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Is there a way to reference setVisible() and dispose() from an ActionListener in a separate class file?

I'm working on a very complicated, multi-layered Swing GUI, and the main issue I'm running into right now involves having a JButton ActionListener perform setVisible() on a separate JFrame and immediately dispose() of the current JFrame. Because of the length of my code, it's important that main, both JFrames, and the ActionListener are all split into individual class files. I wrote a VERY simplified version of my problem, split into 4 tiny class files. Here they are:
File 1:
import javax.swing.*;
public class Test {
public static void main(String[] args) {
JFrame g1 = new GUI1();
g1.pack();
g1.setLocation(200,200);
g1.setVisible(true);
JFrame g2 = new GUI2();
g2.pack();
g2.setLocation(400,200);
g2.setVisible(false);
}
}
File 2:
import javax.swing.*;
public class GUI1 extends JFrame {
JPanel panel;
JButton button;
public GUI1() {
super("GUI1");
setDefaultCloseOperation(EXIT_ON_CLOSE);
panel = new JPanel();
button = new JButton("Create GUI2");
button.addActionListener(new Listener());
add(panel);
add(button);
}
}
File 3:
import javax.swing.*;
public class GUI2 extends JFrame {
JPanel panel;
JLabel label;
public GUI2() {
super("GUI2");
setDefaultCloseOperation(EXIT_ON_CLOSE);
panel = new JPanel();
label = new JLabel("I'm alive!");
add(panel);
add(label);
}
}
File 4:
import java.awt.event.*;
public class Listener implements ActionListener {
public void actionPerformed(ActionEvent e) {
GUI2.setVisible(true);
GUI1.dispose();
}
}
As you can see, the only function of the ActionListener is to set GUI2 to visible and dispose of GUI1, but it runs the error "non-static method (setVisible(boolean) and dispose()) cannot be referenced from a static context". I figure this is because both methods are trying to reference objects that were created in main, which is static. My confusion is how to get around this, WITHOUT combining everything into one class.
Any suggestions? Thanks!
EDIT:
Here's the above code compiled into one file... although it returns the exact same error.
import javax.swing.*;
import java.awt.event.*;
public class Test {
public static void main(String[] args) {
JFrame g1 = new GUI1();
g1.pack();
g1.setLocation(200,200);
g1.setVisible(true);
JFrame g2 = new GUI2();
g2.pack();
g2.setLocation(400,200);
g2.setVisible(false);
}
}
class GUI1 extends JFrame {
JPanel panel;
JButton button;
public GUI1() {
super("GUI1");
setDefaultCloseOperation(EXIT_ON_CLOSE);
panel = new JPanel();
button = new JButton("Create GUI2");
button.addActionListener(new Listener());
add(panel);
add(button);
}
}
class GUI2 extends JFrame {
JPanel panel;
JLabel label;
public GUI2() {
super("GUI2");
setDefaultCloseOperation(EXIT_ON_CLOSE);
panel = new JPanel();
label = new JLabel("I'm alive!");
add(panel);
add(label);
}
}
class Listener implements ActionListener {
public void actionPerformed(ActionEvent e) {
GUI2.setVisible(true);
GUI1.dispose();
}
}

You have to pass instances of frame1 and frame2 to your ActionListener.
import java.awt.event.*;
public class Listener implements ActionListener {
private JFrame frame1, frame2;
public Listener(JFrame frame1, JFrame frame2) {
this.frame1 = frame1;
this.frame2 = frame2;
}
public void actionPerformed(ActionEvent e) {
frame2.setVisible(true);
frame1.dispose();
}
}
This means you have to pass an instance of frame2 to your GUI1 class.
import javax.swing.*;
public class GUI1 extends JFrame {
JPanel panel;
JButton button;
public GUI1(JFrame frame2) {
super("GUI1");
setDefaultCloseOperation(EXIT_ON_CLOSE);
panel = new JPanel();
button = new JButton("Create GUI2");
button.addActionListener(new Listener(this, frame2));
add(panel);
add(button);
}
}
This means you have to create the frames in the reverse order.
import javax.swing.*;
public class Test {
public static void main(String[] args) {
JFrame g2 = new GUI2();
g2.pack();
g2.setLocation(400,200);
g2.setVisible(false);
JFrame g1 = new GUI1(g2);
g1.pack();
g1.setLocation(200,200);
g1.setVisible(true);
}
}

