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How to add JTextField whenever the button is clicked?

I am practising Java Swing and I am trying to create a GPA calculator. I am having a hard time with my code, how can I add text fields whenever the JButton "add" is clicked? I also want the text fields to align vertically when the button is clicked. Should I use a layout or something?
You can check my screenshot as well.
Here is my code:
import java.awt.event.ActionEvent;
import javax.swing.*;
public class gwa implements ActionListener, java.awt.event.ActionListener{
public static void main(String[] args) {
JFrame frame = new JFrame();
JPanel panel = new JPanel();
//button
JButton buttonAdd = new JButton("Add");
buttonAdd.setBounds(30, 30, 80, 34);
buttonAdd.addActionListener(new gwa());
//textfield
JTextField gradeField = new JTextField();
gradeField.setBounds(150, 30, 100, 35);
JTextField unitsField = new JTextField();
unitsField.setBounds(300, 30, 100, 35);
//panel
panel.setLayout(null);
panel.add(buttonAdd);
panel.add(gradeField);
panel.add(unitsField);
//frame
frame.add(panel);
frame.setSize(500,500);
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
#Override
public void actionPerformed(ActionEvent e) {
}

One way – but not the only way – is to use GridBagLayout.
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextField;
public class GwaAdder {
private static final int COLUMNS = 10;
private GridBagConstraints gbc;
private JPanel textFieldsPanel;
private void addTextField(ActionEvent event) {
JTextField textField = new JTextField(COLUMNS);
gbc.gridy++;
textFieldsPanel.add(textField, gbc);
textFieldsPanel.revalidate();
textFieldsPanel.repaint();
}
private void createAndDisplayGui() {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(createTextFieldsPanel(), BorderLayout.CENTER);
frame.add(createButtons(), BorderLayout.PAGE_END);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
private JPanel createButtons() {
JPanel panel = new JPanel();
JButton button = new JButton("Add");
button.addActionListener(this::addTextField);
panel.add(button);
return panel;
}
private JScrollPane createTextFieldsPanel() {
textFieldsPanel = new JPanel(new GridBagLayout());
gbc = new GridBagConstraints();
gbc.gridy = 0;
JTextField textField = new JTextField(COLUMNS);
textFieldsPanel.add(textField, gbc);
JScrollPane scrollPane = new JScrollPane(textFieldsPanel);
scrollPane.setPreferredSize(new Dimension(140, 200));
return scrollPane;
}
public static void main(String[] args) {
EventQueue.invokeLater(() -> new GwaAdder().createAndDisplayGui());
}
}
The ActionListener is implemented using method references. When you change the GUI after it is initially displayed (as the above code does in method addTextField), you usually need to call method revalidate (in class javax.swing.JComponent) followed by method repaint (in class java.awt.Component).
How it looks when I run the above code:

You should first give your button's Action event the panel, and then do the Action
My English is not good, so I use translation software to answer, please forgive me

Switching Two JPanels on same JFrame [duplicate]

I seem to not be able to find a way to get my code to work.
I am making a program and until now everything was working, i have some buttons and they do what they should.
But now i added a button that when a user click it, it should close the current GUI and open a new one.
I also want to point out that i created a new class for this new GUI.
The other GUI class that i want to call is the GuiCrafting, in that class the GUI is also all coded, and works if i call it on the Main.
My question is what do i type here (I tried a lot of things like dispose() etc but i just get error messages) :
public void actionPerformed(ActionEvent event) {
if( str.equals("Crafting")){
//insert code to call the GuiCrafting class and open his GUI
}
Thanks in advance and if you need something more please let me know.

