What happens with QMainWindow

Question

I want to create the GUI with this code. When i click Add New Object Button, it will show the pop up (I use QMainWindown) but i want to put the QLabel in here, it can not work

I dont know why.i hope everyone can give me more some advices. Thanks you

This is my code :

from PySide import QtCore, QtGui
import sys

app = QtGui.QApplication.instance()
if not app:
    app = QtGui.QApplication([])

class Window(QtGui.QDialog):
    def __init__(self, parent=None):
        super(Window, self).__init__(parent)

        self.mainLayout = QtGui.QGridLayout()
        self.mainLayout.addWidget(self.First(), 0, 0, 2, 0)
        self.setLayout(self.mainLayout)
        self.setWindowTitle("Library")
        self.resize(700,660)
    #----------------------------------------FIRST COLUMN-------------------------------------
    def First(self):
        FirstFrame = QtGui.QFrame()
        FirstFrame.setFixedSize(230,700)

    # LABEL
        renderer_lb  = QtGui.QLabel("Renderer :")
        folders_lb = QtGui.QLabel("Folder :")
    #COMBOBOX
        self.renderer_cbx = QtGui.QComboBox()
        self.renderer_cbx.addItem("Vray")
        self.renderer_cbx.addItem("Octane")
    # LIST VIEW FOLDER
        self.folders_lv = QtGui.QListView()
    # BUTTON
        addnewobject_btn = QtGui.QPushButton("Add New Objects")
        newset_btn = QtGui.QPushButton("New Set")

    # DEFINE THE FUNCTION FOR FIRST FRAME
        Firstbox = QtGui.QGridLayout()
        Firstbox.addWidget(renderer_lb,0,0)
        Firstbox.addWidget(folders_lb,2,0,1,4)
        Firstbox.addWidget(self.renderer_cbx,0,1,1,3)
        Firstbox.addWidget(self.folders_lv,3,0,1,4)
        Firstbox.addWidget(addnewobject_btn,4,0,1,2)
        Firstbox.addWidget(newset_btn,4,3)
        Firstbox.setColumnStretch(1, 1)
        FirstFrame.setLayout(Firstbox)

        addnewobject_btn.clicked.connect(self.addnewobject)

        return FirstFrame

    def addnewobject(self):
        window = QtGui.QMainWindow(self)
        window.setWindowTitle('Select folder of new objects')
        window.setFixedSize(450,90)
        window.show()

        folder_lb = QtGui.QLabel("Folder : ")

        browser = QtGui.QGridLayout()
        browser.addWidget(folder_lb,0,0)
        window.setLayout(browser)

if __name__ == '__main__':
    window = Window()
    sys.exit(window.exec_())

Answer 1

Just as you did in the First() function, you could create an homemade widget using QFrame . Then you can set a central widget for your new window.

from PySide import QtCore, QtGui
import sys

app = QtGui.QApplication.instance()
if not app:
    app = QtGui.QApplication([])

class Window(QtGui.QDialog):
    def __init__(self, parent=None):
        super(Window, self).__init__(parent)

        self.mainLayout = QtGui.QGridLayout()
        self.mainLayout.addWidget(self.First(), 0, 0, 2, 0)
        self.setLayout(self.mainLayout)
        self.setWindowTitle("Library")
        self.resize(700,660)
        self.show()
    #----------------------------------------FIRST COLUMN-------------------------------------
    def First(self):
        FirstFrame = QtGui.QFrame()
        FirstFrame.setFixedSize(230,700)

    # LABEL
        renderer_lb  = QtGui.QLabel("Renderer :")
        folders_lb = QtGui.QLabel("Folder :")
    #COMBOBOX
        self.renderer_cbx = QtGui.QComboBox()
        self.renderer_cbx.addItem("Vray")
        self.renderer_cbx.addItem("Octane")
    # LIST VIEW FOLDER
        self.folders_lv = QtGui.QListView()
    # BUTTON
        addnewobject_btn = QtGui.QPushButton("Add New Objects")
        newset_btn = QtGui.QPushButton("New Set")

    # DEFINE THE FUNCTION FOR FIRST FRAME
        Firstbox = QtGui.QGridLayout()
        Firstbox.addWidget(renderer_lb,0,0)
        Firstbox.addWidget(folders_lb,2,0,1,4)
        Firstbox.addWidget(self.renderer_cbx,0,1,1,3)
        Firstbox.addWidget(self.folders_lv,3,0,1,4)
        Firstbox.addWidget(addnewobject_btn,4,0,1,2)
        Firstbox.addWidget(newset_btn,4,3)
        Firstbox.setColumnStretch(1, 1)
        FirstFrame.setLayout(Firstbox)

        addnewobject_btn.clicked.connect(self.addnewobject)

        return FirstFrame

    def addnewobject(self):
        secondFrame = QtGui.QFrame()
        secondFrame.setFixedSize(230,700)
    # LABEL
        folders_lb = QtGui.QLabel("Folder :")

    # DEFINE THE FUNCTION FOR FIRST FRAME
        secondGridLayout = QtGui.QGridLayout()
        secondGridLayout.addWidget(folders_lb,2,0,1,4)
        secondGridLayout.setColumnStretch(1, 1)
        secondFrame.setLayout(secondGridLayout)

        window = QtGui.QMainWindow(self)
        window.setWindowTitle('Select folder of new objects')
        window.setFixedSize(600,700)

        window.setCentralWidget(secondFrame) # Here is the main change: setLayout(QLayout) to setCentralWidget(QWidget)
        window.show()

if __name__ == '__main__':
    window = Window()
    sys.exit(window.exec_())

Is this intended for Maya? If yes, I recommand you not to use modal windows as it will quickly fed up the users.