return error if TextField contains non-integers - NOT WORKING!

[jeduhi]

I am trying to validate that the characters entered in the two TextField's are ints. Instead my code is treating anything that is not an integer like a "0"

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

public class simpleCalculator {
	
	private JFrame frame;
	private JButton add, subtract, multiply, divide;
	private JLabel result;	
	private JTextField text1, text2;	
	private int b1, b2;
	
	public simpleCalculator() {
		frame = new JFrame();
		frame.setLocation(100,100);
		frame.setSize(400,400);
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		frame.setTitle("My Simple Calculator");
		
		initializeComponents();
		
		frame.pack();
		frame.setVisible(true);
	}
	
	public void initializeComponents() {
		//method to create panels. Three panels are needed for simpleCalculator
		JPanel textPanel = new JPanel();
		JPanel resultPanel = new JPanel();
		JPanel buttonPanel = new JPanel();
		
		//method to create and add text boxes to textPanel.
		text1 = new JTextField(10);
		text2 = new JTextField(10);
		textPanel.add(text1);
		textPanel.add(text2);
				
		//method to add result to resultPanel.
		result = new JLabel("Result: ");
		resultPanel.add(result);
		
		//method to create buttons.
		add = new JButton("ADD");
		subtract = new JButton("SUB");
		multiply = new JButton("MULT");
		divide = new JButton("DIV");
		
		//method to add buttons.
		buttonPanel.add(add);
		buttonPanel.add(subtract);
		buttonPanel.add(multiply);
		buttonPanel.add(divide);
		
		//initialize calculate
		calculate c = new calculate();
		
		//add ActionListener to buttons
		add.addActionListener(c);
		subtract.addActionListener(c);
		multiply.addActionListener(c);
		divide.addActionListener(c);		
		
		//method to add panels to frame.
		frame.add(textPanel, BorderLayout.PAGE_START);
		frame.add(resultPanel, BorderLayout.LINE_START);
		frame.add(buttonPanel, BorderLayout.PAGE_END);		
	}
	
	class calculate implements ActionListener {
		public void actionPerformed(ActionEvent e) {
			Object button = e.getSource();
			try {
				b1 = Integer.parseInt(text1.getText());
			}
			catch(NumberFormatException nfe) {
				result.setText("Result: ERROR");
			}
			try {
				b2 = Integer.parseInt(text2.getText());
			}
			catch(NumberFormatException nfe) {
				result.setText("Result: ERROR");
			}
			if(button == add) {
				int total = b1 + b2;
				String r = Integer.toString(total);
				result.setText("Result: " + r);
			}
			if(button == subtract) {
				int total = b1 - b2;
				String r = Integer.toString(total);
				result.setText("Result: " + r);
			}
			if(button == multiply) {
				int total = b1 * b2;
				String r = Integer.toString(total);
				result.setText("Result: " + r);
			}
			if(button == divide) {
				if(b2 == 0) {
					result.setText("Result: ERROR");
				}
				else {
					int total = b1 / b2;
					String r = Integer.toString(total);
					result.setText("Result: " + r);
				}
			}
		}
	}

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		new simpleCalculator();
	}

}

[Fubarable]

You are doing a great job of catching for number format errors, but then your method keeps right on rolling along if an error is encountered. In other words, there's nothing stopping the code beginning with

if(button == add) {

if a parsing error is encountered

I would organize things differently. Two possible ways of doing this are (in) pseudocode:

try 
  parse int for text1
  parse int for text2
catch
  notify user of error
  return out of method ***** you're not doing this


// outside of try/catch block, do rest of method's processing here

Alternatively, you could do

try 
  parse int for text1
  parse int for text2

  // do everything else that needs to be done in the method here while still in the try block
catch
  notify user of error

[Norm]

Add a boolean flag to that is set to indicate bad values in the text fields
Or exit the listener method when bad input is detected. Don't ignore the bad input and continue.

[jeduhi]

You are doing a great job of catching for number format errors, but then your method keeps right on rolling along if an error is encountered. In other words, there's nothing stopping the code beginning with

if(button == add) {

if a parsing error is encountered

I would organize things differently. Two possible ways of doing this are (in) pseudocode:

try 
  parse int for text1
  parse int for text2
catch
  notify user of error
  return out of method ***** you're not doing this


// outside of try/catch block, do rest of method's processing here

Alternatively, you could do

try 
  parse int for text1
  parse int for text2

  // do everything else that needs to be done in the method here while still in the try block
catch
  notify user of error

Thank you so much! I was not returning out of the catch. Once I put a return in everything works as it should as far as I can tell.