Multiple JFrames are frowned upon as you can read about here and here
Perhaps what you want to use is a CardLayout which manages two or more components (usually JPanel instances) that share the same display space.
After clicking the button "Goto Card 2"
TestApp.java:
import java.awt.BorderLayout;
import java.awt.CardLayout;
import java.awt.event.ActionEvent;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class TestApp {
final static String CARD1 = "Card1";
final static String CARD2 = "Card2";
public TestApp() {
initComponents();
}
public static void main(String[] args) {
SwingUtilities.invokeLater(TestApp::new);
}
private void initComponents() {
JFrame frame = new JFrame("TestApp");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// create the panel that contains the "cards".
JPanel cards = new JPanel(new CardLayout());
// card 1 components
JButton buttonGotoCard2 = new JButton("Goto Card 2");
buttonGotoCard2.addActionListener((ActionEvent e) -> {
CardLayout cl = (CardLayout) (cards.getLayout());
cl.show(cards, CARD2);
});
// create card 1
JPanel card1 = new JPanel();
card1.add(new JLabel("Card 1"));
card1.add(buttonGotoCard2);
// card 2 components
JButton buttonGotoCard1 = new JButton("Goto Card 1");
buttonGotoCard1.addActionListener((ActionEvent e) -> {
CardLayout cl = (CardLayout) (cards.getLayout());
cl.show(cards, CARD1);
});
// create card 2
JPanel card2 = new JPanel();
card2.add(new JLabel("Card 2"));
card2.add(buttonGotoCard1);
// add cards to cards panel
cards.add(card1, CARD1);
cards.add(card2, CARD2);
frame.getContentPane().add(cards, BorderLayout.CENTER);
frame.pack();
frame.setVisible(true);
}
}
There is also a JDialog which could be what you want.
HOWEVER
You can easily do something like that (Open a JFrame from another If you must):
TestApp.java:
import java.awt.event.ActionEvent;
import java.awt.event.WindowAdapter;
import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.border.EmptyBorder;
public class TestApp {
public TestApp() {
initComponents();
}
public static void main(String[] args) {
SwingUtilities.invokeLater(TestApp::new);
}
private void initComponents() {
JFrame mainFrame = new JFrame();
mainFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel panel = new JPanel();
panel.setLayout(new BoxLayout(panel, BoxLayout.Y_AXIS));
panel.setBorder(new EmptyBorder(10, 10, 10, 10));
JLabel label = new JLabel("JFrame 1");
JButton button = new JButton("Open JFrame 2");
button.addActionListener((ActionEvent e) -> {
this.showNewJFrame(new WindowAdapter() {
#Override
public void windowClosing(java.awt.event.WindowEvent e) {
// here we listen for the second JFrame being closed so we can bring back the main JFrame
mainFrame.setVisible(true);
}
});
// hide the main JFrame
mainFrame.setVisible(false);
});
panel.add(label);
panel.add(button);
mainFrame.add(panel);
mainFrame.pack();
mainFrame.setVisible(true);
}
private void showNewJFrame(WindowAdapter windowAdapter) {
JFrame frame2 = new JFrame();
frame2.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE); // we dont wnat to exit when this JFrame is closed
JPanel panel2 = new JPanel();
panel2.setLayout(new BoxLayout(panel2, BoxLayout.Y_AXIS));
panel2.setBorder(new EmptyBorder(10, 10, 10, 10));
JLabel label2 = new JLabel("JFrame 2");
panel2.add(label2);
frame2.add(panel2);
frame2.addWindowListener(windowAdapter);
frame2.pack();
frame2.setVisible(true);
}
}
This produces:
and when the "Open JFrame 2" is clicked:
and when JFrame 2 is closed it brings back the main JFrame via the WindowAdapter#windowClosing.

