PyQt5显示一个空白的窗口

效果如下图：

 """
 In this example, we create a simple
 window in PyQt5.
 """

 # provide the necessary imports.
 # The basic widgets are located in PyQt5.QtWidgets module
 import sys
 from PyQt5.QtWidgets import QApplication, QWidget

 if __name__ == '__main__':

     app = QApplication(sys.argv)  # create an application object
     w = QWidget()  # The QWidget widget is the base class of all user interface objects
     w.resize(250, 150)  # The resize() method resizes the widget
     w.move(300, 300)  # The move() method moves the widget to a position on the screen
     w.setWindowTitle('Simple')  # set the title of the window with setWindowTitle()
     w.show()  # The show() method displays the widget on the screen
     sys.exit(app.exec_())  # The sys.exit() method ensures a clean exit