PyQt5如何使窗口置顶？

Q: 如何使窗口置顶？

QtCore.Qt.WindowStaysOnTopHint

Example：

# -*- coding: utf-8 -*-

import sys

from PyQt5.QtWidgets import QApplication , QMainWindow

from PyQt5 import QtCore, QtGui, QtWidgets

class Ui_MainWindow(object):
    def setupUi(self, MainWindow):
        MainWindow.setObjectName("MainWindow")
        MainWindow.resize(368, 164)
        self.centralwidget = QtWidgets.QWidget(MainWindow)
        self.centralwidget.setObjectName("centralwidget")
        MainWindow.setCentralWidget(self.centralwidget)

        self.retranslateUi(MainWindow)
        QtCore.QMetaObject.connectSlotsByName(MainWindow)

    def retranslateUi(self, MainWindow):
        _translate = QtCore.QCoreApplication.translate
        MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow"))

if __name__ == '__main__':
    '''
    主函数
    '''

    app = QApplication(sys.argv)
    mainWindow = QMainWindow()
    ui = Ui_MainWindow()
    ui.setupUi(mainWindow)
    mainWindow.setWindowFlags(QtCore.Qt.WindowStaysOnTopHint)
    mainWindow.show()
    sys.exit(app.exec_())