[darthjames226]

This is a swing application coded from scratch by myself. I recently started to learn swing and decided to do a project for more experience. Just thought I would share my source code with you guys in case you want to learn swing. Any feedback for improvement would be much appreciated. I would like to re-position my widgets to make it more presentably but I'm new to swing and haven't learned how to take full control of my positioning. Any suggestions?

This app converts US currency to the currency value of 5 different countries.

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"); } } }

[darthjames226]

This is a swing application coded from scratch by myself. I recently started to learn swing and decided to do a project for more experience. Just thought I would share my source code with you guys in case you want to learn swing. Any feedback for improvement would be much appreciated. I would like to re-position my widgets to make it more presentably but I'm new to swing and haven't learned how to take full control of my positioning. Any suggestions?

This app converts US currency to the currency value of 5 different countries.

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"); } } }

[Deque]

I would have used an Enum for the currency (instead of the "constants") as well as the strings related to that. It will spare you the switch-case statement.
I also suggest you use Java docs instead of just comments.

Other than that I see nothing wrong with it.

[bananamango]

Idea: Use online stats to make your converter time accurate without updating.

[Daedalus]

Although I only have very little experience with Java, your code doesn't look too bad at all. As much as I dislike Java, I do give it props for how easy it is to write GUIs using Swing.

[Coder-san]

Why eCurrency? It's Real Currency you are dealing with.
eCurrency are Paypal, and gang.

[darthjames226]

I would have used an Enum for the currency (instead of the "constants") as well as the strings related to that. It will spare you the switch-case statement.
I also suggest you use Java docs instead of just comments.

Other than that I see nothing wrong with it.

You made some very valid points. I will work on the suggestions you made. Thanks for the advice.

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Idea: Use online stats to make your converter time accurate without updating.

This is a very interesting idea. Any suggestions on how I can go about implementing this in my code?

---

Although I only have very little experience with Java, your code doesn't look too bad at all. As much as I dislike Java, I do give it props for how easy it is to write GUIs using Swing.

Thanx. I have some re-factoring to do but I'm satisfied with the results thus far. I'm going to implement a FlowLayout instead of BorderLayout to improve on the GUI. Yes I have found Java to be very convenient when designing a GUI from scratch without the using a point and click GUI designer. I prefer to code from scratch then a GUI builder. You learn a lot more that way.

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Why eCurrency? It's Real Currency you are dealing with.
eCurrency are Paypal, and gang.

You're absolutely correct and I will implement that change. I've made numerous apps in different languages which I always prefixed the title with an 'e'. However in this case it does make sense to remove it. Thanx for pointing this out.

[bananamango]

I would have used an Enum for the currency (instead of the "constants") as well as the strings related to that. It will spare you the switch-case statement.
I also suggest you use Java docs instead of just comments.

Other than that I see nothing wrong with it.

You made some very valid points. I will work on the suggestions you made. Thanks for the advice.

---

Idea: Use online stats to make your converter time accurate without updating.

This is a very interesting idea. Any suggestions on how I can go about implementing this in my code?

---

Although I only have very little experience with Java, your code doesn't look too bad at all. As much as I dislike Java, I do give it props for how easy it is to write GUIs using Swing.

Thanx. I have some re-factoring to do but I'm satisfied with the results thus far. I'm going to implement a FlowLayout instead of BorderLayout to improve on the GUI. Yes I have found Java to be very convenient when designing a GUI from scratch without the using a point and click GUI designer. I prefer to code from scratch then a GUI builder. You learn a lot more that way.

Well brief overview would be to:
Open a socket
Read some websites rss feed on currency exchanges
Use regex to sort out the numbers.

[darthjames226]

Well brief overview would be to:
Open a socket
Read some websites rss feed on currency exchanges
Use regex to sort out the numbers.

I will most definitely look into this. Thanx for the advice. :Thumbs-Up:

[bananamango]

Well brief overview would be to:
Open a socket
Read some websites rss feed on currency exchanges
Use regex to sort out the numbers.

I will most definitely look into this. Thanx for the advice. :Thumbs-Up:

No problem man, goodluck with it. Keep me informed on how you do.