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Writing Calculator Program in Swing

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In this tutorial we are providing you an example which illustrates you how to a create calculator in Swing with the source code and screen shot.

Writing Calculator Program in Swing

     

In this tutorial we are providing you an example which illustrates you how to a create calculator in Swing with the source code and screen shot.

For developing a small calculator program in swing we need two different classes 

1) SwingCalculator.java
2) Calculator.java

The SwingCalculator.java calls the Calculator.java class by JFrame frame = new Calculator(). All the methods and actions are to be performed in Calculator.java class.

Calculator Code in Java Swing



Please save the code as SwingCalculator.java

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;

class SwingCalculator {
 public static void main(String[] args) {
  JFrame frame = new Calculator();
  frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  frame.setVisible(true);
  }
}


Here is the code of Calculator.java

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;

  class Calculator extends JFrame {
  private final Font BIGGER_FONT = new Font("monspaced",
  Font.PLAIN, 
20);
  private JTextField textfield; 
  private boolean number = true;  
  private String  equalOp  = "=";  
  private CalculatorOp op = new CalculatorOp(); 

  public Calculator() {
  textfield = new JTextField("0"12);
  textfield.setHorizontalAlignment(JTextField.RIGHT);
  textfield.setFont(BIGGER_FONT);
  
  ActionListener numberListener = new NumberListener();
  String buttonOrder = "1234567890 ";
  JPanel buttonPanel = new JPanel();
  buttonPanel.setLayout(new GridLayout(4444));
  for (int i = 0; i < buttonOrder.length(); i++) {
  String key = buttonOrder.substring(i, i+1);
  if (key.equals(" ")) {
  buttonPanel.add(new JLabel(""));
  else {
  JButton button = new JButton(key);
  button.addActionListener(numberListener);
  button.setFont(BIGGER_FONT);
  buttonPanel.add(button);
  }
  }
  ActionListener operatorListener = new OperatorListener();
  JPanel panel = new JPanel();
  panel.setLayout(new GridLayout(4444));
  String[] opOrder = {"+""-""*""/","=","C"};
 for (int i = 0; i < opOrder.length; i++) {
  JButton button = new JButton(opOrder[i]);
  button.addActionListener(operatorListener);
  button.setFont(BIGGER_FONT);
  panel.add(button);
  }
 JPanel pan = new JPanel();
  pan.setLayout(new BorderLayout(44));
  pan.add(textfield, BorderLayout.NORTH );
  pan.add(buttonPanel , BorderLayout.CENTER);
  pan.add(panel , BorderLayout.EAST  );
  this.setContentPane(pan);
  this.pack();
  this.setTitle("Calculator");
  this.setResizable(false);
  }
  private void action() {
  number = true
  textfield.setText("0");
  equalOp  = "=";
  op.setTotal("0");
  }
  class OperatorListener implements ActionListener {
  public void actionPerformed(ActionEvent e) {
  if (number) {
  action();
  textfield.setText("0");
  else {
  number = true
  String displayText = textfield.getText();
  if (equalOp.equals("=")) {
  op.setTotal(displayText);
  else if (equalOp.equals("+")) {
  op.add(displayText);
  else if (equalOp.equals("-")) {
  op.subtract(displayText);
  else if (equalOp.equals("*")) {
  op.multiply(displayText);
  else if (equalOp.equals("/")) {
  op.divide(displayText);
  }
 textfield.setText("" + op.getTotalString());
 equalOp = e.getActionCommand();
  }
 }
 }
  class NumberListener implements ActionListener {
  public void actionPerformed(ActionEvent event) {
  String digit = event.getActionCommand(); 
  if (number) {
  textfield.setText(digit);
  number = false;
  else {
 textfield.setText(textfield.getText() + digit);
  }
  }
  }
  public class CalculatorOp {
  
private int total; 
public CalculatorOp() {
  total = 0;
  }
 public String getTotalString() {
  return ""+total;
  }
 public void setTotal(String n) {
  total = convertToNumber(n);
  }
 public void add(String n) {
  total += convertToNumber(n);
 }
 public void subtract(String n) {
  total -= convertToNumber(n);
  }
 public void multiply(String n) {
  total *= convertToNumber(n);
  }
   public void divide(String n) {
  total /= convertToNumber(n);
  }
 private int convertToNumber(String n) {
  return Integer.parseInt(n);
  }
}
}

 
The constructor new CalculatorOp() calls the CalculatorOp class. The Swing component JTextField is used to create textbox on which calculation is to be performed. JPanel arranges the numeric buttons in a panel. JButton is used to perform an action. OperatorListener class is called to perform action on operators, i.e, '+,-,*,/,='. The class NumberListener is called for numbers 0 to 9.


Output will be displayed as:


Download Source Code

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Posted on: September 12, 2008

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Comments:29
glora
June 19, 2012
programming l

i like programming
Dilu
July 23, 2012
Error

Exception error is generated
P.M.MANJUNATH
August 9, 2012
java swings

i love this website...... i am happy to seen this website.. becoz i need to learn more in java through this valuable site.. thank you!!!!!!!!
Sanket
November 10, 2012
Great code

Code is very easy to implement. It is also short. Thanks.
erika ortega
November 25, 2012
hdh

i want a basic codes ... i want to lern more
adeela azam
May 28, 2014
student

plz explain each line of code bcz i don't know some classes.plz help me..
Preet
March 27, 2014
Codes with explanations

Can u tell me the explanations with codes so that i'll come to know the whole code what is used to create a calculator ??
Preet
March 27, 2014
functions of code explanation

Can you explain each functions of code of swing calculator ??
praveen kumar
September 14, 2012
clarification

send a simple and easy program for scientific calculator using swing in java coding
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