Thread: Help on exit button/panel

Prob1.JPG
As You can See the code works perfectly and we were able to put a exit button/panel on it

here is the code

import java.awt.*;
import javax.swing.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
 
import javax.swing.*;
public class Calculator {
	JButton add,divide,multiply,sub,exit;
	JTextField num1,num2;
	JLabel ans;
	public Calculator(){
		JFrame frame = new JFrame("Calculator - Rosopa");
		num1 = new JTextField (10);
		ans = new JLabel("");
		num2 = new JTextField (9);
		add = new JButton ("+");
		divide = new JButton("/");
		multiply = new JButton("X");
		sub = new JButton ("-");
		exit = new JButton ("EXIT");
		frame.setVisible(true);
		frame.setBounds(500, 200, 290, 210);
		frame.setLayout(new GridLayout(0,2,1,1));
		frame.add(new JLabel("First Number: "));
		frame.add(num1);
		frame.add(new JLabel("Second Number: "));
		frame.add(num2);
		frame.add(new JLabel("Answer: "));
		frame.add(ans);
		frame.add(add);
		frame.add(sub);
		frame.add(multiply);
		frame.add(divide);
		frame.add(exit);
		add.addActionListener(new HandlerClass());
		sub.addActionListener(new HandlerClass());
		divide.addActionListener(new HandlerClass());
		multiply.addActionListener(new HandlerClass());
 		exit.addActionListener(new HandlerClass());
 
	}
	public static void main(String[] args) {
			new Calculator();
 
	}
 
public class HandlerClass implements ActionListener{
		public void actionPerformed(ActionEvent ae){
			try{
			int fnum = Integer.parseInt(num1.getText());
			int snum = Integer.parseInt(num2.getText());
			if(ae.getSource()== add){
				ans.setText(String.valueOf(fnum+snum));
			}
			else if(ae.getSource()== sub){
				ans.setText(String.valueOf(fnum-snum));
			}
			else if(ae.getSource()== multiply){
				ans.setText(String.valueOf(fnum*snum));
			}
			else{
				ans.setText(String.valueOf(fnum/snum));
			}
			}catch(Exception e)
			{
 
				JOptionPane.showMessageDialog(null, "Please enter a valid number");
 
				e.printStackTrace();
 
			}
			}
 
	}
}

Our Problem now is that whenever we click the "EXIT" button/panel to end the program we get a message saying "PLEASE ENTER A VALID NUMBER" As Shown Below

Prob2.JPG

We tried putting some codes for the "EXIT" button but we still get the same message ("PLEASE ENTER A VALID NUMBER")

import java.awt.*;
import javax.swing.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
 
import javax.swing.*;
public class Calculator {
	JButton add,divide,multiply,sub,exit;
	JTextField num1,num2;
	JLabel ans;
	public Calculator(){
		JFrame frame = new JFrame("Calculator - Rosopa");
		num1 = new JTextField (10);
		ans = new JLabel("");
		num2 = new JTextField (9);
		add = new JButton ("+");
		divide = new JButton("/");
		multiply = new JButton("X");
		sub = new JButton ("-");
		exit = new JButton ("EXIT");
		frame.setVisible(true);
		frame.setBounds(500, 200, 290, 210);
		frame.setLayout(new GridLayout(0,2,1,1));
		frame.add(new JLabel("First Number: "));
		frame.add(num1);
		frame.add(new JLabel("Second Number: "));
		frame.add(num2);
		frame.add(new JLabel("Answer: "));
		frame.add(ans);
		frame.add(add);
		frame.add(sub);
		frame.add(multiply);
		frame.add(divide);
		frame.add(exit);
		add.addActionListener(new HandlerClass());
		sub.addActionListener(new HandlerClass());
		divide.addActionListener(new HandlerClass());
		multiply.addActionListener(new HandlerClass());
 		exit.addActionListener(new HandlerClass());
 
	}
	public static void main(String[] args) {
			new Calculator();
 
	}
 
public class HandlerClass implements ActionListener{
		public void actionPerformed(ActionEvent ae){
			try{
			int fnum = Integer.parseInt(num1.getText());
			int snum = Integer.parseInt(num2.getText());
			if(ae.getSource()== add){
				ans.setText(String.valueOf(fnum+snum));
			}
			else if(ae.getSource()== sub){
				ans.setText(String.valueOf(fnum-snum));
			}
			else if(ae.getSource()== multiply){
				ans.setText(String.valueOf(fnum*snum));
			}
			else{
				ans.setText(String.valueOf(fnum/snum));
			}
			}catch(Exception e)
			{
 
				JOptionPane.showMessageDialog(null, "Please enter a valid number");
 
				e.printStackTrace();
 
			}
			}
 
	}
}
 
 
 
 
 
        	  class ExitButtonHandler implements ActionListener
	        {
	            public void actionPerformed( ActionEvent e)
	            {
	                System.exit(0);
	            }
	        }

You're trying to parse numbers even if exit is called causing the exception to be thrown before exiting can occur. A problem is that your Handler class is trying to do too much, trying to handle several buttons with completely distinct functions. I'd recommend a separate handler for each distinct button function such as an ExitHandler class for your exit button.

we already tried that by putting exit.addActuonListener(new ExitClass()); and we get error message saying cannot find symbol and sometimes illegal start of public class.

what do you mean by where is it defined?