Modify listbox from another class with pyqt

Question

I'm doing a GUI for a database through PyQt and Python. The main window (class Window) has a listbox where I put all my data, for this example I put "The program is working". Furthermore, The other window (class AddWin) help me to add new costumers to the database, but I couldn't modify the listbox from the class Addwin. I have the following code in my program and I would like to clean the listbox from the class AddWin, can you help me? or what is my mistake in the following code?

class Window(QtGui.QMainWindow):
    def __init__(self, parent=None):
        QtGui.QMainWindow.__init__(self, parent)
        #Listbox 
        self.lista = QtGui.QListWidget(self)
        self.lista.move(155,221)
        self.lista.resize(855,455)
        self.lista.addItem("The program is working")

class AddWin(QtGui.QDialog):
    def __init__(self, parent=None):
        QtGui.QDialog.__init__(self, parent)
        main = Window()
        main.lista.clear()

if __name__ == '__main__':

    import sys
    app = QtGui.QApplication(sys.argv)
    window = Window()
    window.show()
    sys.exit(app.exec_())

Answer 1

Your mistake is that code doesn't instantiate AddWin anywhere, so lista.clear is never called.

Your can test it by changing

window = Window()

to

window = AddWin()

---

LAST EDITED 21 / 8 / 2014 12 : 42

If your want to shard QtGui.QListWidget from QtGui.QMainWindow to QtGui.QDialog, Your can use pass value by reference to QtGui.QDialog.

Assume your QtGui.QMainWindow must have QtGui.QDialog (Or AddWin);

class Window(QtGui.QMainWindow):
    def __init__(self, parent=None):
        QtGui.QMainWindow.__init__(self, parent)
        #Listbox 
        self.lista = QtGui.QListWidget(self)
        self.lista.move(155,221)
        self.lista.resize(855,455)
        self.lista.addItem("The program is working")
        self.myAddWin = AddWin(self.lista, self) # <- Pass QListWidget to your class

class AddWin(QtGui.QDialog):
    def __init__(self, refQListWidget, parent=None):
        QtGui.QDialog.__init__(self, parent)
        self.myRefQListWidget = refQListWidget
        self.myRefQListWidget.clear()