Modal JDialog disappear when clicking on parent Window

I'm trying to learn Java (not a programmer by profession).
I'm currently working on a calendar app with Postgres backend.
My app consists of a JFrame with two JPanels. One of those Panels is a CalendarView(MonthView, WeekView, or DayView), and the other a ButtonPanel.
The ButtonPanel has a button to add a new Event to the Calendar. This button opens a JDialog for entering Event details (startDate, endDate, title, etc).
The owner of the dialog is the JFrame. The dialog is modular.
The issues I have is that when the dialog is open, if I click on the parent window, the dialog disappears. If I then move the cursor outside the main application window and back in, the dialog reappears. I was under the impression that this should not happen with a modal component.
All feedback appreciated. I made a slimmed down SSCCE:
import javax.swing.*;
import javax.swing.border.LineBorder;
import javax.swing.border.TitledBorder;
import java.awt.*;
public class Calendar extends JFrame {
public Calendar() {
super("Calendar");
initGUI();
}
public void initGUI() {
JPanel calendarView = new JPanel();
calendarView.setPreferredSize(new Dimension(400, 400));
calendarView.setBorder(BorderFactory.createTitledBorder(new LineBorder(Color.BLACK), "Calendar view", TitledBorder.CENTER, TitledBorder.CENTER));
JPanel buttonPanel = new ButtonPanel();
buttonPanel.setBorder(BorderFactory.createTitledBorder(new LineBorder(Color.RED), "Button panel", TitledBorder.CENTER, TitledBorder.CENTER));
buttonPanel.setPreferredSize(new Dimension(200, 400));
this.getContentPane().add(calendarView, BorderLayout.CENTER);
this.getContentPane().add(buttonPanel, BorderLayout.WEST);
this.pack();
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setLocationRelativeTo(null);
this.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
new Calendar();
}
});
}
}
mport java.awt.*;
import java.awt.event.ActionListener;
import javax.swing.*;
public class ButtonPanel extends JPanel {
public ButtonPanel() {
initGui();
}
private void initGui() {
GridBagLayout gbag = new GridBagLayout();
GridBagConstraints gbc = new GridBagConstraints();
this.setLayout(gbag);
JButton button = new JButton("Open dialog");
button.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent ae) {
new MyDialog((JFrame) ButtonPanel.this.getTopLevelAncestor());
}
});
gbag.setConstraints(button, gbc);
this.add(button);
}
}
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import javax.swing.*;
import javax.swing.border.LineBorder;
import javax.swing.border.TitledBorder;
import java.awt.*;
public class MyDialog extends JDialog {
public MyDialog(JFrame owner) {
super(owner, "My dialog", true);
initGUI(owner);
}
private void initGUI(JFrame owner){
JOptionPane optionPane = new JOptionPane(createPanel(), JOptionPane.PLAIN_MESSAGE, JOptionPane.DEFAULT_OPTION, null, createButtons(), createButtons()[0]);
this.add(optionPane, BorderLayout.CENTER);
this.pack();
this.setDefaultCloseOperation(JDialog.DISPOSE_ON_CLOSE);
this.setLocationRelativeTo(owner);
this.setVisible(true);
}
private JPanel createPanel() {
JPanel panel = new JPanel();
panel.setBorder(BorderFactory.createTitledBorder(new LineBorder(Color.BLACK), "My dialog", TitledBorder.CENTER, TitledBorder.CENTER));
return panel;
}
private JButton[] createButtons() {
JButton[] buttons = new JButton[1];
JButton button = new JButton("Exit");
button.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent event){
MyDialog.this.dispose();
}
});
buttons[0] = button;
return buttons;
}
}

