Maya (PySide2) – Reopen window instead of a new window

Question

I having the problem that every time I press the hotkey(in this case CTRL + A) I open a new window and the old one does not disappear.

I have added a random color and random position into the code so you the new windows. Use the script in Maya:

from PySide2 import QtWidgets, QtCore, QtGui
from PySide2.QtGui import QKeySequence
from PySide2.QtWidgets import QShortcut
from maya import OpenMayaUI
import sys
from random import randrange

try:
    from shiboken import wrapInstance
    import shiboken
except:
    from shiboken2 import wrapInstance
    import shiboken2 as shiboken

class MainWindow(QtWidgets.QMainWindow):
    def __init__(self, parent = None):
        window = OpenMayaUI.MQtUtil.mainWindow()
        mayaWindow = shiboken.wrapInstance(long(window), QtWidgets.QMainWindow)
        super(MainWindow, self).__init__(mayaWindow)

        self.setWindowTitle('Test Window')

        #Set a random color:
        self.setStyleSheet('background-color: rgb(' + str(randrange(255)) + ', ' + str(randrange(255)) + ', ' + str(randrange(255)) + ');')

        self.setWindowFlags(QtCore.Qt.Popup | QtCore.Qt.WindowType.NoDropShadowWindowHint)
        self.resize(630, 400)
        self.releaseKeyboard()
        self.releaseMouse()
        self._window = None

        #Set a random position:
        self.setGeometry(randrange(800), randrange(800), randrange(800), randrange(800))

        # main widget
        mainWidget = QtWidgets.QWidget(self)
        self.setCentralWidget(mainWidget)


    def mousePressEvent(self, QMouseEvent):
        closeOnLostFocus = True

        if closeOnLostFocus:
            xPosition = QMouseEvent.pos().x()
            yPosition = QMouseEvent.pos().y()
            width = self.width()
            height = self.height()
            if xPosition > self.width() or xPosition < 0:
                self.closeWindow()
            if yPosition > self.height() or yPosition < 0:
                self.closeWindow()


    def showWindow(self):
        self.closeWindow()
        if self._window is None:
            self._window = MainWindow()
            self._window.show()


    def closeWindow(self):
        self.close()


def setHotkey(*args):
    hotkey = ''

    window = window = OpenMayaUI.MQtUtil.mainWindow()
    mayaWindow = shiboken.wrapInstance(long(window), QtWidgets.QMainWindow)
    hotkey = 'CTRL + A'
    shortcut = QShortcut(QKeySequence(QtCore.Qt.CTRL + QtCore.Qt.Key_A), mayaWindow)
    shortcut.setContext(QtCore.Qt.ApplicationShortcut)
    shortcut.activated.connect(startApp)
    return hotkey


def startApp(*args):
    app = QtWidgets.QApplication.instance()
    if app is None:
        app = QtWidgets.QApplication(sys.argv)
    mainWindow = MainWindow()
    mainWindow.showWindow()

setHotkey()

I would like that a new window appears and the one created before that disappears, so that only one exists at a time.

Answer 1

You have to have a single variable that stores the only object, that's why I have created a global variable:

mainWindow = None

def startApp(*args):
    app = QtWidgets.QApplication.instance()
    if app is None:
        app = QtWidgets.QApplication(sys.argv)
    global mainWindow
    mainWindow = MainWindow()
    mainWindow.show()

setHotkey()