QMdiArea shows incorrectly

Question

I have a problem when using QMdiArea in PyQt5, the following is what I have done:

1. I create a demo UI with Qt designer, looks like:

2. When I preview it in Qt designer, it looks OK:

3. However, when I use pyqt5_uic to convert the .ui file to .py file, and run the code, it looks like this:

I found that the corresponding .py code generate with uic tools fails to set parent for subwindows in mdiarea:

self.mdiArea = QtWidgets.QMdiArea(IOWidgets)
        self.mdiArea.setGeometry(QtCore.QRect(555, 120, 421, 181))
        self.mdiArea.setObjectName("mdiArea")
        self.subwindow = QtWidgets.QWidget()
        self.subwindow.setObjectName("subwindow")
        self.lineEdit_1_IO = QtWidgets.QLineEdit(self.subwindow)
        self.lineEdit_1_IO.setGeometry(QtCore.QRect(20, 20, 61, 21))
        self.lineEdit_1_IO.setObjectName("lineEdit_1_IO")
        self.spinBox_1_IO = QtWidgets.QSpinBox(self.subwindow)
        self.spinBox_1_IO.setGeometry(QtCore.QRect(30, 60, 42, 22))
        self.spinBox_1_IO.setObjectName("spinBox_1_IO")

if I change the critical line code to:

self.subwindow = QtWidgets.QWidget(self.mdiArea)

then I can see the subwindow in mdiarea, but it looks strange:

---

here is simple demo:

1. the .py code generate with uic tools is Ui_Mdi_simple.py:

from PyQt5 import QtCore, QtGui, QtWidgets


class Ui_MDI_test(object):
    def setupUi(self, MDI_test):
        MDI_test.setObjectName("MDI_test")
        MDI_test.resize(545, 336)
        self.mdiArea = QtWidgets.QMdiArea(MDI_test)
        self.mdiArea.setGeometry(QtCore.QRect(70, 50, 331, 221))
        self.mdiArea.setObjectName("mdiArea")
        self.subwindow = QtWidgets.QWidget()
        self.subwindow.setObjectName("subwindow")
        self.comboBox = QtWidgets.QComboBox(self.subwindow)
        self.comboBox.setGeometry(QtCore.QRect(50, 30, 68, 22))
        self.comboBox.setObjectName("comboBox")
        self.lineEdit = QtWidgets.QLineEdit(self.subwindow)
        self.lineEdit.setGeometry(QtCore.QRect(50, 70, 113, 20))
        self.lineEdit.setObjectName("lineEdit")
        self.radioButton = QtWidgets.QRadioButton(self.subwindow)
        self.radioButton.setGeometry(QtCore.QRect(50, 110, 95, 20))
        self.radioButton.setObjectName("radioButton")
        self.subwindow_2 = QtWidgets.QWidget()
        self.subwindow_2.setObjectName("subwindow_2")

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

    def retranslateUi(self, MDI_test):
        _translate = QtCore.QCoreApplication.translate
        MDI_test.setWindowTitle(_translate("MDI_test", "Form"))
        self.subwindow.setWindowTitle(_translate("MDI_test", "subwindow_1"))
        self.radioButton.setText(_translate("MDI_test", "RadioButton"))
        self.subwindow_2.setWindowTitle(_translate("MDI_test", "subwindow_2"))

2. the main code is:

import sys
from PyQt5.QtWidgets import QWidget, QApplication
from Ui_Mdi_simple import Ui_MDI_test


class MDI_demo(QWidget, Ui_MDI_test):
    def __init__(self):
        super().__init__()
        self.setupUi(self)


if __name__ == "__main__":
    app = QApplication(sys.argv)
    win = MDI_demo()
    win.show()
    sys.exit(app.exec_())

the results turns out to be:

Answer 1

I found adding the following two lines of codes in Ui_MDI_test solves the problem:

self.mdiArea.addSubWindow(self.subwindow)
self.mdiArea.addSubWindow(self.subwindow_2)

@ eyllanesc, thanks.