Can't get the buttons to be on the center right position

I'm trying to figure out how to position my buttons in the center right position. I added what Ive done so far and I'll add a drawing of how I want it to be.
I'm trying to understand how to determine the position I want in Swing, can't really understand the advantages of each layout.
My code so far:
package Game;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.GridLayout;
import java.awt.Image;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JToolBar;
import javax.swing.Timer;
public class MainWindow extends JFrame implements ActionListener {
private JButton exit;
private JButton start_Game;
private ImageIcon puzzleBackground;
// private JLabel back_Label;
// private GridBagConstraints grid = new GridBagConstraints();
private JPanel menu;
public MainWindow()
{
super("Welcome");
setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
setSize(450,300);
setLocationRelativeTo(null);
this.setLayout(new FlowLayout(FlowLayout.RIGHT));
menu = new JPanel();
menu.setLayout(new BorderLayout());
//setResizable(false);
//===== Background =====
puzzleBackground = new ImageIcon("MyBackground.jpg");
setContentPane(new JLabel(puzzleBackground));
exit = new JButton("Exit");
menu.add(exit, BorderLayout.CENTER);
exit.addActionListener(this);
start_Game = new JButton("Start to play");
menu.add(start_Game, BorderLayout.SOUTH);
exit.addActionListener(this);
start_Game.addActionListener(this);
//
// back_Label = new JLabel(puzzleBackground);
// back_Label.setLayout(new BorderLayout());
//===== Buttons =====
// back_Label.add(exit,BorderLayout.CENTER);
//
// back_Label.add(start_Game,BorderLayout.EAST);
//
add(menu);
setVisible(true);
}
public static void main(String args[])
{
MainWindow a = new MainWindow();
}
#Override
public void actionPerformed(ActionEvent e) {
if(e.getSource() == exit)
{
System.exit(0);
}
else
{
//open start up window.
}
}
}

A better way to add a BG image is to use a custom painted JPanel. Then set the layout of the panel and add other panels or components to it. Note that here the buttons are not appearing largely because they are being added to a JLabel.
Here is an alternative that works along the same lines, with the red panel being the panel which custom paints the background image and the menu panel being set to transparent (look for the opaque method).
import java.awt.*;
import java.awt.image.*;
import javax.swing.*;
import javax.swing.border.*;
public class MainWindow extends JFrame {
private JPanel menu;
private JPanel contentPane = new JPanel(new BorderLayout(4,4));
public MainWindow() {
super("Welcome");
setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
//setSize(450, 300); // use pack() instead
setContentPane(contentPane);
contentPane.setBorder(new EmptyBorder(8,8,8,8));
contentPane.setBackground(Color.RED);
contentPane.add(new JLabel(new ImageIcon(
new BufferedImage(400,200,BufferedImage.TYPE_INT_RGB))));
menu = new JPanel(new GridLayout(0,1,10,10));
menu.add(new JButton("Exit"), BorderLayout.CENTER);
menu.add(new JButton("Start to play"), BorderLayout.SOUTH);
JPanel menuCenterPanel = new JPanel(new GridBagLayout());
menuCenterPanel.add(menu);
add(menuCenterPanel, BorderLayout.LINE_END);
pack();
setLocationRelativeTo(null); // do AFTER pack()
setMinimumSize(getSize());
setVisible(true);
}
public static void main(String args[]) {
MainWindow a = new MainWindow();
}
}

