[FIXED] Open popup notification on the same monitor where the mainwindow is in python an pyqt5

Issue

In my QMainWindow i have a button which opens a new QDialog in the bottom right monitorcorner with a successmessage when i click it. Now, if i move the QMainWindow to another monitor (i have 3 monitor) and click the button the successmessage popup appears in the monitor where the QMainWindow was opened. What i want is that the popup message appears in the monitor where my QMainWindow actually is. So if i move the QMainWindow to Monitor 1 and click the button, the successpopup should opens in monitor 1. If the QMainWindow is in monitor 2, the successpopup should open in monitor 2 an same for monitor 3.

with

screenNumber = QDesktopWidget().screenNumber(self)

i can read the screennumber where the mainwindow is. and this works fine. Evertime i click the button i read out the screennumber. But i don't found a way, to set the screennumber to my notification. Any ideas?

Edit: maybe it helps if i show my notify class

notes.py

from UIs.UI_notify import Ui_Notification
from PyQt5.QtWidgets import QDialog, QApplication, QDesktopWidget
from PyQt5 import QtCore
from PyQt5.QtCore import QRect, QPropertyAnimation, QTimer
import sys
class icon():
checked = "check-circle"
alert = "times-circle"
question = "question-circle"

class notify(QDialog, Ui_Notification):
    def __init__(self, parent=None):
        super(notify,self).__init__(parent)
        self.setupUi(self)
        self.setWindowFlag(QtCore.Qt.WindowType.FramelessWindowHint)
        self.setAttribute(QtCore.Qt.WidgetAttribute.WA_TranslucentBackground)
        ## Some helping stuff
        ############################################################
        parent_sSize = QDesktopWidget().screenGeometry(parent)
        parent_screenNumber = QDesktopWidget().screenNumber(parent)
        sSize = QDesktopWidget().screenGeometry()
        screenNumber = QDesktopWidget().screenNumber()
        print("notification ScreenNumber = " + str(screenNumber))
        print(sSize.width())
        print(sSize.height())
        print("Parents ScreenNumber = " + str(parent_screenNumber))
        print(parent_sSize.width())
        print(parent_sSize.height())
        self.Note_Exit.clicked.connect(self.close)
        ## ScreenSize from parent
        ############################################################
        self.hidedPos = QRect(parent_sSize.width()-self.width()-10,
                              parent_sSize.height()-self.height()+200,
                              self.frameGeometry().width(),
                              self.frameGeometry().height())
        self.showPos = QRect(parent_sSize.width()-self.width()-10,
                              parent_sSize.height()-self.height()-50,
                              self.frameGeometry().width(),
                              self.frameGeometry().height())
    
    def setNote(self, icon=icon.checked, headline="Headline", text="Text"):
        self.icon = icon
        self.headline = headline
        self.text = text
        self.noty_Label_Icon.setText(self.icon)
        self.noty_Label_Headline.setText(self.headline)
        self.noty_Label_Text.setText(self.text)
        self.setGeometry(self.hidedPos)
        self.anim = QPropertyAnimation(self,b"geometry")
        self.anim.setDuration(700)
        self.anim.setEasingCurve(QtCore.QEasingCurve.OutBack)
        self.anim.setEndValue(self.showPos)
        self.anim.start()
        self.notyTimer = QTimer()
        self.notyTimer.singleShot(4000,self.hideNote)
    def hideNote(self):
        self.anim = QPropertyAnimation(self,b"geometry")
        self.anim.setDuration(700)
        self.anim.setEasingCurve(QtCore.QEasingCurve.InOutBack)
        self.anim.setEndValue(self.hidedPos)
        self.anim.start()
        self.anim.finished.connect(self.close)

if __name__ == "__main__":     
    notes = QApplication(sys.argv)
    dialog = notify()
    dialog.show()
    sys.exit(notes.exec())

Solution

You cannot use the size of the widget during its construction, as at that moment it has a default size (640x480 for top level widgets, 100x30 for widgets created with a parent, including dialogs): the only reliable option is to use the sizeHint() or ensure that the layout has been properly activated with adjustSize().

Then, you don't need the screen to get the target position, as the parent geometry will suffice, but you do need it for the start position, otherwise the dialog will "pop up" at an arbitrary point below the window. Note that QDesktopWidget is considered obsolete, and you should use QScreen instead.

Finally, since you might want to reuse the notification, the start position should be set when the popup is actually being shown, not before. The same goes for the position when hiding (in case the notification could be moved).

class Notify(QDialog, Ui_Notification):
    def __init__(self, parent):
        super().__init__(parent)
        self.setupUi(self)
        self.setWindowFlag(QtCore.Qt.WindowType.FramelessWindowHint)
        self.setAttribute(QtCore.Qt.WA_TranslucentBackground)

        self.showAnim = QPropertyAnimation(self, b'geometry')
        self.showAnim.setDuration(700)
        self.showAnim.setEasingCurve(QtCore.QEasingCurve.OutBack)

        self.hideAnim = QPropertyAnimation(self, b'geometry')
        self.hideAnim.setDuration(700)
        self.hideAnim.setEasingCurve(QtCore.QEasingCurve.InOutBack)

        self.hideTimer = QTimer(self, singleShot=True)
        self.hideTimer.setInterval(4000)

        self.hideTimer.timeout.connect(self.hideNote)
        self.showAnim.finished.connect(self.hideTimer.start)
        self.hideAnim.finished.connect(self.close)

    def setNote(self, icon=icon.checked, headline="Headline", text="Text"):
        self.icon = icon
        self.headline = headline
        self.text = text
        self.noty_Label_Icon.setText(self.icon)
        self.noty_Label_Headline.setText(self.headline)
        self.noty_Label_Text.setText(self.text)

        self.adjustSize() # important!
        endRect = self.rect()
        center = self.parent().geometry().center()
        endRect.moveCenter(center)
        screen = QApplication.screenAt(center)
        startRect = QRect(endRect)
        startRect.moveTop(screen.geometry().bottom())

        self.setGeometry(startRect)
        self.showAnim.setStartValue(startRect)
        self.showAnim.setEndValue(endRect)
        self.showAnim.start()
        self.show()

    def hideNote(self):
        rect = self.geometry()
        self.hideAnim.setStartValue(rect)
        screen = QApplication.screenAt(rect.center())
        rect.moveTop(screen.geometry().bottom())
        self.hideAnim.setEndValue(rect)
        self.hideAnim.start()


if __name__ == "__main__":     
    notes = QApplication(sys.argv)
    notes.setStyle('fusion')
    w = QMainWindow()
    b = QPushButton('click!')
    w.setCentralWidget(b)
    w.show()
    notify = Notify(w)
    b.clicked.connect(lambda: notify.setNote())
    sys.exit(notes.exec())

Be aware that if you're going to create the popup every time, you should also set the WA_DeleteOnClose attribute in order to destroy it when closed, otherwise it will be kept in memory.

^{Note: QTimer.singleShot() is a static function, creating an instance of QTimer to use it is pointless, as that instance won't be used and a new QTimer would be created anyway.}

Answered By - musicamante