定义如下界面，分别在两个文本框中输入一个小数，当点击 run按钮时把这两个数的和在第三个文本框中显示出来，当点击restart时把三个文本框的内容都清空开始新一轮的运算。-Defined as the interface, respectively, in two text box, enter a decimal number, click the run button when these two numbers in the third text box is displayed when clicking restart when the contents of the three text boxes are cleared start a new round of air operations.