PyQt5显示一个空白的窗口

效果如下图：
 1 """
 2 In this example, we create a simple
 3 window in PyQt5.
 4 """
 5 
 6 # provide the necessary imports.
 7 # The basic widgets are located in PyQt5.QtWidgets module
 8 import sys
 9 from PyQt5.QtWidgets import QApplication, QWidget
10 
11 if __name__ == '__main__':
12 
13     app = QApplication(sys.argv)  # create an application object
14     w = QWidget()  # The QWidget widget is the base class of all user interface objects
15     w.resize(250, 150)  # The resize() method resizes the widget
16     w.move(300, 300)  # The move() method moves the widget to a position on the screen
17     w.setWindowTitle('Simple')  # set the title of the window with setWindowTitle()
18     w.show()  # The show() method displays the widget on the screen
19     sys.exit(app.exec_())  # The sys.exit() method ensures a clean exit