[PyQt] Newbe - QGraphicsScreen and QGraphicsView interaction problem

[stan]

I am creating an embedded application, and the versions I have to use
presently for Qt and PyQt do not support QGraphicsScene.addWidget().  I
want various scene/view items to be able to interact with others
scene/view items.  I have tried emitting signals from one item to
another, but have not had any success.  After having searched the
literature, posts, and google, I appreciate that this MIGHT not be
practicabl, so I would like to confirm this!  Can you advise me if there
is anyway to get the " intention" of the following code to work?  I
would like, for example, to effect an instance of a QGraphicstextItem
with its setPlainText() method  from another GraphicsItem event such as
from a reimplementation of its .mouseReleaseEvent method:

from PyQt4 import *
from PyQt4.QtGui import*
from PyQt4.QtCore import *
import sys

class text(QGraphicsTextItem):
	def __init__(self):
		QGraphicsTextItem.__init__(self)
		self.setFlag(QGraphicsItem.ItemIsFocusable)
		self.setFlag(QGraphicsItem.ItemIsSelectable)
		self.setTextInteractionFlags(Qt.TextEditable)
		self.setPlainText("0000")
		self.setZValue(3.0)

class marker(QGraphicsItem):
	def __init__(self):
		QGraphicsItem.__init__(self)
		self.setFlag(QGraphicsItem.ItemIsFocusable)
		self.setFlag(QGraphicsItem.ItemIsMovable)

	def boundingRect(self):
		return QRectF(25.0,0.0,25.0,270.0)

	def paint(self, painter, option, widget): 
		ss = painter.drawRect(25.0,230.0,25.0,25.0)
		tt = painter.drawLine(37.5,0.0,37.5,270.0)

	def mouseMoveEvent(self, mouseEvent):
		pt = self.mapToScene(mouseEvent.pos()).x()
		self.setPos(pt-37.5,0)
		self.update()

	def mouseReleaseEvent(self,mouseEvent1):
		dbl = text()
		dbl.setVisible(True)
		dbl.setPlainText("3.333")
		dbl.setFlag(QGraphicsItem.ItemIsFocusable)
		dbl.moveBy(50.0,50.0)
		dbl.update()

class MainScene(QGraphicsScene):
	def __init__(self):
		QGraphicsScene.__init__(self)
		self.setSceneRect(0.0,0.0,480,270)
		item,item1 = text(),marker()
		self.addItem(item),	self.addItem(item1)
		
class AllItemsView(QGraphicsView):
	def __init__(self):
		QGraphicsView.__init__(self)
		self.setWindowTitle("Text")
		self.setInteractive(True)
		self.setEnabled(True)
		self.scene = MainScene()
		self.mainScene = MainScene()
		self.setScene(self.mainScene)
		
if __name__=="__main__":
	app = QApplication(sys.argv)
	view = AllItemsView()	
	view.show()
	sys.exit(app.exec_())

The two items appear and work fine, but it is impossible to change the
contents of the text instance from the marker item.  Thanks for any
comments on this problem!