Develop Reference

How do you close a JFrame window without closing another one?

I am new to Java Swing and I am trying to learn how to close one frame without closing the other one using button. For example I have a frame1/window that just have a button called login. Once I click on login button, another window appear frame2. On frame2 I just have a sample JLabel "Hello And Welcome", button called Logout. I want to be able to click on the Logout button on frame2 and frame2 window should close, but frame1 window show still be open. I have try setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE), but it only work if I click on the x icon on the top right of the frame2 window. Does anyone know of a way to close a frame when you click on a button?
public class Frame1 extends JFrame implements ActionListener{
private static JButton login = new JButton("Login");
private static JFrame f = new JFrame("Login");
Frame1(){
f.setSize(1000,750);
f.setLocation(750, 250);
login.setBounds(250, 350, 150, 30);
f.add(login);
f.setLayout(null);
f.setVisible(true);
login.addActionListener(this);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public void actionPerformed(ActionEvent e){
if (e.getSource() == login){
Frame2.frame2windown();
}
}
public static void main(String [] args){
Frame1 login1 = new Frame1();
}
}
public class Frame2 extends JFrame implements ActionListener{
private static JButton logout = new JButton("Logout");
private static JLabel jb1 = new JLabel ("Hello And Welcome");
private static JFrame f = new JFrame("Log Out");
Frame2(){
f.setSize(1000,750);
f.setLocation(750, 250);
jb1.setBounds(250, 150, 350, 30);
logout.setBounds(250, 350, 150, 30);
f.add(logout);
f.add(jb1);
f.setLayout(null);
f.setVisible(true);
logout.addActionListener(this);
f.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
}
public void actionPerformed(ActionEvent a){
if(a.getSource() == logout){
dispose();
WindowEvent closeWindow = new WindowEvent(this, JFrame.DISPOSE_ON_CLOSE);
Toolkit.getDefaultToolkit().getSystemEventQueue().postEvent(closeWindow);
}
}
public static void frame2windown(){
Frame2 f2 = new Frame2();
}
}

