python - Get size of all QStackedWidget items on application launch

Question

I have made an application in PyQt5. I want my application to resize each of the elements of QStackedWidget the moment application is launched.

Currently, it resizes those elements(Pages herein) only when I visit those Pages one by one.

main.py

from PyQt5 import QtCore, QtGui, QtWidgets
import sys

class Main(QtWidgets.QWidget):
    def __init__(self, stacked_widget):
        super(Main, self).__init__()
        self.stacked_widget = stacked_widget

        btn = QtWidgets.QPushButton('Click here!')
        btn.clicked.connect(self.goto)

        layout = QtWidgets.QVBoxLayout()
        layout.addWidget(btn)
        self.setLayout(layout)

    def goto(self):
        self.stacked_widget.setCurrentIndex(1)


class Page(QtWidgets.QWidget):
    def __init__(self, stacked_widget, idx):
        super(Page, self).__init__()
        self.stacked_widget = stacked_widget
        self.idx = idx

        menu = QtWidgets.QToolButton()
        menu.setText('Select Page')
        menu.setStyleSheet("background-color: rgb(191, 191, 191); padding: 1px;")
        viewType = QtWidgets.QMenu()
        group = QtWidgets.QActionGroup(viewType)
        texts = ["Page 01", "Page 02", "Page 03"]
        for text in texts:
            action = QtWidgets.QAction(text, viewType)
            viewType.addAction(action)
            group.addAction(action)
        group.setExclusive(True)
        group.triggered.connect(self.onTriggered)
        menu.setMenu(viewType)
        menu.setPopupMode(QtWidgets.QToolButton.InstantPopup)
        viewType.setStyle(QtWidgets.QStyleFactory.create("Cleanlooks"))
        menu.setFixedWidth(90)

        layout = QtWidgets.QVBoxLayout()
        layout.addWidget(menu)
        self.setLayout(layout)

    def event(self, e):
        if e.type() in (QtCore.QEvent.Show, QtCore.QEvent.Resize):
            print("Page: {}, size".format(self.idx), self.width(), self.height())

        return QtWidgets.QWidget.event(self, e)

    def onTriggered(self, action):
            if action.text() == 'Page 01':
                self.stacked_widget.setCurrentIndex(1)
            elif action.text() == 'Page 02':
                self.stacked_widget.setCurrentIndex(2)
            elif action.text() == 'Page 03':
                self.stacked_widget.setCurrentIndex(3)


class Window(QtWidgets.QMainWindow):
    def __init__(self, parent=None):
        super(Window, self).__init__(parent)

        self.stacked_widget = QtWidgets.QStackedWidget()

        layout = QtWidgets.QVBoxLayout()
        layout.setContentsMargins(0,0,0,0)
        layout.addWidget(self.stacked_widget)

        widget = QtWidgets.QWidget()
        widget.setLayout(layout)
        self.setCentralWidget(widget)

        widget_1 = Main(self.stacked_widget)
        widget_2 = Page(self.stacked_widget, 1)
        widget_3 = Page(self.stacked_widget, 2)
        widget_4 = Page(self.stacked_widget, 3)

        wid_list = [widget_1, widget_2, widget_3, widget_4]

        for wid in wid_list:
            self.stacked_widget.addWidget(wid)

        self.showMaximized()


if __name__ == '__main__':
    app = QtWidgets.QApplication([])
    w = Window()
    sys.exit(app.exec_())

The output should look like below the moment application is launched:

Page: 1, size 1920 986
Page: 1, size 1920 986
Page: 2, size 1920 986
Page: 2, size 1920 986
Page: 3, size 1920 986
Page: 3, size 1920 986

Edit 1:

I need this information at launch time because my actual project consists of video frames on these Pages and I have drawn some points/zones on these frames using OpenCV. In case I'm unable to resize them at launch time, they show a lot of offset at my Dashboard which is defined in Main class (I have just placed a QPushBtton in this example).

Edit 2:

I tried a work-around to this by modifying my Main class as below:

from PyQt5 import QtCore, QtGui, QtWidgets
import sys
from threading import Timer

class Main(QtWidgets.QWidget):
    def __init__(self, stacked_widget):
        .........
        .........
        t = Timer(60.0, self.hello)
        t.start()

    def hello(self):
        for i in range(1,7):
            self.stacked_widget.setCurrentIndex(i)
        self.stacked_widget.setCurrentIndex(0)

But then I get QObject::setParent: Cannot set parent, new parent is in a different thread. Though, the application works in this case but I know it's not the correct approach and I'm afraid it may cause problem in future.

Answer 1

等待大神答复