PyQt4 center window on active screen

Question

How I can center window on active screen but not on general screen? This code moves window to center on general screen, not active screen:

import sys
from PyQt4 import QtGui

class MainWindow(QtGui.QWidget):

    def __init__(self):
        super(MainWindow, self).__init__()

        self.initUI()

    def initUI(self):

        self.resize(640, 480)
        self.setWindowTitle('Backlight management')
        self.center()

        self.show()

    def center(self):
        frameGm = self.frameGeometry()
        centerPoint = QtGui.QDesktopWidget().availableGeometry().center()
        frameGm.moveCenter(centerPoint)
        self.move(frameGm.topLeft())

def main():
    app = QtGui.QApplication(sys.argv)
    mainWindow = MainWindow()
    sys.exit(app.exec_())

if __name__ == '__main__':
    main()

If I removes self.center() from initUI() then window opened on 0x0 on active screen. I need to open window on active screen and move this window on center of this screen. Thansk!

Answer 1

Modify your center method to be as follows:

def center(self):
    frameGm = self.frameGeometry()
    screen = QtGui.QApplication.desktop().screenNumber(QtGui.QApplication.desktop().cursor().pos())
    centerPoint = QtGui.QApplication.desktop().screenGeometry(screen).center()
    frameGm.moveCenter(centerPoint)
    self.move(frameGm.topLeft())

This function is based on where the mouse point is located. It uses the screenNumber function to determine which screen the mouse is current active on. It then finds the screenGeometry of that monitor and the center point of that screen. Using this method, you should be able to place the window in the center of a screen even if monitor resolutions are different.

Answer 2

One correction for PyQt5 users:

import PyQt5

def center(self):
    frameGm = self.frameGeometry()
    screen = PyQt5.QtWidgets.QApplication.desktop().screenNumber(PyQt5.QtWidgets.QApplication.desktop().cursor().pos())
    centerPoint = PyQt5.QtWidgets.QApplication.desktop().screenGeometry(screen).center()
    frameGm.moveCenter(centerPoint)
    self.move(frameGm.topLeft())