### Making a calculator in Python using pyface and raw Qt.

I wrote yesterday about making a calculator GUI using enthought's traitsUI package. Well, for fun, I rewrote the whole damn thing using Enthought's pyface package in raw Qt. The main difference is that we have lost the ability to automatically monitor the changes in the attributes i.e monitor when the buttons are being pressed. So, we have to now manually connect the QPushButton objects to functions that handle what to do when one of the buttons is pressed. And the layout of the buttons is a little harder to define as well. Well, harder for me because I still haven't been able to wrap my head around Qt.

Anyway, that's all for today I guess. Ohh, also, the 0 button isn't behaving well and I don't think the . button is either! I wanted to write unittests to automate checking whether or not the app/program is working as its supposed to. I'm still trying to learn how to write unittests, for GUI elements, after a failed attempt a couple of days back.

Again, the code was highlighted using this awesome website! And any comments/suggestions are welcome and highly appreciated! :)

#  Copyright (c) 2007, Enthought, Inc.

# http://zetcode.com/gui/qt4/layoutmanagement/

"""
Implementation of a TableEditor demo plugin for Traits UI demo program

This demo shows the full behavior of a straightforward TableEditor.  Only
one style of TableEditor is implemented, so that is the one shown.
"""

# Import statements:

import sys

from traits.api import Int, Float
from pyface.qt.QtGui import *
from pyface.qt.QtCore import QCoreApplication
#from pyface.qt import QString

# The class to be edited with the TableEditor:
class Application ():
compute_box = 0.0
temp = 0.0
count = 0
dot = -1

app = QApplication(sys.argv)
window = QWidget()
textEdit = QTextEdit()
textEdit.setText(unicode(compute_box))

nine_button = QPushButton('9')
eight_button = QPushButton('8')
seven_button = QPushButton('7')
six_button = QPushButton('6')
five_button = QPushButton('5')
four_button = QPushButton('4')
three_button = QPushButton('3')
two_button = QPushButton('2')
one_button = QPushButton('1')

equals_button = QPushButton('=')
subtract_button = QPushButton('-')
mul_button = QPushButton('*')
div_button = QPushButton('/')
zero_button = QPushButton('0')
dot_button = QPushButton('.')

clr_button = QPushButton('clr')

def nine_button_fired(self):
if self.dot == -1:
self.compute_box = self.compute_box*10 +9.0
self.textEdit.setText(unicode(self.compute_box))
else:
self.compute_box = (self.compute_box*10**(self.dot) +9.0)/10**(self.dot)
self.dot +=1
self.textEdit.setText(unicode(self.compute_box))

def eight_button_fired(self):
if self.dot == -1:
self.compute_box = self.compute_box*10 +8.0
self.textEdit.setText(unicode(self.compute_box))
else:
self.compute_box = (self.compute_box*10**(self.dot) +8.0)/10**(self.dot)
self.dot +=1
self.textEdit.setText(unicode(self.compute_box))

def seven_button_fired(self):
if self.dot == -1:
self.compute_box = self.compute_box*10 +7.0
self.textEdit.setText(unicode(self.compute_box))
else:
self.compute_box = (self.compute_box*10**(self.dot) +7.0)/10**(self.dot)
self.dot +=1
self.textEdit.setText(unicode(self.compute_box))

def six_button_fired(self):
if self.dot == -1:
self.compute_box = self.compute_box*10 +6.0
self.textEdit.setText(unicode(self.compute_box))
else:
self.compute_box = (self.compute_box*10**(self.dot) +6.0)/10**(self.dot)
self.dot +=1
self.textEdit.setText(unicode(self.compute_box))

def five_button_fired(self):
if self.dot == -1:
self.compute_box = self.compute_box*10 +5.0
self.textEdit.setText(unicode(self.compute_box))
else:
self.compute_box = (self.compute_box*10**(self.dot) +5.0)/10**(self.dot)
self.dot +=1
self.textEdit.setText(unicode(self.compute_box))

def four_button_fired(self):
if self.dot == -1:
self.compute_box = self.compute_box*10 +4.0
self.textEdit.setText(unicode(self.compute_box))
else:
self.compute_box = (self.compute_box*10**(self.dot) +4.0)/10**(self.dot)
self.dot +=1
self.textEdit.setText(unicode(self.compute_box))

