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