So, your basic problem boils down the following lines...
this.setLayout(new BorderLayout());
//...
//===== Background =====
puzzleBackground = new ImageIcon("MyBackground.jpg");
setContentPane(new JLabel(puzzleBackground));
Can you tell me what the layout manager in use actually is now? Wrong. The layout manager is now null, because JLabel doesn't actually have a default layout manager.
So, the "simple" answer would be to move the setLayout call to below the setContentPane call, but this would be a short sighted answer, as JLabel calculates it's preferred based on the icon and text properties only, not it's contents of child components.
A better solution would be to do something demonstrated in How to set a background picture in JPanel (see the second example)
This means that if the image is smaller then the required space, the components will disappear off the screen.
I went through and cleaned up the code slightly, only with the intention of getting the layout to work
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class MainWindow extends JFrame implements ActionListener {
private JButton exit;
private JButton start_Game;
private JPanel menu;
public MainWindow() {
super("Welcome");
setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
setLocationRelativeTo(null);
this.setLayout(new BorderLayout());
menu = new JPanel();
menu.setLayout(new GridBagLayout());
exit = new JButton("Exit");
exit.addActionListener(this);
start_Game = new JButton("Start to play");
exit.addActionListener(this);
start_Game.addActionListener(this);
GridBagConstraints gbc = new GridBagConstraints();
gbc.weightx = 1;
gbc.fill = gbc.HORIZONTAL;
gbc.gridwidth = GridBagConstraints.REMAINDER;
menu.add(exit, gbc);
menu.add(start_Game, gbc);
// This is just a filler, it can be removed, but it helps prove the point
add(new JPanel() {
#Override
public Dimension getPreferredSize() {
return new Dimension(200, 200);
}
});
add(menu, BorderLayout.EAST);
pack();
setVisible(true);
}
public static void main(String args[]) {
MainWindow a = new MainWindow();
}
#Override
public void actionPerformed(ActionEvent e) {
if (e.getSource() == exit) {
System.exit(0);
} else {
//open start up window.
}
}
}
I'd also like to point out that extending directly from JFrame is also short sighted, it's locking you into a single use container and you're not actually adding any new functionality to the class.
Example of better structure...
The following is a simple example of a possibly better structure. It's missing the concept of a "controller", which controls stuff and "model" which maintains the state information which is used by the UI to display "stuff", but gives a starting point
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class Main {
public static void main(String args[]) {
new Main();
}
public Main() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
JFrame frame = new JFrame("Welcome");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new MainPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class MainPane extends JPanel {
public MainPane() {
setLayout(new BorderLayout());
// This is just a filler, it can be removed, but it helps prove the point
add(new JPanel() {
#Override
public Dimension getPreferredSize() {
return new Dimension(200, 200);
}
});
add(new MenuPane(), BorderLayout.EAST);
}
}
public class MenuPane extends JPanel {
private JButton exit;
private JButton start_Game;
private JPanel menu;
public MenuPane() {
menu = new JPanel();
menu.setLayout(new GridBagLayout());
ActionHandler actionHandler = new ActionHandler();
exit = new JButton("Exit");
exit.addActionListener(actionHandler);
start_Game = new JButton("Start to play");
start_Game.addActionListener(actionHandler);
GridBagConstraints gbc = new GridBagConstraints();
gbc.weightx = 1;
gbc.fill = gbc.HORIZONTAL;
gbc.gridwidth = GridBagConstraints.REMAINDER;
menu.add(exit, gbc);
menu.add(start_Game, gbc);
}
public class ActionHandler implements ActionListener {
#Override
public void actionPerformed(ActionEvent e) {
if (e.getSource() == exit) {
System.exit(0);
} else {
//open start up window.
// This should be used to notifiy a controller class
// that some new action needs to take place, the controller
// is then responsible for making it happen
}
}
}
}
}

Doing UI in Java is not advised, but ignoring that.
You get (calculate) the height and width of the screen. Then start drawing buttons depending on that. Drawing a button on screens 50% of pixel value width and 50% of pixel value of height will center the button.
Simply crate buttons with variable location that is calculated from main screen px size and place them where ever you want.

swing and GUI components not appearing

I'm a complete noobie with swing. I'm trying to set a few JPanels and TextAreas to show up but after spending 2 days reading the APIs and trying to add panels to frames and textareas to panels and nothing is showing up.. I'm utterly confused. If anyone could explain how is the best way to do this I would be very grateful
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
public class GUI {
public static void main(String[] args) {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
frame.setLayout(new FlowLayout()); // J FRAME
JPanel panel = new JPanel(); // first panel on the left
panel.setLayout(new BoxLayout(panel, 1));
// frame.getContentPane().setBackground(Color.red);
frame.add(panel);
JLabel surname = new JLabel();
JLabel initial = new JLabel();
JLabel ext = new JLabel();
surname.setOpaque(true);
initial.setOpaque(true);
ext.setOpaque(true);
frame.add(surname);
panel.add(initial);
panel.add(ext);
JTextArea table = new JTextArea();
table.setEditable(false);
panel.add(table);
table.setVisible(true);