How to swap JPanel's from an action in a JPanel

I am new(ish) to Java Swing but I have not been able to find an elegant solution to my issue so I thought I'd raise a question here.
I am trying to make my current JPanel change to another JPanel based on a button click event from within the current JPanel. In essence just hiding one panel and displaying the other. I feel this can be done within my MainFrame class however I'm not sure how to communicate this back to it. Nothing I am trying simply seems to do as desired, I'd appreciate any support. Thanks
App.java
public static void main(final String[] args) {
MainFrame mf = new MainFrame();
}
MainFrame.java
public class MainFrame extends JFrame {
public MainFrame(){
setTitle("Swing Application");
setSize(1200, 800);
setDefaultCloseOperation(DISPOSE_ON_CLOSE);
setVisible(true);
// First Page Frame switch
getContentPane().add(new FirstPage());
}
}
FirstPage.java
public class FirstPage extends JPanel {
public FirstPage() {
setVisible(true);
JButton clickBtn = new JButton("Click");
clickBtn.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent actionEvent) {
// Change to SecondPage JPanel here.
}
});
add(clickBtn);
}
}
SecondPage.java
public class SecondPage extends JPanel {
public SecondPage() {
setVisible(true);
add(new JLabel("Welcome to the Second Page"));
}
}
Any more information needed, please ask thanks :)

I think the best way is to use CardLayout. It is created for such cases. Check my example:
public class MainFrame extends JFrame {
private CardLayout cardLayout;
public MainFrame() {
super("frame");
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
cardLayout = new CardLayout();
getContentPane().setLayout(cardLayout);
getContentPane().add(new FirstPage(this::showPage), Pages.FIRST_PAGE);
getContentPane().add(new SecondPage(this::showPage), Pages.SECOND_PAGE);
setLocationByPlatform(true);
pack();
}
public void showPage(String pageName) {
cardLayout.show(getContentPane(), pageName);
}
public static interface PageContainer {
void showPage(String pageName);
}
public static interface Pages {
String FIRST_PAGE = "first_page";
String SECOND_PAGE = "second_page";
}
public static class FirstPage extends JPanel {
public FirstPage(PageContainer pageContainer) {
super(new FlowLayout());
JButton button = new JButton("next Page");
button.addActionListener(e -> pageContainer.showPage(Pages.SECOND_PAGE));
add(button);
}
}
public static class SecondPage extends JPanel {
public SecondPage(PageContainer pageContainer) {
super(new FlowLayout());
add(new JLabel("This is second page."));
JButton button = new JButton("Go to first page");
button.addActionListener(e -> pageContainer.showPage(Pages.FIRST_PAGE));
add(button);
}
}
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> new MainFrame().setVisible(true));
}
}

CardLayout is the right tool for the job.
You can simply create the ActionListener used to swap pages in JFrame class, and pass a reference of it to FirstPage:
import java.awt.CardLayout;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
public class MainFrame extends JFrame {
public MainFrame(){
setTitle("Swing Application");
setSize(1200, 800);
setDefaultCloseOperation(DISPOSE_ON_CLOSE);
setLocationByPlatform(true);
//Create card layout and set it to the content pane
CardLayout cLayout = new CardLayout();
setLayout(cLayout);
//create and add second page to the content pane
JPanel secondPage = new SecondPage();
add("SECOND",secondPage);
//create an action listener to swap pages
ActionListener listener = actionEvent ->{
cLayout.show(getContentPane(), "SECOND");
};
//use the action listener in FirstPage
JPanel firstPage = new FirstPage(listener);
add("FIRST", firstPage);
cLayout.show(getContentPane(), "FIRST");
setVisible(true);
}
public static void main(String[] args) {
new MainFrame();
}
}
class FirstPage extends JPanel {
public FirstPage(ActionListener listener) {
JButton clickBtn = new JButton("Click");
clickBtn.addActionListener(listener);
add(clickBtn);
}
}
class SecondPage extends JPanel {
public SecondPage() {
add(new JLabel("Welcome to the Second Page"));
}
}

Using card layout, cards not swapping?

