PySide and QGraphics, how to make a simple window with widgets?

[JonnyPython]

Hi,
I want to write a simple QGraphics based browser. I did one with "none-QGraphic" widgets, and it worked create. But i got some problems with QGraphics.
Here is the code:

@
import sys
from PySide import QtGui, QtCore

class FirstClass(QtGui.QMainWindow):

def __init__(self):
    super(FirstClass, self).__init__()
    self.startingUI()


def startingUI(self):

    self.setWindowTitle('Hauptfenster')
    self.resize(800, 600)
    menue = self.menuBar()
    self.statusBar()
    menuleiste_datei = menue.addMenu('File')


    self.mainWidget = QtGui.QGraphicsWidget()
    self.scene = QtGui.QGraphicsScene(self)

    self.url_input = QtGui.QLineEdit()
    self.layout = QtGui.QGraphicsLinearLayout()
    self.scene.addWidget(self.url_input)
    self.mainWidget.setLayout(self.layout)

    self.view = QtGui.QGraphicsView()
    self.setCentralWidget(self.view)


    self.view.show()

    self.show()

def main():

app = QtGui.QApplication(sys.argv)
start = FirstClass()
sys.exit(app.exec_())

if name== 'main':
main()

@

I want to create a simple interface with a menubar, statusbar, a line input in which i can enter a url and then load it. All the new widgets i add dont get displayed. And i total don't understand the logic behind this.
The first thing i have to do is to create a QtGui.QGraphicsWidget() right? And since my class inherits from QtGui.QMainWindow, that GraphicWidget is somehow imbedded into the QMainWindow? And what is the relation to all this with the QtGui.QGraphicsView ? Do i even use the right widgets?