pyqt5 not showing window [duplicate]

问题:

This question already has answers here:

PyQt: app.exec_() stops all following code from running (4 answers)

Should I use `app.exec()` or `app.exec_()` in my PyQt application? (2 answers)

Closed 2 years ago.

I really hope someone can help me out on this one. Im trying to get started with using pyqt5, and have pretty much copied this code from a course that i am taking. the code seems to execute without any problems, but the window that i should be seeing is simply not appearing, what am I doing wrong? Im working on ubuntu 18 by the way

from PyQt5.QtCore import *
from PyQt5.QtWidgets import *


class Page(QWidget):
    def __init__(self, parent=None):
    super(Page, self).__init__(parent)

    my_label = QLabel("This is my labet")
    layout = QVBoxLayout()

    layout.addWidget(my_label)

    mainLayout = QGridLayout()
    mainLayout.addLayout(layout, 0, 1)

    self.setLayout(mainLayout)
    self.setWindowTitle("my first Qt app")

if __name__ == "__mongo__":
    import sys
    print("LOEREE")
    app = QApplication(sys.argv)

window = Page()
window.show()

回答1:

In your example there were some typos and at the end there was no line sys.exit (app.exec _ ()) which starts the main loop of the application. From here begins the processing of events.

from PyQt5.QtCore    import * 
from PyQt5.QtWidgets import *

class Page(QWidget): 
    def __init__(self, parent=None):             # __init__
        super(Page, self).__init__(parent)       # __init__

        my_label = QLabel("This is my labet")
        layout   = QVBoxLayout()

        layout.addWidget(my_label)

        mainLayout = QGridLayout()
        mainLayout.addLayout(layout, 0, 1)

        self.setLayout(mainLayout)
        self.setWindowTitle("my first Qt app")

if __name__ == '__main__':                       # 
    import sys 
    print("LOEREE") 
    app = QApplication(sys.argv)
    window = Page()
    window.show()
    sys.exit(app.exec_())                         # !!!