Good afternoon. This is an MRE of the problem that you can easily run in your machine
import sys
from PyQt5.QtWidgets import (
QWidget, QMenuBar, QMenu, QApplication,
QAction, QMainWindow,
QVBoxLayout, QLabel
)
class mainwindow(QMainWindow):
def __init__(self, screen2, screen3):
super().__init__()
self._screen2 = screen2
self._screen3 = screen3
self.tela()
self.acoes()
self.sinais()
def tela(self):
layout = QVBoxLayout()
label = QLabel('screen 1')
layout.addWidget(label)
widget_central = QWidget()
self.setCentralWidget(widget_central)
widget_central.setLayout(layout)
def acoes(self):
self.action_screen2 = QAction('screen 2')
self.action_screen3 = QAction('screen 3')
menu_opt = QMenuBar(self)
self.setMenuBar(menu_opt)
menu = QMenu("avaliable screens", self)
menu_opt.addMenu(menu)
screen_menu = menu.addMenu("screens")
screen_menu.addAction(self.action_screen2)
screen_menu.addAction(self.action_screen3)
def sinais(self):
self.action_screen2.triggered.connect(self.tela2)
self.action_screen3.triggered.connect(self.tela3)
def tela2(self):
self.setCentralWidget(self._screen2)
def tela3(self):
self.setCentralWidget(self._screen3)
class widget1(QWidget):
def __init__(self):
super().__init__()
self.screen()
def screen(self):
layout = QVBoxLayout()
label = QLabel('screen 2')
layout.addWidget(label)
self.setLayout(layout)
class widget2(QWidget):
def __init__(self):
super().__init__()
self.screen()
def screen(self):
layout = QVBoxLayout()
label = QLabel('screen 3')
layout.addWidget(label)
self.setLayout(layout)
def main():
applic = QApplication(sys.argv)
screen2 = widget1()
screen3 = widget2()
app = mainwindow(screen2, screen3)
app.show()
sys.exit(applic.exec_())
if __name__ == '__main__':
main()
If you run this code you'll be presented with a menu which allows you to choose from different screen options, in this sample the screens are made of a label that reads the number of the chosen screen, I'm using QActions to make the connections. Screen 1 is default, screens 2 and 3 are represented by 2 classes that inherit from QWidget and what "glue" things together is the setCentralWidget() function of the QMainWindow class.
This works for the first few changes, like: from screen1 (default) to screen2 to 3. But this only work once. Let's say that you selected screen 2 then 3, then if you want to go back to screen 2 (and vice-versa) the application will eventually crash.
What can I do to prevent the application to close itself if I want to go back to an already selected screen?
