python Tkinter学习笔记 简单的计算器 03

'''
Created on 2013-9-27

@author: liangqianwu

'''
#_*_ coding:utf-8_*_
from Tkinter import * 
def frame(root,side):
    w=Frame(root)
    w.pack(side=side,expand=YES,fill=BOTH)
    return w
def button(root,side,text,command=None):
    w=Button(root,text=text,command=command)
    w.pack(side=side,expand=YES,fill=BOTH)
    return w
class Calculator(Frame):
    def __init__(self):
        Frame.__init__(self)
        self.pack(expand=YES,fill=BOTH)
        self.master.title('hello Calculator')
        self.master.iconname('calcl')
        display=StringVar()
        Entry(self,relief=SUNKEN,textvariable=display).pack(side=TOP,expand=YES,fill=BOTH)
        for key in('123','456','789','-0+'):
            keyF=frame(self,TOP)
            for char in key:
                button(keyF,LEFT,char,lambda w=display,s='%s'%char:w.set(w.get()+s))
        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,c=char:w.set(w.get()+''+c+''))
        clearF=frame(self,BOTTOM)
        button(clearF,LEFT,'Clr',lambda w=display:w.set(''))
    def calc(self,display):
        try:
            display.set(`eval(display.get())`)
        except ValueError:
            display.set('ERROR')
if __name__ =='__main__':
    Calculator().mainloop()