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,text="5",command=lambda: callback(5) ).grid(row=1,text="6",command=lambda: callback(6) ).grid(row=1,text="7",command=lambda: callback(7) ).grid(row=2,text="8",command=lambda: callback(8) ).grid(row=2,text="9",command=lambda: callback(9) ).grid(row=2,text="0",command=lambda: callback(0) ).grid(row=3,text="+",command=lambda: callback1("+") ).grid(row=3,text="-",command=lambda: callback1("-") ).grid(row=3,text="*",command=lambda: callback1("*") ).grid(row=4,text="/",command=lambda: callback1("/") ).grid(row=4,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,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,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,char) 
    btn.bind('<ButtonRelease - 1>',lambda e,s = self,w = display:s.calc(w),'+') 
 
   else: 
    btn = button(opsF,s = '%s' %char:w.set(w.get() + s)) 
  #添加清除按钮 
  clearF = frame(self,BOTTOM) 
  button(clearF,'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()