Calc_test.py

import wx
from math import *

class CalcFrame(wx.Frame):
	
	def __init__(self, title):
		super(CalcFrame,self).__init__(None, title=title, size=(300,250))
		self.InitUI()
		self.Centre()
		self.Show()

	def InitUI(self):
		vbox = wx.BoxSizer(wx.VERTICAL)
		self.textprint = wx.TextCtrl(self,-1,'', style=wx.TE_RIGHT|wx.TE_READONLY)
		self.equation=""
		vbox.Add(self.textprint, flag=wx.EXPAND|wx.TOP|wx.BOTTOM, border=4)

		gridBox = wx.GridSizer(5,4,5,5)
		labels = ['AC', 'DEL', 'pi', 'CLOSE', '7', '8', '9', '/', '4', '5', '6', '*', '1', '2', '3', '-', '0', '.', '=', '+']

		for label in labels:
			buttonItem = wx.Button(self, label=label)
			self.createHandler(buttonItem, label)
			gridBox.Add(buttonItem, 1, wx.EXPAND)
		
		vbox.Add(gridBox, proportion=1, flag=wx.EXPAND)
		self.SetSizer(vbox)

	def createHandler(self, button, labels):
		item = "DEL AC = CLOSE"
				
		if labels not in item:
			self.Bind(wx.EVT_BUTTON, self.OnAppend, button)
		elif labels == 'DEL':
			self.Bind(wx.EVT_BUTTON, self.OnDel, button)
		elif labels == 'AC':
			self.Bind(wx.EVT_BUTTON, self.OnAc, button)
		elif labels == '=':
			self.Bind(wx.EVT_BUTTON, self.OnTarget, button)
		elif labels == 'CLOSE':
                        self.Bind(wx.EVT_BUTTON, self.OnExit, button)


	def OnAppend(self,event):
		eventbutton = event.GetEventObject()
		label = eventbutton.GetLabel()
		self.equation += label
		self.textprint.SetValue(self.equation)

	def OnDel(self,event):
		self.equation = self.equation[:-1]
		self.textprint.SetValue(self.equation)

	def OnAc(self,event):
		self.textprint.Clear()	
		self.equation=""

	def OnTarget(self, event):
		string = self.equation

		try:
			target = eval(string)
			self.equation = str(target)
			self.textprint.SetValue(self.equation)
		except SyntaxError:
			dlg = wx.MessageDialog(self, u'Worrg format!', u'pls attention', wx.OK|wx.ICON_INFORMATION)
			dlg.ShowModal()
			dlg.Destory()

	def OnExit(self, event):
		self.close()



if  __name__ == '__main__':
	app = wx.App()
	CalcFrame(title='Calculator')
	app.MainLoop()