So, there are a whole bunch of concepts your need to try and learn.
It's generally recommended NOT to extend from top level containers (like JFrame). You're not adding any new functionality too them; they are complicated, compound components; you lock yourself into a single use case (what happens if you want to include the UI in another UI or use a dialog instead of frame?!)
Multiple frames aren't always a good idea and can be confusing to the user. Generally, with login workflows though, I might argue a login dialog is generally a better solution, but you need to understand the use cases to make those determinations.
Swing is a large, rich and diverse API, it has a LOT of inbuilt functionality, which you can use, to make your life easier (although it doesn't always seem this way)
Layout managers are an absolutely required feature and you really need to take the time to learn them, see Laying Out Components Within a Container for more details.
So, a really quick example of using a CardLayout and a basic "observer pattern", which decouples and separates responsibility.
import java.awt.CardLayout;
import java.awt.EventQueue;
import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.EventListener;
import java.util.Random;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.border.EmptyBorder;
public class Test {
public static void main(String[] args) {
new Test();
}
public Test() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
JFrame frame = new JFrame();
frame.add(new NavigationPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public static class NavigationPane extends JPanel {
protected enum NavigationTarget {
LOGIN, MAIN;
}
private LoginPane loginPane;
private MainPane mainPane;
private CardLayout cardLayout;
public NavigationPane() {
cardLayout = new CardLayout();
setLayout(cardLayout);
loginPane = new LoginPane();
loginPane.addLoginListener(new LoginPane.LoginListener() {
#Override
public void loginDidFail(LoginPane source) {
JOptionPane.showMessageDialog(NavigationPane.this, "You are not unauthroised", "Error", JOptionPane.ERROR_MESSAGE);
}
#Override
public void loginWasSuccessful(LoginPane source) {
navigateTo(NavigationTarget.MAIN);
}
});
mainPane = new MainPane();
add(loginPane, NavigationTarget.LOGIN.name());
add(mainPane, NavigationTarget.MAIN.name());
navigateTo(NavigationTarget.LOGIN);
}
protected void navigateTo(NavigationTarget target) {
cardLayout.show(this, target.name());
}
}
public static class LoginPane extends JPanel {
public static interface LoginListener extends EventListener {
public void loginDidFail(LoginPane source);
public void loginWasSuccessful(LoginPane source);
}
public LoginPane() {
setBorder(new EmptyBorder(10, 10, 10, 10));
setLayout(new GridBagLayout());
JButton btn = new JButton("Login");
btn.addActionListener(new ActionListener() {
private Random rnd = new Random();
#Override
public void actionPerformed(ActionEvent e) {
// Do some logic here
if (rnd.nextBoolean()) {
fireLoginWasSuccessful();
} else {
fireLoginDidFail();
}
}
});
add(btn);
}
public void addLoginListener(LoginListener listener) {
listenerList.add(LoginListener.class, listener);
}
public void removeLoginListener(LoginListener listener) {
listenerList.remove(LoginListener.class, listener);
}
protected void fireLoginDidFail() {
LoginListener[] listeners = listenerList.getListeners(LoginListener.class);
for (LoginListener listener : listeners) {
listener.loginDidFail(this);
}
}
protected void fireLoginWasSuccessful() {
LoginListener[] listeners = listenerList.getListeners(LoginListener.class);
for (LoginListener listener : listeners) {
listener.loginWasSuccessful(this);
}
}
}
public static class MainPane extends JPanel {
public MainPane() {
setLayout(new GridBagLayout());
setBorder(new EmptyBorder(10, 10, 10, 10));
add(new JLabel("Welcome"));
}
}
}
JDialog based login workflow
import java.awt.BorderLayout;
import java.awt.CardLayout;
import java.awt.Component;
import java.awt.EventQueue;
import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Random;
import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.border.EmptyBorder;
public class Test {
public static void main(String[] args) {
new Test();
}
public Test() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
NavigationPane navigationPane = new NavigationPane();
JFrame frame = new JFrame();
frame.add(navigationPane);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
if (LoginPane.showLoginDialog(navigationPane)) {
navigationPane.didLogin();
} else {
frame.dispose();
}
}
});
}
public static class NavigationPane extends JPanel {
protected enum NavigationTarget {
SPLASH, MAIN;
}
private SplashPane splashPane;
private MainPane mainPane;
private CardLayout cardLayout;
public NavigationPane() {
cardLayout = new CardLayout();
setLayout(cardLayout);
mainPane = new MainPane();
splashPane = new SplashPane();
add(splashPane, NavigationTarget.SPLASH.name());
add(mainPane, NavigationTarget.MAIN.name());
navigateTo(NavigationTarget.SPLASH);
}
protected void navigateTo(NavigationTarget target) {
cardLayout.show(this, target.name());
}
public void didLogin() {
navigateTo(NavigationTarget.MAIN);
}
}
public static class LoginPane extends JPanel {
private Random rnd = new Random();
private boolean isAuthorised = false;
public LoginPane() {
setBorder(new EmptyBorder(10, 10, 10, 10));
setLayout(new GridBagLayout());
add(new JLabel("User name and password fields go here"));
}
protected void authenticate() {
// Authenticate
isAuthorised = rnd.nextBoolean();
if (!isAuthorised) {
JOptionPane.showMessageDialog(this, "You are not authorised", "Error", JOptionPane.ERROR_MESSAGE);
}
}
// So this should return some kind of "session" or something so
// can identify the user, but for now, we'll just use
// a boolean
public boolean isAuthorised() {
return isAuthorised;
}
public static boolean showLoginDialog(Component parent) {
LoginPane loginPane = new LoginPane();
JPanel panel = new JPanel(new BorderLayout());
JPanel buttonPane = new JPanel(new GridBagLayout());
JButton okayButton = new JButton("Login");
JButton cancelButton = new JButton("Cancel");
buttonPane.add(okayButton);
buttonPane.add(cancelButton);
panel.add(loginPane);
panel.add(buttonPane, BorderLayout.SOUTH);
JDialog dialog = new JDialog(SwingUtilities.windowForComponent(parent));
dialog.add(panel);
okayButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
loginPane.authenticate();
if (loginPane.isAuthorised()) {
dialog.dispose();
}
}
});
cancelButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
dialog.dispose();
}
});
dialog.setModal(true);
dialog.pack();
dialog.setLocationRelativeTo(parent);
dialog.setVisible(true);
return loginPane.isAuthorised();
}
}
public static class SplashPane extends JPanel {
public SplashPane() {
setLayout(new GridBagLayout());
setBorder(new EmptyBorder(10, 10, 10, 10));
add(new JLabel("This is a splash panel, put some nice graphics here"));
}
}
public static class MainPane extends JPanel {
public MainPane() {
setLayout(new GridBagLayout());
setBorder(new EmptyBorder(10, 10, 10, 10));
add(new JLabel("Welcome"));
}
}
}

