Using a custom PySide2 widget in Qt Designer

Question

I\'m searching for a way to use custom widgets in Qt Designer written with Qt for Python (PySide2) effectively.

I found out, that it is possible to design the GUI wi

Answer 1

There are 2 main ways to use a custom widget in Qt Designer:

1. Promoting the widget:

This is the simplest and least laborious way, if it's an internal widget you just have to right click on the widget and select Promote To ..., then in:

• Base Class Name choose the class from which you inherit
• Promoted Class Name place the name of the class a
• Header File place the path of the file changing the extension .py to .h

What the above does is generate the following:

...
    
...
 
  
   RadialBar
   QWidget
   
radialbar.h
   1
  
 
...

That is, change class, and add a field in customwidget pointing to the name of the class: NAME_OF_CLASS , name of the class they inherit CLASS_EXTENDS and file path changing the file extension from .py to .h

PATH_OF_FILE.h

, that is, the same data as You entered the form.

In the case of the root widget it can not be done through Qt Designer, but I see that you have understood the logic but you have not modified everything correctly, your main mistake is to point out the class from which they inherit

 
  
   MyMainWindow
   QMainWindow <----
   
mymainwindow.h
   1
  
 

So the correct file is:

custom_widget_modified.ui

 MainWindow
 
  
   
    0
    0
    800
    600
   
  
  
   MainWindow
  
  
   
    
     0
     0
     155
     15
    
   
   
    
     
      
       TextLabel
      
     
    
    
     
      
       TextLabel
      
     
    
    
     
      
       TextLabel
      
     
    
   
  
  
   
    
     0
     0
     800
     21
    
   
   
    
     File
    
    
   
   
  
  
   
    
     0
     0
     3
     18
    
   
  
  
   
    Exit
   
  
 
 
  
   MyMainWindow
   QMainWindow
   
mymainwindow.h
   1
  
 
 
 
  
   actionExit
   triggered()
   MainWindow
   close()
   
    
     -1
     -1
    
    
     399
     299
    
   
  
 

mymainwindow.py

import sys

from PySide2.QtUiTools import QUiLoader
from PySide2.QtWidgets import QApplication, QMainWindow, QMessageBox
from PySide2.QtCore import QFile


class MyMainWindow(QMainWindow):
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.setWindowTitle("Demo QtWidget App")

    def closeEvent(self, event):
        msgBox = QMessageBox()
        msgBox.setWindowTitle("Quit?")
        msgBox.setText("Exit application?")
        msgBox.setStandardButtons(QMessageBox.Yes | QMessageBox.No)
        msgBox.setDefaultButton(QMessageBox.No)
        ret = msgBox.exec_()
        if ret == QMessageBox.Yes:
            event.accept()
        else:
            event.ignore()


if __name__ == '__main__':
    app = QApplication([])
    file = QFile("custom_widget_modified.ui")
    file.open(QFile.ReadOnly)
    loader = QUiLoader()
    loader.registerCustomWidget(MyMainWindow)
    main_window = loader.load(file)
    main_window.show()
    sys.exit(app.exec_())

2. Promoting the widget: