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Thread: Help on exit button/panel

  1. #1
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    Default 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);
    	            }
    	        }
    Attached Images Attached Images


  2. #2
    Super Moderator curmudgeon's Avatar
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    Default Re: Help on exit button/panel

    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.

  3. #3
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    Default Re: Help on exit button/panel

    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.

  4. #4
    Super Moderator Norm's Avatar
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    Default Re: Help on exit button/panel

    exit.addActuonListener(new ExitClass()); and we get error message saying cannot find symbol
    Check your spelling for that class name: ExitClass. Where is it defined?
    If you don't understand my answer, don't ignore it, ask a question.

  5. #5
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    Default Re: Help on exit button/panel

    what do you mean by where is it defined?

  6. #6
    Super Moderator Norm's Avatar
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    Default Re: Help on exit button/panel

    The compiler can not find the definition for the class: ExitClass.
    Where is the ExitClass.class or the ExitClass.java file located?

    See the tutorial for how to declare/define a class:
    Declaring Classes (The Java™ Tutorials > Learning the Java Language > Classes and Objects)
    If you don't understand my answer, don't ignore it, ask a question.

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