You're adding stuff to the JFrame after it's already visible. If you do that, you need to revalidate your JFrame so it knows to redo its layout.
You could also just wait to show your JFrame until after you've added everything.
Edit: Here is an example program that shows what I'm talking about. Try running this, then take out the call to revalidate() to see the difference.
import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
public class Test {
public static void main(String[] args) {
final JFrame frame = new JFrame("Test");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
final JButton show = new JButton("Show");
show.addActionListener(new ActionListener(){
#Override
public void actionPerformed(ActionEvent showE) {
frame.add(new JLabel("Test"), BorderLayout.SOUTH);
frame.revalidate(); //tell the JFrame to redo its layout!
}
});
frame.add(show);
frame.setSize(200, 200);
frame.setVisible(true);
}
}

You are adding an empty elements like:
JLabel surname = new JLabel();
Your elements is already added but have nothing to be display.
Try :
JLabel surname = new JLabel("UserName");
JLabel initial = new JLabel("Iinitial");
JLabel ext = new JLabel("Ext");
JTextArea table = new JTextArea(10, 5);

How to make radio buttons change text dynamically in Java

I'm fairly new to GUI. I'm trying to make it so that depending on which radio button is selected, a JLabel changes its value. For example, if "id" is selected, it'll display "http://steamcommunity.com/id/" and if "profile" is selected, it'll display "http://steamcommunity.com/profiles/". I have some code up and running and it's nearly complete:
package sgt;
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import javax.swing.BorderFactory;
import javax.swing.ButtonGroup;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JRadioButton;
import javax.swing.JTextField;
public class RadioButtonPrompt extends JPanel
implements ActionListener {
private static final long serialVersionUID = 1L;
static String idString = "ID";
static String profileString ="Profile";
static String type = idString;
public RadioButtonPrompt() {
super(new BorderLayout());
// Create radio buttons.
JRadioButton idButton = new JRadioButton(idString, true);
idButton.setMnemonic(KeyEvent.VK_I);
idButton.setActionCommand(idString);
JRadioButton profileButton = new JRadioButton(profileString);
profileButton.setMnemonic(KeyEvent.VK_P);
profileButton.setActionCommand(profileString);
// Group radio buttons.
ButtonGroup group = new ButtonGroup();
group.add(idButton);
group.add(profileButton);
idButton.addActionListener(this);
profileButton.addActionListener(this);
JPanel radioPanel = new JPanel(new GridLayout(0, 1));
radioPanel.add(idButton);
radioPanel.add(profileButton);
JPanel textPanel = new JPanel ();
JLabel URL = new JLabel(setJLabelValue());
JTextField text = new JTextField("sampletextfield");
text.setPreferredSize(new Dimension(100, 20));
textPanel.add(URL);
textPanel.add(text);
JPanel buttonPanel = new JPanel(new GridLayout(1, 0));
JButton submit = new JButton("Submit");
submit.setMnemonic(KeyEvent.VK_S);
buttonPanel.add(submit);
add(radioPanel, BorderLayout.LINE_START);
add(textPanel, BorderLayout.CENTER);
add(buttonPanel, BorderLayout.PAGE_END);
setBorder(BorderFactory.createCompoundBorder());
}
private String setJLabelValue() {
if (type.equals("ID")) {
return "http://steamcommunity.com/id/";
}
return "http://steamcommunity.com/profiles/";
}
public void actionPerformed(ActionEvent e) {
// Returns either "Profile" or "ID"
type = ((JRadioButton)e.getSource()).getText();
System.out.println(type);
}
private static void createAndShowGUI() {
JFrame frame = new JFrame("Steam Game Tracker");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JComponent newContentPane = new RadioButtonPrompt();
newContentPane.setOpaque(true); //content panes must be opaque
frame.setContentPane(newContentPane);
// Display the window.
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args) {
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});
}
}

Take a look at this SO thread.

in actionPerformed() you need to textpanel.setText() to whatever you want based on which button was clicked. I'm guessing at the method name, haven't done any UI stuff with Java for a while.