PyQT: QListWidgetItem defined on Dialog window cannot be access from Main Window

Question

I've designed a UI using PyQT, and defined two windows (Main and Dialog). The idea is to define on the MainWindow several buttons and when you press on this it´s open a detail window with a list. I'm assuming that there's nothing wrong with the code created by pyuic4, but anyway I'll put the code of the Detail Window where you can see the list defined:

from PyQt4 import QtCore, QtGui

try:
    _fromUtf8 = QtCore.QString.fromUtf8
except AttributeError:
    def _fromUtf8(s):
        return s

try:
    _encoding = QtGui.QApplication.UnicodeUTF8
    def _translate(context, text, disambig):
        return QtGui.QApplication.translate(context, text, disambig, _encoding)
except AttributeError:
    def _translate(context, text, disambig):
        return QtGui.QApplication.translate(context, text, disambig)

class Ui_DetailWindow(object):
    def setupUi(self, DetailWindow):
        DetailWindow.setObjectName(_fromUtf8("DetailWindow"))
        DetailWindow.setWindowModality(QtCore.Qt.NonModal)
        DetailWindow.setEnabled(True)
        DetailWindow.resize(600, 650)
        DetailWindow.setLocale(QtCore.QLocale(QtCore.QLocale.English,     QtCore.QLocale.UnitedStates))
        self.btnClose = QtGui.QPushButton(DetailWindow)
        self.btnClose.setEnabled(True)
        self.btnClose.setGeometry(QtCore.QRect(480, 610, 110, 32))
        self.btnClose.setObjectName(_fromUtf8("btnClose"))
        self.label = QtGui.QLabel(DetailWindow)
        self.label.setGeometry(QtCore.QRect(20, 20, 111, 20))
        self.label.setObjectName(_fromUtf8("label"))
        self.listAlarmsActive = QtGui.QListWidget(DetailWindow)
        self.listAlarmsActive.setGeometry(QtCore.QRect(10, 50, 256, 192))
        self.listAlarmsActive.setObjectName(_fromUtf8("listAlarmsActive"))

        self.retranslateUi(DetailWindow)
        QtCore.QMetaObject.connectSlotsByName(DetailWindow)

    def retranslateUi(self, DetailWindow):
        DetailWindow.setWindowTitle(_translate("DetailWindow", "Details", None))
        self.btnClose.setText(_translate("DetailWindow", "Close", None))
        self.label.setText(_translate("DetailWindow", "Alarms activated", None))

So, in the main code I define the class of the Detail window in this way:

class Detail(QtGui.QDialog):
    def __init__(self):
        QtGui.QDialog.__init__(self)       
        self.ventanaDet = Ui_DetailWindow()
        self.ventanaDet.setupUi(self)        
        self.connect(self.ventanaDet.btnClose, QtCore.SIGNAL('clicked()'), QtCore.SLOT('close()'))

So, in the constructor for the MainWindow, I do this:

class Principal(QtGui.QMainWindow):
    def __init__(self):
        QtGui.QMainWindow.__init__(self)

        self.ventana = Ui_MainWindow()
        self.ventana.setupUi(self)

        self.connect(self.ventana.btnExit, QtCore.SIGNAL('clicked()'), QtCore.SLOT('close()'))
        self.ventana.btnHvac.clicked.connect(self.showDetailHvac)
        self.ventana.btnCryo.clicked.connect(self.showDetailCryo)
        self.ventanaDet = None

    def showDetailHvac(self):
        if self.ventanaDet is None:
            self.ventanaDet = Detail()
        self.ventanaDet.setWindowTitle("HVAC Alarms Detail")
        alarmsHvac=[]
        alarmsHvac.append("HVAC Alarm1")
        alarmsHvac.append("HVAC Alarm2")
        for alarm in alarmsHvac:
            row=0
            listItem=QtGui.QListWidgetItem(alarm);
            self.ventanaDet.listAlarmsActive.insertItem(row,listItem)
            row=row+1
        self.ventanaDet.show() 

This is the error I get on the console:

Traceback (most recent call last):
  File "./aogAlarmPanel.py", line 37, in showDetailHvac
    self.ventanaDet.listAlarmsActive.insertItem(row,listItem)
AttributeError: 'Detail' object has no attribute 'listAlarmsActive'

When I change the constructor (only for test purposes) and I put the data on it, it works fine, but is not the idea:

class Detail(QtGui.QDialog):
    def __init__(self):
        QtGui.QDialog.__init__(self)

        self.ventanaDet = Ui_DetailWindow()
        self.ventanaDet.setupUi(self)

        alarmsHvac=[]
        alarmsHvac.append("HVAC Alarm1")
        alarmsHvac.append("HVAC Alarm2")
        for alarm in alarmsHvac:
            row=0
            listItem=QtGui.QListWidgetItem(alarm);
            self.ventanaDet.listAlarmsActive.insertItem(row,listItem)
            row=row+1

        self.connect(self.ventanaDet.btnClose, QtCore.SIGNAL('clicked()'), QtCore.SLOT('close()'))

Can you help me please? I'm guessing that I have a huge error on the definitions of the windows, but I cannot find it. Thanks in advance.

Answer 1

You have made a very silly mistake here. You need to change:- self.ventanaDet.listAlarmsActive.insertItem(row,listItem) to self.ventanaDet.ventanaDet.listAlarmsActive.insertItem(row,listItem).

You may have figured out whats wrong but still a small description of the bug is as:- self.ventanaDet is initialized with Details and there is yet another variable ventanaDet in Details which is actually initialized with Ui_DetailWindow.