I want to keep my Controller panel as type JPanel as I will be incorporating into a tab later, I want to swap between Main and NextPage using buttons on those specific screens, I don't want to have consistent buttons on the bottom for both screens that switch between cards(i.e I don't want to have add & back to be appearing on both screens), I am trying to get the add button in Main to go to NextPage and back button in NextPage to go to Main. This is what I have so far:
For Controller:
import java.awt.CardLayout;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class Controller extends JPanel {
private static Controller instance = new Controller();
JPanel cards;
Main mainPanel;
NextPage nextPage;
public Controller() {
setLayout(new BorderLayout());
setSize(810, 510);
cards = new JPanel(new CardLayout());
mainPanel = new Main();
nextPage = new NextPage();
cards.add(mainPanel, "Main");
cards.add(nextPage, "Next");
add(cards);
setVisible(true);
}
private static void createAndShowGUI() {
JFrame frame = new JFrame("MainPanel");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
Controller con = new Controller();
frame.getContentPane().add(con);
frame.setSize(800, 600);
frame.setVisible(true);
}
public static void main(String[] args) {
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});
}
public void changeCard(String card) {
CardLayout cl = (CardLayout) (cards.getLayout());
cl.show(cards, card);
}
public static Controller getInstance() {
return instance;
}
}
For main:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
import java.util.*;
public class Main extends JPanel implements ActionListener {
private JButton search, add, delete;
private JTextField textField;
public Main() {
search = new JButton("Search");
add = new JButton("Add");
delete = new JButton("Delete");
textField = new JTextField(20);
add.addActionListener(this);
delete.addActionListener(this);
setLayout(new BorderLayout());
JPanel top = new JPanel();
top.add(search);
add(top, BorderLayout.NORTH);
JPanel bottom = new JPanel();
bottom.add(add);
bottom.add(delete);
add(bottom, BorderLayout.SOUTH);
setVisible(true);
setSize(400, 500);
}
public void actionPerformed(ActionEvent e) {
if (e.getSource() == add) {
Controller.getInstance().changeCard("Next");
} else if (e.getSource() == delete) {
System.out.println("do something");
}
}
}
For NextPage:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
import java.util.*;
public class NextPage extends JPanel implements ActionListener {
private JButton back;
private JTextField textField;
public NextPage() {
back = new JButton("Back");
textField = new JTextField(20);
back.addActionListener(this);
setLayout(new BorderLayout());
add(back);
setVisible(true);
setSize(400, 500);
}
public void actionPerformed(ActionEvent e) {
if (e.getSource() == back) {
Controller.getInstance().changeCard("Next");
}
}
}

Check out Card Layout Actions.
It is an extension of CardLayout that provides you with Previous/Next buttons that you can easily add to a panel separate from the CardLayout.

How to send an ActionPerformed from an ActionListener to another ActionListener?

I've got a Frame (named here "MainApplication"), which mainly has a JPanel to show informations, depending on the context.
On startup, the MainApplication has an empty JPanel.
It then creates a "LoginRequest" class, which creates a simple login/password form, and send it back to the MainApplication, which displays it in its JPanel.
The "LoginRequest" class implements ActionListener, so when the user clicks on the "Login" button, it checks wheter or not the login/password is correct, and, if the user is granted, I want to unload that form, and display the main screen on the MainApplication Frame.
So, to do it, I came up with this :
public class LoginRequest implements ActionListener {
protected MainApplication owner_m = null;
public LoginRequest(MainApplication owner_p) {
owner_m = owner_p;
}
#Override
public void actionPerformed(ActionEvent event_p) {
// the user just clicked the "Login" button
if (event_p.getActionCommand().equals("RequestLogin")) {
// check if login/password are correct
if (getParameters().isUserGranted(login_l, password_l)) {
// send an ActionEvent to the "MainApplication", so as it will
// be notified to display the next screen
this.owner_m.actionPerformed(
new java.awt.event.ActionEvent(this, 0, "ShowSummary")
);
} else {
messageLabel_m.setForeground(Color.RED);
messageLabel_m.setText("Incorrect user or password");
}
}
}
}
Then, the "MainApplication" class (which extends JFrame) :
public class MainApplication extends JFrame implements ActionListener {
protected void load() {
// create the panel to display information
mainPanel_m = new JPanel();
// on startup, populate the panel with a login/password form
mainPanel_m.add(new LoginRequest(this).getLoginForm());
this.add(mainPanel_m);
}
#Override
public void actionPerformed(ActionEvent event_p) {
// show summary on request
if (event_p.getActionCommand().equals("ShowSummary")) {
// remove the previous information on the panel
// (which displayed the login form on this example)
mainPanel_m.removeAll();
// and populate the panel with other informations, from another class
mainPanel_m.add(...);
...
...
}
// and then refresh GUI
this.validate();
this.repaint();
this.pack();
}
}
When the ActionEvent is sent from the "LoginRequest" class to the "MainApplication" class, it executes the code, but at the end, nothing happens, as if the JFrame wasn't repainted.
Any ideas ?
Thanks,