You duplicated the JFrame, created a JFrame field f inside the JFrame.
Do not use static components like the button.
public class Frame1 extends JFrame implements ActionListener {
private final JButton login = new JButton("Login");
Frame1() {
setTitle("Login");
setSize(1000, 750);
setLocation(750, 250);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLayout(null);
login.setBounds(250, 350, 150, 30);
add(login);
login.addActionListener(this);
setVisible(true);
}
public void actionPerformed(ActionEvent e) {
if (e.getSource() == login) {
Frame2.frame2windown();
}
}
public static void main(String[] args) {
EventQueue.invokeLater(() -> {
Frame1 login1 = new Frame1();
}
}
}
Use the swing/awt event queue (invokeLater) as on this thread window events are handled and dispatched further.
And Frame2:
public class Frame2 extends JFrame implements ActionListener {
private JButton logout = new JButton("Logout");
private JLabel jb1 = new JLabel("Hello And Welcome");
Frame2() {
setTitle("Logout");
setSize(1000, 750);
setLocation(750, 250);
setLayout(null);
setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
jb1.setBounds(250, 150, 350, 30);
logout.setBounds(250, 350, 150, 30);
add(logout);
add(jb1);
logout.addActionListener(this);
setVisible(true);
}
public void actionPerformed(ActionEvent a) {
if (a.getSource() == logout) {
setVisible(false); // <--- ALL
}
}
public static void frame2windown() {
Frame2 f2 = new Frame2();
}
}
JFrame.setVisible does it all. Especially setVisible(true) should maybe even done after the constructor is called, so it always is last.
Another remark, dive into layout managers fast. Absolute layouts (null) are a PITA.

Java,Swing - JPanel doesn't appear in JFrame as expected

I got a java class called PleaseWait and want to call it whenever a heavy task is in progress. When my program does a heavy task, in the first row in my actionListener I set a variable of this class setVisible(true) then set setVisible(true) at the end of the actionListener.
Somehow the JPanel in this class does not appear when I call it, it's just a window with title as set and white blank content. Here's my code:
public class PleaseWait extends JFrame{
public PleaseWait(){
Toolkit toolkit = Toolkit.getDefaultToolkit();
Dimension screenDimensions = toolkit.getScreenSize();
setSize(300,100); //set size based on screen size
setTitle("Please wait");
Container container = getContentPane();
setLocation(new Point(screenDimensions.width*1/4+200, screenDimensions.height*1/4+200)); //set location based on screen size
JPanel panel = new JPanel();
JLabel wait = new JLabel("Please wait");
Dimension buttonsSize = new Dimension(300,100);
panel.setPreferredSize(buttonsSize);
wait.setPreferredSize(buttonsSize);
panel.setLayout(new BorderLayout());
panel.add(wait, BorderLayout.CENTER);
container.add(panel);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setResizable(false); //unresizable
}

