Adding a widget to a layout created from .ui file

Question

I am creating a GUI in Python using PySide2, this is my .ui file:

<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
 <class>main_window</class>
 <widget class="QWidget" name="main_window">
 <property name="windowModality">
 <enum>Qt::NonModal</enum>
 </property>
 <property name="enabled">
 <bool>true</bool>
 </property>
 <property name="geometry">
 <rect>
 <x>0</x>
 <y>0</y>
 <width>1000</width>
 <height>640</height>
 </rect>
 </property>
 <property name="windowTitle">
 <string>Testing App</string>
 </property>
 <layout class="QVBoxLayout" name="layout">
 <item>
 <layout class="QVBoxLayout" name="other_layout">
 <item>
 <widget class="QWidget" name="panel" native="true">
 <layout class="QHBoxLayout" name="layout3">
 <item>
 <layout class="QVBoxLayout" name="layout4">
 <item>
 <layout class="QHBoxLayout" name="layout5">
 <item>
 <widget class="QLabel" name="lo">
 <property name="text">
 <string>X</string>
 </property>
 <property name="alignment">
 <set>Qt::AlignCenter</set>
 </property>
 </widget>
 </item>
 <item>
 <widget class="QLineEdit" name="resolution_x">
 <property name="sizePolicy">
 <sizepolicy hsizetype="Preferred" vsizetype="Fixed">
 <horstretch>0</horstretch>
 <verstretch>0</verstretch>
 </sizepolicy>
 </property>
 <property name="inputMethodHints">
 <set>Qt::ImhDigitsOnly</set>
 </property>
 <property name="text">
 <string>175</string>
 </property>
 </widget>
 </item>
 </layout>
 </item>
 <item>
 <layout class="QHBoxLayout" name="layout6">
 <item>
 <widget class="QLabel" name="lo2">
 <property name="text">
 <string>Y</string>
 </property>
 <property name="alignment">
 <set>Qt::AlignCenter</set>
 </property>
 </widget>
 </item>
 <item>
 <widget class="QLineEdit" name="res2">
 <property name="sizePolicy">
 <sizepolicy hsizetype="Preferred" vsizetype="Fixed">
 <horstretch>0</horstretch>
 <verstretch>0</verstretch>
 </sizepolicy>
 </property>
 <property name="inputMethodHints">
 <set>Qt::ImhDigitsOnly</set>
 </property>
 <property name="text">
 <string>150</string>
 </property>
 </widget>
 </item>
 </layout>
 </item>
 </layout>
 </item>
 <item>
 <layout class="QVBoxLayout" name="layout7">
 <item>
 <layout class="QHBoxLayout" name="iterations_layout">
 <item>
 <widget class="QLabel" name="iterLab">
 <property name="text">
 <string>Num Passes</string>
 </property>
 <property name="alignment">
 <set>Qt::AlignCenter</set>
 </property>
 </widget>
 </item>
 <item>
 <widget class="QLineEdit" name="itr">
 <property name="sizePolicy">
 <sizepolicy hsizetype="Preferred" vsizetype="Fixed">
 <horstretch>0</horstretch>
 <verstretch>0</verstretch>
 </sizepolicy>
 </property>
 <property name="inputMethodHints">
 <set>Qt::ImhDigitsOnly</set>
 </property>
 <property name="text">
 <string>20</string>
 </property>
 </widget>
 </item>
 </layout>
 </item>
 <item>
 <layout class="QHBoxLayout" name="layout8">
 <item>
 <widget class="QPushButton" name="reset_button">
 <property name="sizePolicy">
 <sizepolicy hsizetype="Maximum" vsizetype="Fixed">
 <horstretch>0</horstretch>
 <verstretch>0</verstretch>
 </sizepolicy>
 </property>
 <property name="minimumSize">
 <size>
 <width>50</width>
 <height>0</height>
 </size>
 </property>
 <property name="layoutDirection">
 <enum>Qt::LeftToRight</enum>
 </property>
 <property name="text">
 <string>Zoom</string>
 </property>
 </widget>
 </item>
 </layout>
 </item>
 </layout>
 </item>
 </layout>
 </widget>
 </item>
 <item>
 <layout class="QHBoxLayout" name="process_layout">
 <item alignment="Qt::AlignLeft">
 <widget class="QLabel" name="status">
 <property name="sizePolicy">
 <sizepolicy hsizetype="Fixed" vsizetype="Fixed">
 <horstretch>0</horstretch>
 <verstretch>0</verstretch>
 </sizepolicy>
 </property>
 <property name="minimumSize">
 <size>
 <width>120</width>
 <height>20</height>
 </size>
 </property>
 <property name="maximumSize">
 <size>
 <width>120</width>
 <height>20</height>
 </size>
 </property>
 <property name="text">
 <string/>
 </property>
 <property name="alignment">
 <set>Qt::AlignCenter</set>
 </property>
 </widget>
 </item>
 <item alignment="Qt::AlignRight">
 <widget class="QLabel" name="procLab">
 <property name="minimumSize">
 <size>
 <width>77</width>
 <height>20</height>
 </size>
 </property>
 <property name="maximumSize">
 <size>
 <width>77</width>
 <height>20</height>
 </size>
 </property>
 <property name="text">
 <string>#</string>
 </property>
 </widget>
 </item>
 <item alignment="Qt::AlignRight">
 <widget class="QLineEdit" name="processes">
 <property name="sizePolicy">
 <sizepolicy hsizetype="Maximum" vsizetype="Fixed">
 <horstretch>0</horstretch>
 <verstretch>0</verstretch>
 </sizepolicy>
 </property>
 <property name="minimumSize">
 <size>
 <width>50</width>
 <height>0</height>
 </size>
 </property>
 <property name="maximumSize">
 <size>
 <width>50</width>
 <height>2000</height>
 </size>
 </property>
 <property name="inputMethodHints">
 <set>Qt::ImhDigitsOnly</set>
 </property>
 <property name="text">
 <string>8</string>
 </property>
 </widget>
 </item>
 </layout>
 </item>
 </layout>
 </item>
 </layout>
 </widget>
 <resources/>
 <connections/>
</ui>

