本例制作计算器，运行效果如图100-1所示。执行本例实例后，将创建一个计算器，可以进行常用的加减乘除算术运算。本实例的知识点有：窗口布局器GridLayout的应用，对按钮消息的监听和响应 。-the cases produced calculator, operating results shown in Figure 100-1. Examples of the implementation of the cases, will create a calculator that can be used in arithmetic arithmetic operations. Examples of knowledge of the point : the layout window for GridLayout the application of the information button and listening response.