[Tutor] My best GUI app so far.

[Kent Johnson]

Jacob S. wrote:
>> For some
> 
>>reason I don't understand, for me add works from the keyboard and multiply
> 
> doesn't!?
> 
> The same thing happened to me. That's when I realized that we were using 'x'
> for the text on the multiply button and binding 'x' to multiply(), whereas
> both of us were trying to use '*' to initiate multiply().

Doh. Of course!

BTW I tried the program with
   command=lambda : self.adddigit('0')
etc (i.e. no *x) and it works fine. The extra (event) argument is consumed by the lambda in 
makeButton(). Probably it was needed in some intermediate version.

> 
> If I don't like the * in the text of the button, I'll have to set up a
> seperate binding. Here's the code again, a few things changed. -Added
> binding of spacebar to clear function
>                -Added binding of enter key to equal - for use with the
> number off to the right of the keyboard.
>                -Changed text on button so 'x' now reads '*'

I would make these bindings in createWidgets(), that is closer to where the other bindings are made 
- it's helpful to keep like code together.

Even better - make the extra bindings an option argument to makeButton(), like this:
   self.makeButton(text='ON/C',command=self.clear,row=1,column=4, extraBindings=['<space>', 'C'])

and
      def makeButton(self, text, command, row, column, extraBindings=[]):
          button = Button(self,text=text,command=command,width=4,height=3)
          button.grid(row=row,column=column)
          if len(text) == 1:
              self.bind_all(text,lambda x: command())
          for binding in extraBindings:
              self.bind_all(binding,lambda x: command())

Kent

> 
> As always, Feel free to give suggestions.
> 
> Thanks for helping out so much!

You're welcome!

> Jacob Schmidt
> 
> ###Start of Calculator.py###
> from __future__ import division
> from Tkinter import *
> 
> class Application(Frame):
>      def ctb(self):
>          if self.shouldblank:
>              self.distext.set('')
>              self.shouldblank = False
> 
>      def adddigit(self, digit):
>          self.ctb()
>          self.distext.set(self.distext.get()+digit)
> 
>      def adddigitdot(self):
>          if not self.distext.get().count('.'):
>              self.ctb()
>              self.distext.set(self.distext.get()+'.')
> 
>      def equal(self):
>          if self.action:
>              self.newnum = self.distext.get()
>              self.newnum = str(eval(self.oldnum+self.action+self.newnum))
>              self.distext.set(self.newnum)
>              self.oldnum = '0'
>              self.action = ''
>              self.shouldblank = True
> 
>      def add(self):
>          self.handleOperator('+')
> 
>      def subtract(self):
>          self.handleOperator('-')
> 
>      def multiply(self):
>          self.handleOperator('*')
> 
>      def divide(self):
>          self.handleOperator('/')
> 
> 
>      def handleOperator(self, oper):
>          if self.action:
>              self.equal()
>              self.oldnum = self.distext.get()
>              self.action = oper
>          else:
>              self.oldnum = self.distext.get()
>              self.action = oper
>          self.shouldblank = True
> 
> 
>      def clear(self):
>          self.action = ''
>          self.oldnum = '0'
>          self.distext.set('0')
>          self.shouldblank = True
> 
>      def memrecall(self):
>          self.distext.set(self.memory)
>          self.shouldblank = True
> 
>      def memminus(self):
>          self.memory = str(eval(self.memory+"-"+self.distext.get()))
>          self.shouldblank = True
> 
>      def memplus(self):
>          self.memory = str(eval(self.memory+"+"+self.distext.get()))
>          self.shouldblank = True
> 
> 
>      def makeButton(self, text, command, row, column):
>          button = Button(self,text=text,command=command,width=4,height=3)
>          button.grid(row=row,column=column)
>          if len(text) == 1:
>              self.bind_all(text,lambda x: command())
> 
> 
>      def createWidgets(self):
>          self.distext = StringVar()
>          self.display
> =Entry(self,textvariable=self.distext,width=22,justify='right')
>          self.display.grid(row=0,column=1,columnspan=4)
> 
>          self.makeButton(text='0',command=lambda *x:
> self.adddigit('0'),row=5,column=1)
>          self.makeButton(text='1',command=lambda *x:
> self.adddigit('1'),row=4,column=1)
>          self.makeButton(text='2',command=lambda *x:
> self.adddigit('2'),row=4,column=2)
>          self.makeButton(text='3',command=lambda *x:
> self.adddigit('3'),row=4,column=3)
>          self.makeButton(text='4',command=lambda *x:
> self.adddigit('4'),row=3,column=1)
>          self.makeButton(text='5',command=lambda *x:
> self.adddigit('5'),row=3,column=2)
>          self.makeButton(text='6',command=lambda *x:
> self.adddigit('6'),row=3,column=3)
>          self.makeButton(text='7',command=lambda *x:
> self.adddigit('7'),row=2,column=1)
>          self.makeButton(text='8',command=lambda *x:
> self.adddigit('8'),row=2,column=2)
>          self.makeButton(text='9',command=lambda *x:
> self.adddigit('9'),row=2,column=3)
>          self.makeButton(text='.',command=self.adddigitdot,row=5,column=2)
>          self.makeButton(text="=",command=self.equal,row=5,column=3)
>          self.makeButton(text='+',command=self.add,row=5,column=4)
>          self.makeButton(text="-",command=self.subtract,row=4,column=4)
>          self.makeButton(text='*',command=self.multiply,row=3,column=4)
>          self.makeButton(text='/',command=self.divide,row=2,column=4)
>          self.makeButton(text='ON/C',command=self.clear,row=1,column=4)
>          self.makeButton(text='MRC',command=self.memrecall,row=1,column=1)
>          self.makeButton(text="M-",command=self.memminus,row=1,column=2)
>          self.makeButton(text="M+",command=self.memplus,row=1,column=3)
> 
> 
>      def __init__(self, master=None):
>          Frame.__init__(self,master)
>          self.master.title("Calculator by Jacob, Inc.")
>          self.pack(expand=True)
>          self.bind_all('<space>',lambda x: self.clear())
>          self.bind_all('<Return>',lambda x: self.equal())
>          self.oldnum = '0'
>          self.memory = '0'
>          self.action = ''
>          self.shouldblank = True
>          self.createWidgets()
> 
> app = Application()
> app.mainloop()
> ###End of Calculator.py###
> 
>