基于python的Tkinter实现一个简易计算器

#coding:utf-8
from Tkinter import *
import time
root = Tk()
def cacl(input_str):
if "x" in input_str:
ret = input_str.split("x")
return int(ret[0]) * int(ret[1])
def callback(n):
print n
def callback1(n):
print n
class App:
def __init__(self, master):
frame1 = Frame(master)
frame1.pack()
frame = Frame(master)
frame.pack()
Button(frame, text="1",command=lambda: callback(1) ).grid(row=0,column=0)
Button(frame, text="2",command=lambda: callback(2) ).grid(row=0,column=1)
Button(frame, text="3",command=lambda: callback(3) ).grid(row=0,column=2)
Button(frame, text="4",command=lambda: callback(4) ).grid(row=1,column=0)
Button(frame, text="5",command=lambda: callback(5) ).grid(row=1,column=1)
Button(frame, text="6",command=lambda: callback(6) ).grid(row=1,column=2)
Button(frame, text="7",command=lambda: callback(7) ).grid(row=2,column=0)
Button(frame, text="8",command=lambda: callback(8) ).grid(row=2,column=1)
Button(frame, text="9",command=lambda: callback(9) ).grid(row=2,column=2)
Button(frame, text="0",command=lambda: callback(0) ).grid(row=3,column=0)
Button(frame, text="+",command=lambda: callback1("+") ).grid(row=3,column=1)
Button(frame, text="-",command=lambda: callback1("-") ).grid(row=3,column=2)
Button(frame, text="*",command=lambda: callback1("*") ).grid(row=4,column=1)
Button(frame, text="/",command=lambda: callback1("/") ).grid(row=4,column=2)
Button(frame, text="=", command=self.say_hi).grid(row=4,column=0)
w = Label(frame1,text="输入结果")
w.pack()
self.e = Entry(frame1)
self.e.pack(padx=5)
w1 = Label(frame1,text="计算结果")
w1.pack()
v = StringVar()
e1 = Entry(frame1, textvariable=v)
v.set("")
self.v = v
e1.pack()
def say_hi(self):
print "hi there, everyone!",self.e.get()
input_str = self.e.get()
self.v.set(cacl(input_str))
app = App(root)
root.mainloop()

from Tkinter import * 
 
#创建横条型框架 
def frame(root, side): 
 w = Frame(root) 
 w.pack(side = side, expand = YES, fill = BOTH) 
 return w 
#创建按钮 
def button(root, side, text, command = None): 
 w = Button(root, text = text, command = command) 
 w.pack(side = side, expand = YES, fill = BOTH) 
 return w 
#继承了Frame类，初始化程序界面的布局 
class Calculator(Frame): 
 def __init__(self): 
 
 Frame.__init__(self) 
 
 self.pack(expand = YES, fill = BOTH) 
 self.master.title('Simple Calculater') 
 
 display = StringVar() 
 #添加输入框 
 Entry(self, relief = SUNKEN, 
 textvariable = display).pack(side = TOP, expand = YES, 
   fill = BOTH) 
 #添加横条型框架以及里面的按钮 
 for key in('123', '456', '789', '-0.'): 
 keyF = frame(self, TOP) 
 for char in key: 
 button(keyF, LEFT, char, lambda w = display, c = char:w.set(w.get() + c)) 
 #添加操作符按钮 
 opsF = frame(self, TOP) 
 for char in '+-*/=': 
 if char == '=': 
 btn = button(opsF, LEFT, char) 
 btn.bind('<ButtonRelease - 1>', lambda e, s = self, w = display:s.calc(w), '+') 
 
 else: 
 btn = button(opsF, LEFT, char, lambda w = display, s = '%s' %char:w.set(w.get() + s)) 
 #添加清除按钮 
 clearF = frame(self, BOTTOM) 
 button(clearF, LEFT, 'clear', lambda w = display:w.set('')) 
 
 #调用eval函数计算表达式的值 
 def calc(self, display): 
 try: 
 display.set(eval(display.get())) 
 except: 
 display.set("ERROR") 
#程序的入口 
if __name__ == '__main__': 
 print('ok') 
 Calculator().mainloop()