The key is not in the code you've posted, but in this line:
and want to call it whenever a heavy task is in progress
You're running a "heavy" task, and while you're running it, Swing is not painting this GUI, because you're likely running that task on the Swing event thread, and doing so freezes the thread, and your GUI.
Solution: use a background thread such as is obtainable through a SwingWorker, to run the "heavy" task.
Other side issues:
This appears to be a "dependent" or "sub" window off of the main application. If so, it should not be a JFrame since an application should only have one main application window, but rather it should be a JDialog.
You're using setPreferredSize(...) and hard-coding your component sizes, something fraught with problems.
e.g.,
import java.awt.*;
import java.awt.Dialog.ModalityType;
import java.awt.event.ActionEvent;
import java.awt.event.KeyEvent;
import javax.swing.*;
public class TestPleaseWait {
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> {
MainPanel mainPanel = new MainPanel();
JFrame frame = new JFrame("Application");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(mainPanel);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
});
}
}
#SuppressWarnings("serial")
class MainPanel extends JPanel {
private static final int PREF_W = 600;
private static final int PREF_H = 450;
public MainPanel() {
add(new JButton(new AbstractAction("Without Background Thread") {
{
putValue(MNEMONIC_KEY, KeyEvent.VK_O);
}
#Override
public void actionPerformed(ActionEvent e) {
final PleaseWait wait = new PleaseWait();
wait.setVisible(true);
try {
Thread.sleep(4000);
} catch (InterruptedException e1) {
}
wait.setVisible(false);
}
}));
add(new JButton(new AbstractAction("With Background Thread") {
private JDialog waitDialog = null;
private MyWaitPanel myWaitPanel = new MyWaitPanel();
{
putValue(MNEMONIC_KEY, KeyEvent.VK_W);
}
#Override
public void actionPerformed(ActionEvent e) {
if (waitDialog == null) {
Component component = MainPanel.this;
Window win = SwingUtilities.getWindowAncestor(component);
waitDialog = new JDialog(win, "Please Wait", ModalityType.APPLICATION_MODAL);
waitDialog.add(myWaitPanel);
waitDialog.pack();
waitDialog.setLocationRelativeTo(win);
}
new Thread(() -> {
try {
Thread.sleep(4000);
} catch (InterruptedException e1) {
}
SwingUtilities.invokeLater(() -> {
waitDialog.setVisible(false);
});
}).start();
waitDialog.setVisible(true);
}
}));
}
#Override
public Dimension getPreferredSize() {
if (isPreferredSizeSet()) {
return super.getPreferredSize();
}
return new Dimension(PREF_W, PREF_H);
}
}
#SuppressWarnings("serial")
class MyWaitPanel extends JPanel {
private JProgressBar progressBar = new JProgressBar();
public MyWaitPanel() {
progressBar.setIndeterminate(true);
JLabel waitLabel = new JLabel("Please Wait", SwingConstants.CENTER);
waitLabel.setFont(waitLabel.getFont().deriveFont(Font.BOLD, 40));
int ebGap = 10;
setBorder(BorderFactory.createEmptyBorder(ebGap, ebGap, ebGap, ebGap));
setLayout(new BorderLayout(ebGap, ebGap));
add(waitLabel, BorderLayout.PAGE_START);
add(progressBar);
}
}
#SuppressWarnings("serial")
class PleaseWait extends JFrame {
public PleaseWait() {
Toolkit toolkit = Toolkit.getDefaultToolkit();
Dimension screenDimensions = toolkit.getScreenSize();
setSize(300, 100); // set size based on screen size
setTitle("Please wait");
Container container = getContentPane();
setLocation(new Point(screenDimensions.width * 1 / 4 + 200,
screenDimensions.height * 1 / 4 + 200));
JPanel panel = new JPanel();
JLabel wait = new JLabel("Please wait");
Dimension buttonsSize = new Dimension(300, 100);
panel.setPreferredSize(buttonsSize);
wait.setPreferredSize(buttonsSize);
panel.setLayout(new BorderLayout());
panel.add(wait, BorderLayout.CENTER);
container.add(panel);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setResizable(false); // unresizable
}
}

Swing JLabel missing characters

So I have come across a peculiar problem.
My interface is just a single label, and a JSlider.
My code(stripped):
import javax.swing.*;
import java.awt.*;
public class Broken {
JLabel value = new JLabel();
JSlider slider = new JSlider(0, 255, 0);
public Broken() {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
JPanel panel = new JPanel();
value.setText("Some Value");
panel.add(value);
JFrame frame = new JFrame("Frame Name");
frame.setLayout(new GridLayout(2, 1));
frame.add(panel);
frame.add(slider);
frame.pack();
frame.setVisible(true);
}
});
}
public static void main(String[] args) {
new Broken();
}
}
What happens is the label doesn't show up. If I resize the screen from the right to the smallest possible, suddenly the text appears, and it will stay there if I resize back to what it was. I have no idea what's happening, this truly seems like a bug to me.
Before and after resizing screenshots:

