from tkinter import *
from tkinter import messagebox
import random
class Application(Frame):
    def __init__(self, master=None):
        super().__init__(master)  # super()代表的是父类的定义,而不是父类对象
        self.master = master
        self.pack()
        self.createWidget()
    def createWidget(self):
        """通过grid布局管理实现计算器的界面"""
        btnText=(('MC','M+','M-','MR'),
                 ('C','±','÷','×'),
                 (7,8,9,'-'),
                 (4,5,6,'+'),
                 (1,2,3,'='),
                 (0,'.'))
        Entry(self).grid(row=0,column=0,columnspan=4,pady=10)
        for rindex,r in enumerate(btnText):
            for cindex,c in enumerate(r):
                if c == '=':
                    Button(self,text=c,width=2).grid(row=rindex+1,column=cindex,rowspan=2,sticky=NSEW)
                elif c == 0:
                    Button(self, text=c, width=2).grid(row=rindex+1 , column=cindex, columnspan=2, sticky=NSEW)
                elif c == '.':
                    Button(self, text=c, width=2).grid(row=rindex + 1, column=cindex+1, rowspan=2, sticky=NSEW)
                else:
                    Button(self, text=c, width=2).grid(row=rindex + 1, column=cindex, sticky=NSEW)
if __name__ == '__main__':
    root = Tk()
    root.geometry("400x300+200+300")
    root.title("一个经典的GUI程序类测试")
    app = Application(master=root)
    root.mainloop()老师,为什么我的等于号没有跨行的
