学习布局设计和把组件添加到容器时控制组件在容器中的位置。编写一个应用程序实现日历的查阅，点击上月和下月两个按钮，查阅不同月份的日历。-Learning the layout design and components are added to the location of control components to the container in the container. Write an application to access the calendar, click on the