));
        }

};

class MainWindows:public QMainWindow{

private:
    TrainingMenu* _menu;
public:
    MainWindows(QMainWindow *parent = 0):QMainWindow(parent) {
        _menu=new TrainingMenu(MainWindows::menuBar()); 
        this->setWindowTitle("Qt training");
        this->setWindowState(Qt::WindowMaximized);
        this->show();
    }

};



int main(int argc, char *argv[])
{
   QApplication app(argc, argv);
   MainWindows window;

   return app.exec();
}

回答2:

This example should be good enough. You do the following:

Create a QMenu with the top widget as a parent
Add submenu QMenu instances to the root level menu

来源：https://stackoverflow.com/questions/19141724/how-to-add-a-menu-bar-into-a-window-frame-qt-with-c

标签

c++

components

add