menubar problem, help me!!

[dungsivn]

I created a small application and subclass QMenubar, this class has a layout with some buttons, textedit,... In mainwindow class, I used setMenubar(..) to replace the system menubar by one.

Here is code:

// MainWindow is main class and called in main.cpp. This class contains toolbar, statusbar


void MainWindow::createMenus()
{
//....

setMenuBar(new MenuBar(this))
}



and here is constructor of MenuBar class:




MenuBar::MenuBar(QWidget* parent):QMenuBar(parent)
{

gridLayout = new QGridLayout(this);
gridLayout->setObjectName(QString::fromUtf8("gridLayout"));

hboxLayout = new QHBoxLayout();
hboxLayout->setObjectName(QString::fromUtf8("hboxLayout"));

toolButton = new QToolButton(this);
toolButton->setObjectName(QString::fromUtf8("toolButton"));

hboxLayout->addWidget(toolButton);

pushButton_2 = new QPushButton(this);
pushButton_2->setObjectName(QString::fromUtf8("pushButton_2"));

hboxLayout->addWidget(pushButton_2);

pushButton_3 = new QPushButton(this);
pushButton_3->setObjectName(QString::fromUtf8("pushButton_3"));

hboxLayout->addWidget(pushButton_3);

spacerItem = new QSpacerItem(40, 20, QSizePolicy::Expanding, QSizePolicy::Minimum);

hboxLayout->addItem(spacerItem);

lineEdit = new QLineEdit(this);
lineEdit->setObjectName(QString::fromUtf8("lineEdit"));

hboxLayout->addWidget(lineEdit);


setFixedHeight(50);

gridLayout->addLayout(hboxLayout, 0, 0, 1, 1);
this->setLayout(gridLayout);
this->show();

}



The problem is that: the toolbar of mainwindow is always above the subclass Menubar, hide the area of Menubar. I want the geometry of the toolbar is below the subclass Menubar.
Any help? thanks!

[jpn]

How does removing fixed height affect? I'd like to try, could you attach a compilable example?