def three_button_fired(self):
if self.dot == -1:
self.compute_box = self.compute_box*10 +3.0
self.textEdit.setText(unicode(self.compute_box))
else:
self.compute_box = (self.compute_box*10**(self.dot) +3.0)/10**(self.dot)
self.dot +=1
self.textEdit.setText(unicode(self.compute_box))

def two_button_fired(self):
if self.dot == -1:
self.compute_box = self.compute_box*10 +2.0
self.textEdit.setText(unicode(self.compute_box))
else:
self.compute_box = (self.compute_box*10**(self.dot) +2.0)/10**(self.dot)
self.dot +=1
self.textEdit.setText(unicode(self.compute_box))

def one_button_fired(self):
if self.dot == -1:
self.compute_box = self.compute_box*10 +1.0
self.textEdit.setText(unicode(self.compute_box))
else:
self.compute_box = (self.compute_box*10**(self.dot) +1.0)/10**(self.dot)
self.dot +=1
self.textEdit.setText(unicode(self.compute_box))

def zero_button_fired(self):
# does some weird shit!
if self.dot == -1:
self.compute_box = self.compute_box*10
self.textEdit.setText(unicode(self.compute_box))
#        else:
# dunno what to do when we want to add
# after zero!

def dot_button_fired(self):
self.dot = 1

def eval_expr(self):
if self.count == 1:
self.compute_box += self.temp
elif self.count == -1:
self.compute_box = self.temp -self.compute_box
elif self.count == 2:
self.compute_box = self.compute_box*self.temp
elif self.count == -2:
self.compute_box = self.temp/self.compute_box
self.dot = -1
self.count = 0
self.textEdit.setText(unicode(self.compute_box))
self.temp = 0.0

self.temp = self.compute_box
self.compute_box = 0.0
self.count = 1
self.dot = -1
self.textEdit.setText(unicode(self.compute_box))

def subtract_button_fired(self):
self.temp = self.compute_box
self.compute_box = 0.0
self.count = -1
self.dot = -1
self.textEdit.setText(unicode(self.compute_box))

def mul_button_fired(self):
self.temp = self.compute_box
self.compute_box = 0.0
self.count = 2
self.dot = -1
self.textEdit.setText(unicode(self.compute_box))

def div_button_fired(self):
self.temp = self.compute_box
self.compute_box = 0.0
self.count = -2
self.dot = -1
self.textEdit.setText(unicode(self.compute_box))

def clr_button_fired(self):
self.temp = 0.0
self.compute_box = 0.0
self.count = 0
self.dot =-1
self.textEdit.setText(unicode(self.compute_box))

def main(self):
self.nine_button.clicked.connect(self.nine_button_fired)
self.eight_button.clicked.connect(self.eight_button_fired)
self.seven_button.clicked.connect(self.seven_button_fired)
self.six_button.clicked.connect(self.six_button_fired)
self.five_button.clicked.connect(self.five_button_fired)
self.four_button.clicked.connect(self.four_button_fired)
self.three_button.clicked.connect(self.three_button_fired)
self.two_button.clicked.connect(self.two_button_fired)
self.one_button.clicked.connect(self.one_button_fired)
self.zero_button.clicked.connect(self.zero_button_fired)

self.mul_button.clicked.connect(self.mul_button_fired)
self.subtract_button.clicked.connect(self.subtract_button_fired)
self.div_button.clicked.connect(self.div_button_fired)
self.dot_button.clicked.connect(self.dot_button_fired)
self.clr_button.clicked.connect(self.clr_button_fired)
self.equals_button.clicked.connect(self.eval_expr)

textlayout = QGridLayout()
layout = QGridLayout()
mainlayout = QVBoxLayout()

self.window.setLayout(mainlayout)
self.window.setWindowTitle("Calculator : Poruri Sai Rahul")

self.window.show()

return self.app.exec_()

# Create the demo:
demo = Application()

# Run the demo (if invoked from the command line):
if __name__ == '__main__':
demo.main()


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