如何正确运行pyqt5应用程序？

Question

I can't get the GUI for my application to run in the manner that I need it to. My question is, given the below criteria, how do I go about setting up and running the GUI properly. The lack of good documentation that I have found is insanely frustrating (maybe I'm looking in the wrong places?).

I have a main window in a file called MainCustomerWindow.py containing a class by the same name. This is where all the code from the qt designer is. I have another class file called GUIController. The GUIController class does just that, controls the multiple GUI windows. It is in this GUIController class that I am trying to instantiate and run the MainCustomerWindow. Here is the code I have been trying.

def setup_window(self):
    APP = QtWidgets.QApplication(sys.argv)
    Window = MainCustomerWindow()
    Window.setupUi(QtWidgets.QMainWindow)
    Window.show()
    sys.exit(APP.exec_())

Just as a side note, I come from JavaFX and Swing, and don't fully understand the workflow for pyqt5. So if someone could add an explanation for that as well it would be greatly appreciated.

Answer 1

The class generated by Qt Designer is not a widget, it is a class used to fill an existing widget, so you must create an object in the window, assuming you have used the "Main Window" template, then the widget must be QMainWindow (if it is another maybe you should use QDialog or QWidget ), then you have to create another class that belongs to the design, and using the method setupUi() you must pass the widget to fill it:

def setup_window(self):
    app = QtWidgets.QApplication(sys.argv)
    # create window
    window = QtWidgets.QMainWindow()

    ui = MainCustomerWindow()
    # fill window
    ui.setupUi(window)

    window.show()

    sys.exit(app.exec_())

Although a better option is to create a new class and have it inherit from both:

class MainWindow(QtWidgets.QMainWindow, MainCustomerWindow):
    def __init__(self, parent=None):
        super(MainWindow, self).__init__(parent)
        self.setupUi(self)

If you want to get detailed information I recommend you read the following:

• http://pyqt.sourceforge.net/Docs/PyQt5/designer.html

Answer 2

You can try taking the code you have there and adding it to the main statement at the end of your app's script. You can also have this statement instantiate your class where the init method contains the setupui() call. For example:

if __name__ == '__main__':
    app = QWidgets.QApplication(sys.argv)
    window = QMainWindow()
    main_window = MainCustomerWindow()

    window.show()
    sys.exit(app.exec())

This code first sets up the PyQt app as an instance of QApplication. Next it instantiates an instance of QMainWindow so that PyQt knows what to display as the main app starts. In my experience, I've put setupui() in the init method of the app class. In your case, in the init method of MainCustomerWindow Finally, window.show() tells PyQt to begin rendering the main window.