wxpython Calculator

wxpython Calculator

 
from __future__ import division # So that 8/3 will be 2.6666 and not 2
import wx
from math import * # So we can evaluate "sqrt(8)"

class Calculator(wx.Dialog):
    '''Main calculator dialog'''
    def __init__(self):
        wx.Dialog.__init__(self, None, -1, "Calculator")    
        sizer = wx.BoxSizer(wx.VERTICAL) # Main vertical sizer

        # ____________v
        self.display = wx.ComboBox(self, -1) # Current calculation
        sizer.Add(self.display, 0, wx.EXPAND) # Add to main sizer

        # [7][8][9][/] 
        # [4][5][6][*]
        # [1][2][3][-]
        # [0][.][C][+]
        gsizer = wx.GridSizer(4, 4)
        for row in (("7", "8", "9", "/"),
                    ("4", "5", "6", "*"),
                    ("1", "2", "3", "-"),
                    ("0", ".", "C", "+")):
            for label in row:
                b = wx.Button(self, -1, label)
                gsizer.Add(b)
                self.Bind(wx.EVT_BUTTON, self.OnButton, b)
        sizer.Add(gsizer, 1, wx.EXPAND)

        # [    =     ]
        b = wx.Button(self, -1, "=")
        self.Bind(wx.EVT_BUTTON, self.OnButton, b)
        sizer.Add(b, 0, wx.EXPAND)
        self.equal = b

        # Set sizer and center
        self.SetSizer(sizer)
        sizer.Fit(self)
        self.CenterOnScreen()

    def OnButton(self, evt):
        '''Handle button click event'''
        # Get title of clicked button
        label = evt.GetEventObject().GetLabel() 

        if label == "=": # Calculate
            try:
                compute = self.display.GetValue()
                # Ignore empty calculation
                if not compute.strip():
                    return

                # Calculate result
                result = eval(compute)

                # Add to history
                self.display.Insert(compute, 0)
                
                # Show result
                self.display.SetValue(str(result))
            except Exception, e:
                wx.LogError(str(e))
                return

        elif label == "C": # Clear
            self.display.SetValue("")

        else: # Just add button text to current calculation
            self.display.SetValue(self.display.GetValue() + label)
            self.equal.SetFocus() # Set the [=] button in focus

if __name__ == "__main__":
    # Run the application
    app = wx.App()
    dlg = Calculator()
    dlg.ShowModal()
    dlg.Destroy()