Window 1 - > main window of the application (27)

window 1 -> The main window of the application （27）

The main window is the first window displayed after the application starts
QMainWindow The menu bar is encapsulated in , The toolbar , Central components , Docking components , Status bar and other components

There are many options after clicking the menu .

The whole program consists of a main window and several dialog boxes .

Menu Bar
Toolbars
Dock Widgets
Central Widget

menu bar （QMenuBar）
Drop down menu group （QMenu）
A menu item （QAction）

---

MainWindow::MainWindow()
{

}

MainWindow* MainWindow::NewInstance()
{
    MainWindow* ret = new MainWindow();

    if( (ret == NULL) || !ret->construct() )
    {
        delete ret;
        ret = NULL;
    }

    return ret;
}

bool MainWindow::construct()
{
    bool ret = true;

    ret = ret && initMenuBar();

    return ret;
}

bool MainWindow::initMenuBar()
{
    bool ret = true;
    QMenuBar* mb = menuBar();

    ret = ret && initFileMenu(mb);

    return ret;
}

bool MainWindow::initFileMenu(QMenuBar* mb)
{
    QMenu* menu = new QMenu("File(&F)");
    bool ret = (menu != NULL);

    if (ret) {
        QAction* action = NULL;

        ret = ret && makeAction(action, "New(N)", Qt::CTRL + Qt::Key_N);

        if( ret )
        {
            menu->addAction(action);    // add Action item to Menu
        }

        menu->addSeparator();

        ret = ret && makeAction(action, "Exit(X)", Qt::CTRL + Qt::Key_X);

        if(ret) 
        {
            menu->addAction(action);    // add Action item to Menu
        }
    }

    if( ret )
    {
        mb->addMenu(menu);    // add Menu add to application Menu Bar
    }
    else
    {
        delete menu;
    }


    return ret;
}

bool MainWindow::makeAction(QAction*& action, QString text, int key)
{
    bool ret = true;

    action = new QAction(text, NULL);

    if( action != NULL )
    {
        action->setShortcut(QKeySequence(key));
    }
    else
    {
        ret = false;
    }

    return ret;
}

MainWindow::~MainWindow()
{
    
}