Parse command-line and show a dialer popup

dial.py

# Creator : Naman Tiwari (namantw)
# To run : Make sure Python 3 is installed and PyQt5 is installed
# Test : python dial.py <phone number>
# For example : 'python dial.py +9872621111'

from PyQt5.QtCore import Qt
from PyQt5.QtWidgets import (QApplication, QGridLayout, QLayout, QLineEdit,
        QSizePolicy, QToolButton, QWidget)

class Button(QToolButton):
    def __init__(self, text, parent=None):
        super(Button, self).__init__(parent)

        self.setSizePolicy(QSizePolicy.Expanding, QSizePolicy.Preferred)
        self.setText(text)

    def sizeHint(self):
        size = super(Button, self).sizeHint()
        size.setHeight(size.height() + 20)
        size.setWidth(max(size.width(), size.height()))
        return size


class Dialer(QWidget):
    NumDigitButtons = 10
    
    def __init__(self, parent=None):
        super(Dialer, self).__init__(parent)

        phone = sys.argv[1];
        try: 
            int(phone)
        except ValueError:
            phone = 'Not a number'

        self.display = QLineEdit(phone)
        self.display.setReadOnly(True)
        self.display.setAlignment(Qt.AlignRight)
        self.display.setMaxLength(15)

        font = self.display.font()
        font.setPointSize(font.pointSize() + 8)
        self.display.setFont(font)

        self.digitButtons = []
        
        for i in range(Dialer.NumDigitButtons):
            self.digitButtons.append(self.createButton(str(i),
                    self.digitClicked))

        self.backspaceButton = self.createButton("<--",
                self.backspaceClicked)
        self.clearButton = self.createButton("Clear", self.clear)
        self.callButton = self.createButton("Call", self.call)

        mainLayout = QGridLayout()
        mainLayout.setSizeConstraint(QLayout.SetFixedSize)

        mainLayout.addWidget(self.display, 0, 1, 1, 3)
        mainLayout.addWidget(self.backspaceButton, 1, 1, 1, 1)
        mainLayout.addWidget(self.clearButton, 1, 2, 1, 2)

        for i in range(1, Dialer.NumDigitButtons):
            row = ((9 - i) / 3) + 2
            column = ((i - 1) % 3) + 1
            mainLayout.addWidget(self.digitButtons[i], row, column)

        mainLayout.addWidget(self.digitButtons[0], 5, 1)
        mainLayout.addWidget(self.callButton, 5, 2, 1, 2)
        self.setLayout(mainLayout)

        self.setWindowTitle("Dialer")

    def digitClicked(self):
        clickedButton = self.sender()
        digitValue = int(clickedButton.text())

        if self.display.text() == '0' and digitValue == 0.0:
            return

        if self.display.text() == '0':  
            self.display.setText(str(digitValue))
            return

        self.display.setText(self.display.text() + str(digitValue))


    def backspaceClicked(self):
        text = self.display.text()[:-1]
        if not text:
            text = '0'

        self.display.setText(text)

    def clear(self):
        self.display.setText('0')

    def call(self):
        #Well :( ummm.... Not ready to call yet
        return

    def createButton(self, text, member):
        button = Button(text)
        button.clicked.connect(member)
        return button


if __name__ == '__main__':

    import sys

    app = QApplication(sys.argv)
    dialer = Dialer()
    dialer.show()
    sys.exit(app.exec_())