Swing App Currency Converter 1.0

Code:

import javax.swing.*;

import javax.swing.text.PlainDocument;

import java.awt.*;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import java.text.*;



/**

 * Currency Converter 1.0

 * Written by: Josh

 * Date: 11/27/13

 */

public class GUIMain implements ActionListener {

    //Declare variables for widgets

    private JLabel convert;

    private JLabel usDollars;

    private JLabel result;

    private JTextField usAmount;

    private JComboBox currency;

    private JButton submit;



    //Set up content for combo box

    private String[] money = {"Euro", "Japanese Yen", "Canadian Dollars", "Korean Won", "Mexican Pesos"};



    //Declare constants for currency conversion

    public static final double EURO = 0.74;

    public static final double YEN = 100.41;

    public static final double CANADIAN = 1.05;

    public static final double WON = 1062.10;

    public static final double PESOS = 13.11;



    //Main function

    public static void main(String[] args){

        GUIMain gui = new GUIMain();

        gui.go();

    }



    //Set up GUI

    public void go() {

        //Configure widgets

        convert = new JLabel("Convert:");

        usAmount = new JTextField(10);

        usDollars = new JLabel("U.S. dollars to:");

        result = new JLabel("");

        submit = new JButton("OK");

        submit.addActionListener(this);

        currency = new JComboBox(money);

        currency.setSelectedIndex(4);



        //Create a new Layout

        FlowLayout layout = new FlowLayout();



        //Create panel and add widgets

        JPanel container = new JPanel();

        container.add(convert);

        container.add(usAmount);

        container.add(usDollars);

        container.add(currency);

        container.add(submit);

        container.add(result);

        container.setLayout(layout);

        container.setBorder(BorderFactory.createEmptyBorder(15,15,15,15));

        container.setComponentOrientation(ComponentOrientation.LEFT_TO_RIGHT);



        //Create frame, set properties, and add panel

        JFrame frame = new JFrame();

        frame.setTitle("Currency Converter 1.0");

        frame.setSize(440, 300);

        frame.getContentPane().add(container);

        frame.setLocationRelativeTo(null);

        frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);

        frame.setResizable(false);

        frame.setVisible(true);

    }



    //Convert selected currency and display

    @Override

    public void actionPerformed(ActionEvent e) {

        DecimalFormat df = new DecimalFormat("#.##");



        try {

            double oldAmount = Double.parseDouble(usAmount.getText());

            int index = currency.getSelectedIndex();

            Double newAmount = 0.0;



            switch (index){

                case 0: newAmount = oldAmount * EURO;

                        break;

                case 1: newAmount = oldAmount * YEN;

                        break;

                case 2: newAmount = oldAmount * CANADIAN;

                        break;

                case 3: newAmount = oldAmount * WON;

                        break;

                case 4: newAmount = oldAmount * PESOS;

                        break;

            }

                result.setText(" " + df.format(newAmount));

        } catch (Exception ex){

            result.setText("Error: Please enter a valid currency amount");

        }

    }

}

Code:

import javax.swing.*;

import javax.swing.text.PlainDocument;

import java.awt.*;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import java.text.*;



/**

 * Currency Converter 1.0

 * Written by: Josh

 * Date: 11/27/13

 */

public class GUIMain implements ActionListener {

    //Declare variables for widgets

    private JLabel convert;

    private JLabel usDollars;

    private JLabel result;

    private JTextField usAmount;

    private JComboBox currency;

    private JButton submit;



    //Set up content for combo box

    private String[] money = {"Euro", "Japanese Yen", "Canadian Dollars", "Korean Won", "Mexican Pesos"};



    //Declare constants for currency conversion

    public static final double EURO = 0.74;

    public static final double YEN = 100.41;

    public static final double CANADIAN = 1.05;

    public static final double WON = 1062.10;

    public static final double PESOS = 13.11;



    //Main function

    public static void main(String[] args){

        GUIMain gui = new GUIMain();

        gui.go();

    }



    //Set up GUI

    public void go() {

        //Configure widgets

        convert = new JLabel("Convert:");

        usAmount = new JTextField(10);

        usDollars = new JLabel("U.S. dollars to:");

        result = new JLabel("");

        submit = new JButton("OK");

        submit.addActionListener(this);

        currency = new JComboBox(money);

        currency.setSelectedIndex(4);



        //Create a new Layout

        FlowLayout layout = new FlowLayout();



        //Create panel and add widgets

        JPanel container = new JPanel();

        container.add(convert);

        container.add(usAmount);

        container.add(usDollars);

        container.add(currency);

        container.add(submit);

        container.add(result);

        container.setLayout(layout);

        container.setBorder(BorderFactory.createEmptyBorder(15,15,15,15));

        container.setComponentOrientation(ComponentOrientation.LEFT_TO_RIGHT);



        //Create frame, set properties, and add panel

        JFrame frame = new JFrame();

        frame.setTitle("Currency Converter 1.0");

        frame.setSize(440, 300);

        frame.getContentPane().add(container);

        frame.setLocationRelativeTo(null);

        frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);

        frame.setResizable(false);

        frame.setVisible(true);

    }



    //Convert selected currency and display

    @Override

    public void actionPerformed(ActionEvent e) {

        DecimalFormat df = new DecimalFormat("#.##");



        try {

            double oldAmount = Double.parseDouble(usAmount.getText());

            int index = currency.getSelectedIndex();

            Double newAmount = 0.0;



            switch (index){

                case 0: newAmount = oldAmount * EURO;

                        break;

                case 1: newAmount = oldAmount * YEN;

                        break;

                case 2: newAmount = oldAmount * CANADIAN;

                        break;

                case 3: newAmount = oldAmount * WON;

                        break;

                case 4: newAmount = oldAmount * PESOS;

                        break;

            }

                result.setText(" " + df.format(newAmount));

        } catch (Exception ex){

            result.setText("Error: Please enter a valid currency amount");

        }

    }

}