The best way would be to use JDialog (main frame JFrame would be a parent component) for login form and CardLayout to switch between panels (so there is no need for removing, repainting and revalidating):
Your main form should look something like this:
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
public class MainFrame{
JFrame frame = new JFrame("Main frame");
JPanel welcomePanel = new JPanel();
JPanel workspacePanel = new JPanel();
JPanel cardPanel = new JPanel();
JButton btnLogin = new JButton("Login");
JLabel lblWelcome = new JLabel("Welcome to workspace");
CardLayout cl = new CardLayout();
LoginRequest lr = new LoginRequest(this);
public MainFrame() {
welcomePanel.add(btnLogin);
btnLogin.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
lr.setVisible(true);
}
});
workspacePanel.add(lblWelcome);
cardPanel.setLayout(cl);
cardPanel.add(welcomePanel, "1");
cardPanel.add(workspacePanel, "2");
cl.show(cardPanel,"1");
frame.getContentPane().add(cardPanel);
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.setPreferredSize(new Dimension(320,240));
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String [] args){
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
new MainFrame();
}
});
}
}
Your login form should look something like this:
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
public class LoginRequest extends JDialog{
/**You can add, JTextFields, JLabel, JPasswordField..**/
JPanel panel = new JPanel();
JButton btnLogin = new JButton("Login");
public LoginRequest(final MainFrame mf) {
setTitle("Login");
panel.add(btnLogin);
btnLogin.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
//Put some login logic here
mf.cl.show(mf.cardPanel,"2");
dispose();
}
});
add(panel, BorderLayout.CENTER);
setModalityType(ModalityType.APPLICATION_MODAL);
setDefaultCloseOperation(JDialog.DISPOSE_ON_CLOSE);
pack();
setLocationByPlatform(true);
}
}
EDIT:
Your way:
MainFrame class:
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
public class MainFrame{
JFrame frame = new JFrame("Main frame");
JPanel welcomePanel = new JPanel();
JPanel workspacePanel = new JPanel();
JPanel cardPanel = new JPanel();
JButton btnLogin = new JButton("Login");
JLabel lblWelcome = new JLabel("Welcome");
LoginRequest lr = new LoginRequest(this);
public MainFrame() {
welcomePanel.add(btnLogin);
btnLogin.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
lr.setVisible(true);
}
});
workspacePanel.add(lblWelcome);
frame.getContentPane().add(welcomePanel);
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.setPreferredSize(new Dimension(320,240));
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String [] args){
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
new MainFrame();
}
});
}
}
LoginRequest class:
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
public class LoginRequest extends JDialog{
/**You can add, JTextFields, JLabel, JPasswordField..**/
JPanel panel = new JPanel();
JButton btnLogin = new JButton("Login");
public LoginRequest(final MainFrame mf) {
setTitle("Login");
panel.add(btnLogin);
btnLogin.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
//Put some login logic here
mf.frame.getContentPane().removeAll();
mf.frame.add(mf.workspacePanel);
mf.frame.repaint();
mf.frame.revalidate();
dispose();
}
});
add(panel, BorderLayout.CENTER);
setModalityType(ModalityType.APPLICATION_MODAL);
setDefaultCloseOperation(JDialog.DISPOSE_ON_CLOSE);
pack();
setLocationByPlatform(true);
}
}