Building Calculator using PyQt5 in Python
In this article we will see how we can create a calculator using PyQt5,A calculator is something used for making mathematical calculations, in particular a small electronic device with a keyboard and a visual display. below is the how the calculator will looks like
GUI implementation steps
- Create a label to show the numbers and the output and set its geometry
- Align the label text fro right side and increase the font size of it
- Create push buttons for the numbers from 0 to 9 and set their geometry in the proper order
- Create operator push button example for addition, subtraction etc
- Add a color effect to the equals button to highlight it
Back end implementation steps
- Add action to each button
- Inside the actions of each button except the equals to action, append the text of the label with the respective number or the operator
- Inside the equals to action get the text of the label and start the try except block
- Inside the try block use eval method on the label text to get the ans and set the answer to the label
- Inside the except block set “Wrong Input” as text
- For delete action make the last character removed from the label and for the clear action set the whole text to blank.
Below is the implementation
# importing libraries from PyQt5.QtWidgets import *from PyQt5 import QtCore, QtGui from PyQt5.QtGui import *from PyQt5.QtCore import * import sys class Window(QMainWindow): def __init__(self): super().__init__() # setting title self.setWindowTitle("Python ") # setting geometry self.setGeometry(100, 100, 360, 350) # calling method self.UiComponents() # showing all the widgets self.show() # method for widgets def UiComponents(self): # creating a label self.label = QLabel(self) # setting geometry to the label self.label.setGeometry(5, 5, 350, 70) # creating label multi line self.label.setWordWrap(True) # setting style sheet to the label self.label.setStyleSheet("QLabel" "{" "border : 4px solid black;" "background : white;" "}") # setting alignment to the label self.label.setAlignment(Qt.AlignRight) # setting font self.label.setFont(QFont('Arial', 15)) # adding number button to the screen # creating a push button push1 = QPushButton("1", self) # setting geometry push1.setGeometry(5, 150, 80, 40) # creating a push button push2 = QPushButton("2", self) # setting geometry push2.setGeometry(95, 150, 80, 40) # creating a push button push3 = QPushButton("3", self) # setting geometry push3.setGeometry(185, 150, 80, 40) # creating a push button push4 = QPushButton("4", self) # setting geometry push4.setGeometry(5, 200, 80, 40) # creating a push button push5 = QPushButton("5", self) # setting geometry push5.setGeometry(95, 200, 80, 40) # creating a push button push6 = QPushButton("5", self) # setting geometry push6.setGeometry(185, 200, 80, 40) # creating a push button push7 = QPushButton("7", self) # setting geometry push7.setGeometry(5, 250, 80, 40) # creating a push button push8 = QPushButton("8", self) # setting geometry push8.setGeometry(95, 250, 80, 40) # creating a push button push9 = QPushButton("9", self) # setting geometry push9.setGeometry(185, 250, 80, 40) # creating a push button push0 = QPushButton("0", self) # setting geometry push0.setGeometry(5, 300, 80, 40) # adding operator push button # creating push button push_equal = QPushButton("=", self) # setting geometry push_equal.setGeometry(275, 300, 80, 40) # adding equal button a color effect c_effect = QGraphicsColorizeEffect() c_effect.setColor(Qt.blue) push_equal.setGraphicsEffect(c_effect) # creating push button push_plus = QPushButton("+", self) # setting geometry push_plus.setGeometry(275, 250, 80, 40) # creating push button push_minus = QPushButton("-", self) # setting geometry push_minus.setGeometry(275, 200, 80, 40) # creating push button push_mul = QPushButton("*", self) # setting geometry push_mul.setGeometry(275, 150, 80, 40) # creating push button push_div = QPushButton("/", self) # setting geometry push_div.setGeometry(185, 300, 80, 40) # creating push button push_point = QPushButton(".", self) # setting geometry push_point.setGeometry(95, 300, 80, 40) # clear button push_clear = QPushButton("Clear", self) push_clear.setGeometry(5, 100, 200, 40) # del one character button push_del = QPushButton("Del", self) push_del.setGeometry(210, 100, 145, 40) # adding action to each of the button push_minus.clicked.connect(self.action_minus) push_equal.clicked.connect(self.action_equal) push0.clicked.connect(self.action0) push1.clicked.connect(self.action1) push2.clicked.connect(self.action2) push3.clicked.connect(self.action3) push4.clicked.connect(self.action4) push5.clicked.connect(self.action5) push6.clicked.connect(self.action6) push7.clicked.connect(self.action7) push8.clicked.connect(self.action8) push9.clicked.connect(self.action9) push_div.clicked.connect(self.action_div) push_mul.clicked.connect(self.action_mul) push_plus.clicked.connect(self.action_plus) push_point.clicked.connect(self.action_point) push_clear.clicked.connect(self.action_clear) push_del.clicked.connect(self.action_del) def action_equal(self): # get the label text equation = self.label.text() try: # getting the ans ans = eval(equation) # setting text to the label self.label.setText(str(ans)) except: # setting text to the label self.label.setText("Wrong Input") def action_plus(self): # appending label text text = self.label.text() self.label.setText(text + " + ") def action_minus(self): # appending label text text = self.label.text() self.label.setText(text + " - ") def action_div(self): # appending label text text = self.label.text() self.label.setText(text + " / ") def action_mul(self): # appending label text text = self.label.text() self.label.setText(text + " * ") def action_point(self): # appending label text text = self.label.text() self.label.setText(text + ".") def action0(self): # appending label text text = self.label.text() self.label.setText(text + "0") def action1(self): # appending label text text = self.label.text() self.label.setText(text + "1") def action2(self): # appending label text text = self.label.text() self.label.setText(text + "2") def action3(self): # appending label text text = self.label.text() self.label.setText(text + "3") def action4(self): # appending label text text = self.label.text() self.label.setText(text + "4") def action5(self): # appending label text text = self.label.text() self.label.setText(text + "5") def action6(self): # appending label text text = self.label.text() self.label.setText(text + "6") def action7(self): # appending label text text = self.label.text() self.label.setText(text + "7") def action8(self): # appending label text text = self.label.text() self.label.setText(text + "8") def action9(self): # appending label text text = self.label.text() self.label.setText(text + "9") def action_clear(self): # clearing the label text self.label.setText("") def action_del(self): # clearing a single digit text = self.label.text() print(text[:len(text)-1]) self.label.setText(text[:len(text)-1]) # create pyqt5 app App = QApplication(sys.argv) # create the instance of our Window window = Window() # start the app sys.exit(App.exec()) |
chevron_right
filter_none
Output :
Attention geek! Strengthen your foundations with the Python Programming Foundation Course and learn the basics.
To begin with, your interview preparations Enhance your Data Structures concepts with the Python DS Course.
