PyQt4 QGraphicsView and 'pressed' signal

[splondike]

Thanks for your reply. In my actual application i'm trying to use signals/slots to combine the functions dealing with remapping the QGraphicsView drag button from left to middle. The following is the relevant code i've lifted from my application:

#TODO: Make signals work properly
def mousePressEvent(self, event):
	self.emit(SIGNAL("pressed"), (event))
	QtGui.QGraphicsView.mousePressEvent(self, event)
def mouseReleaseEvent(self, event):
	self.emit(SIGNAL("released"), (event))
	QtGui.QGraphicsView.mouseReleaseEvent(self, event)
######
 
#Assigned via self.connect(self, SIGNAL('pressed'), self.grabCanvas) in __init__
def grabCanvas(self, event):
	if event.buttons() == QtCore.Qt.MidButton:
		origMode = self.dragMode()
		self.setDragMode(self.ScrollHandDrag)
		#Send a fake LMB press, TODO: Disable scene's selection of objects
		fake_event = QtGui.QMouseEvent(QtCore.QEvent.MouseButtonPress, event.pos(), 
				QtCore.Qt.LeftButton, QtCore.Qt.LeftButton, QtCore.Qt.KeyboardModifiers())
		QtGui.QGraphicsView.mousePressEvent(self, fake_event)
 
		#Add a handler to catch the mouse up event
		def revert(event):
			self.setDragMode(origMode)
			self.disconnect(self, SIGNAL("released"), revert)
 
		self.connect(self, SIGNAL("released"), revert)

#TODO: Make signals work properly
def mousePressEvent(self, event):
	self.emit(SIGNAL("pressed"), (event))
	QtGui.QGraphicsView.mousePressEvent(self, event)
def mouseReleaseEvent(self, event):
	self.emit(SIGNAL("released"), (event))
	QtGui.QGraphicsView.mouseReleaseEvent(self, event)
######

#Assigned via self.connect(self, SIGNAL('pressed'), self.grabCanvas) in __init__
def grabCanvas(self, event):
	if event.buttons() == QtCore.Qt.MidButton:
		origMode = self.dragMode()
		self.setDragMode(self.ScrollHandDrag)
		#Send a fake LMB press, TODO: Disable scene's selection of objects
		fake_event = QtGui.QMouseEvent(QtCore.QEvent.MouseButtonPress, event.pos(), 
				QtCore.Qt.LeftButton, QtCore.Qt.LeftButton, QtCore.Qt.KeyboardModifiers())
		QtGui.QGraphicsView.mousePressEvent(self, fake_event)

		#Add a handler to catch the mouse up event
		def revert(event):
			self.setDragMode(origMode)
			self.disconnect(self, SIGNAL("released"), revert)
		
		self.connect(self, SIGNAL("released"), revert)

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As you can perhaps see, i'm trying to make a temporary slot to reset some parameters when the button is released. I felt the most elegant and unobtrusive way of doing this would be using signals/slots rather than two event listeners and a bunch of shared flags (like middleButtonPressed, originalDragMode etc.).