PyQt4 center window on active screen

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())

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.