I want to add a widget dynamically from my Python script to the main layout ('layout'):

app = QApplication(sys.argv)
f = MyWindow()
sys.exit(app.exec_())
class MyWindow(QWidget):
 def __init__(self):
 super(MyWindow, self).__init__(None)
 ui_file = QtCore.QFile("./myui.ui")
 ui_file.open(QtCore.QFile.ReadOnly)
 loader = QtUiTools.QUiLoader()
 self.window = loader.load(ui_file)
 ui_file.close()
 self.layout.addWidget(QLabel('Stuff'))
 self.window.show()

However, I get the following error

 self.layout.addWidget(QLabel('Stuff'))
AttributeError: 'builtin_function_or_method' object has no attribute 'addWidget'

I don't understand why self.layout doesn't have the property addWidget. I thought self.layout would have a reference to a QVBoxLayout object?

• Pablo: added more of the .ui file
• Pablo: @eyllanesc added it

Answer 1

You have several errors:

• The widget loaded from the .ui is not the MyWindow, on the other hand in PySide2 it is not possible to load a .ui to a widget class implemented by python (in PyQt5 if possible via uic.loadUi()) so the class should handle the widget.

• On the other hand, do not use variable names that may conflict with the names of the methods, for example the QWidget class has a layout method so it is not recommended that you have an attribute with that name, a possible solution is to use findChild to get the layout:

import sys
from PySide2.QtCore import QObject, QFile
from PySide2.QtWidgets import QApplication, QLabel, QVBoxLayout, QWidget
from PySide2.QtUiTools import QUiLoader
class Manager(QObject):
 def __init__(self):
 super(Manager, self).__init__(None)
 ui_file = QFile("./myui.ui")
 ui_file.open(QFile.ReadOnly)
 loader = QUiLoader()
 self.window = loader.load(ui_file)
 ui_file.close()
 lay = self.window.findChild(QVBoxLayout, "layout")
 lay.addWidget(QLabel("Stuff"))
 self.window.show()
if __name__ == "__main__":
 app = QApplication(sys.argv)
 f = Manager()
 sys.exit(app.exec_())

• Another possible solution is to change the name of the layout to for example vlayout: <layout class="QVBoxLayout" name="vlayout">

import sys
from PySide2.QtCore import QObject, QFile
from PySide2.QtWidgets import QApplication, QLabel, QWidget
from PySide2.QtUiTools import QUiLoader
class Manager(QObject):
 def __init__(self):
 super(Manager, self).__init__(None)
 ui_file = QFile("./myui.ui")
 ui_file.open(QFile.ReadOnly)
 loader = QUiLoader()
 self.window = loader.load(ui_file)
 ui_file.close()
 self.window.vlayout.addWidget(QLabel("Stuff"))
 self.window.show()
if __name__ == "__main__":
 app = QApplication(sys.argv)
 f = Manager()
 sys.exit(app.exec_())