In QMainWindow invoke another QMainWindow using pyqt4 in python?

Question

I am using version python 2.7 and use pyqt4 for GUI programming in python. I want to call from Ui_MainWindow1 to Ui_MainWindow2.Here is code:

Class Ui_MainWindow1

class Ui_MainWindow1(object):
    def setupUi(self, MainWindow):
        ...
        ...
        self.pushButton = QtGui.QPushButton(self.centralwidget)
        self.pushButton.setGeometry(QtCore.QRect(70, 90, 181, 27))
        self.pushButton.setObjectName(_fromUtf8("pushButton"))
        MainWindow.setCentralWidget(self.centralwidget)
        ...
        QtCore.QObject.connect(self.pushButton, QtCore.SIGNAL("clicked()"),self.callSecondWindow)
    def callSecondWindow(self):
        MainWindow2 = QtGui.QMainWindow()
        ui = Ui_MainWindow2()
        ui.setupUi(MainWindow2)
        MainWindow2.show()
if __name__ == "__main__":
    import sys
    app = QtGui.QApplication(sys.argv)
    MainWindow = QtGui.QMainWindow()
    ui = Ui_MainWindow1()
    ui.setupUi(MainWindow)
    MainWindow.show()
    sys.exit(app.exec_())

Ui_MainWindow2

class Ui_MainWindow2(object):
    def setupUi(self, MainWindow):
        MainWindow.setObjectName(_fromUtf8("MainWindow"))
        MainWindow.resize(336, 277)
        self.centralwidget = QtGui.QWidget(MainWindow)
        self.centralwidget.setObjectName(_fromUtf8("centralwidget"))
        self.label = QtGui.QLabel(self.centralwidget)
        self.label.setGeometry(QtCore.QRect(110, 70, 131, 51))
        font = QtGui.QFont()
        ...
        ...

When I click on pushButton in Ui_MainWindow1.It's not showing another GUI(Ui_MainWindow2) and without giving any error.

How to sort this out? Need Help!

Answer 1

That looks messy. This is a more common way to write something like this:

from PyQt4 import QtGui
from PyQt4.uic.properties import QtCore

class MainWindow1(QtGui.QMainWindow):
    def __init__(self, *args, **kwargs):
        super(MainWindow1, self).__init__(*args, **kwargs)

        self.pushButton = QtGui.QPushButton('pushButton')
        self.pushButton.released.connect(self.callSecondWindow)
        self.mainWindow2 = MainWindow2()

        self.setCentralWidget(self.pushButton)

    def callSecondWindow(self):
        self.mainWindow2.show()

class MainWindow2(QtGui.QMainWindow):
    def __init__(self, *args, **kwargs):
        super(MainWindow2, self).__init__(*args, **kwargs)
        self.resize(336, 227)
        self.setObjectName('centralwidget')
        self.label = QtGui.QLabel()

if __name__ == "__main__":
    import sys
    app = QtGui.QApplication(sys.argv)
    mainWindow = MainWindow1()
    mainWindow.show()
    sys.exit(app.exec_())

A few notes:

• there is no need for a setupUi function python already has __init__ for that

• the Signal syntax: QtCore.QObject.connect(self.pushButton, QtCore.SIGNAL("clicked()"),self.callSecondWindow)

• has been replaced by the more readable: self.pushButton.released.connect(self.callSecondWindow)

• there is usually no reason to hold an instance of QMainWindow inside of an extra object, just subclass it directly

• most people use lower case-names for variables, and upper-case names for classes, it's just a convention, but it makes the code more readable for others