Despite your efforts, you're not on the EventDispatchThread when you're creating your JLabel (or JSlider, for that matter). To test, I subclassed JLabel just see if the code was on the EDT when it's constructor is called:
import java.awt.*;
import javax.swing.*;
public class Broken {
JLabel value = new XLabel(); // called before constructor, so not on EDT
JSlider slider = new JSlider(0, 255, 0); // same here
public Broken() {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
JPanel panel = new JPanel();
value.setText("Some Value");
panel.add(value);
JFrame frame = new JFrame("Frame Name");
frame.setLayout(new GridLayout(2, 1));
frame.add(panel);
frame.add(slider);
frame.pack();
frame.setVisible(true);
}
});
}
public static void main(String[] args) {
new Broken();
}
class XLabel extends JLabel {
public XLabel() {
super();
System.out.println("EDT? " + SwingUtilities.isEventDispatchThread());
}
}
}
To fix, place the invokeLater call in main, so as to wrap the entire construction of your class onto the EDT:
import java.awt.*;
import javax.swing.*;
public class Broken2 {
JLabel value = new JLabel();
JSlider slider = new JSlider(0, 255, 0);
public Broken2() {
JPanel panel = new JPanel();
value.setText("Some Value");
panel.add(value);
JFrame frame = new JFrame("Frame Name2");
frame.setLayout(new GridLayout(2, 1));
frame.add(panel);
frame.add(slider);
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args) {
// Generally the proper way. Create Whole app on EDT
SwingUtilities.invokeLater(new Runnable() {
public void run() {
new Broken2();
}
});
}
}

JFrame Trigger Events on Close

I know the title isn't very explanatory, I was unsure of how to phrase the question. What I have is a GUI that I want to trigger an event when the window in closed (including when you force quit the window/application). Thank you in advance for any help!!! Here's my code:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.io.IOException;
import java.io.Serializable;
public class NotAVirus extends JFrame {
private JTextField statusField = new JTextField(20);
private JButton yesButton = new JButton("Open");
private JButton noButton = new JButton("Close");
private static NotAVirus app = new ImLost();
public static void main() {
app.setVisible(true);
app.setLocationRelativeTo(null);
}
/**
* Create the GUI and show it. For thread safety,
* this method should be invoked from the
* event-dispatching thread.
*/
public ImLost() {
super("ImLost");
statusField.setText("There's No Escape");
statusField.setHorizontalAlignment(JLabel.CENTER);
statusField.setEditable(false);
add(statusField, BorderLayout.CENTER);
JPanel p = new JPanel();
p.setLayout(new GridLayout(1, 2));
p.add(yesButton);
p.add(noButton);
add(p, BorderLayout.SOUTH);
yesButton.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e) {
app.setVisible(false);
for(int i = 0; i <= 10000; i ++)
{
JFrame frame = new JFrame("ImLost");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JLabel emptyLabel = new JLabel("");
emptyLabel.setPreferredSize(new Dimension(160, 1));
frame.getContentPane().add(emptyLabel, BorderLayout.CENTER);
//Display the window.
frame.setLocation((int)(Math.random() * ((1280) + 1)),(int)(Math.random() * ((800) + 1)));
frame.pack();
frame.setVisible(true);
}
}
});
noButton.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e) {
app.setVisible(false);
for(int i = 0; i <= 10000; i ++)
{
JFrame frame = new JFrame("ImLost");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JLabel emptyLabel = new JLabel("");
emptyLabel.setPreferredSize(new Dimension(160, 1));
frame.getContentPane().add(emptyLabel, BorderLayout.CENTER);
//Display the window.
frame.setLocation((int)(Math.random() * ((1280) + 1)),(int)(Math.random() * ((800) + 1)));
frame.pack();
frame.setVisible(true);
}
}
});
p.setPreferredSize(new Dimension(200, 35));
pack();
}

You can add a WindowListener to the JFrame:
frame.addWindowListener(new WindowListener() {
#Override
public void windowOpened(WindowEvent e) {
}
#Override
public void windowClosing(WindowEvent e) {
//window is being closed
}
#Override
public void windowClosed(WindowEvent e) {
//window is closed
}
#Override
public void windowIconified(WindowEvent e) {
}
#Override
public void windowDeiconified(WindowEvent e) {
}
#Override
public void windowActivated(WindowEvent e) {
}
#Override
public void windowDeactivated(WindowEvent e) {
}
});
I want to trigger an event when the window in closed (including when you force quit the window/application)
If you mean "when someone kills the process" i think it wouldn't be possible, as the process gets killed and so stops its execution immediately. If you mean "when the application freezes and the user forces it to close" I think it wouldn't be possible too, usually if you force the quit of an application, it means that it's frozen and it's not responding anymore, so executing other code of it wouldn't be possible.

Java : Swing : Hide frame after button pressed

I have a button in a java frame that when pressed it reads a value from a text field and uses that string as a port name attempting to connect to a serial device.
If this connection is successful the method returns true if not it returns false. If it returns true I want the frame to disappear. A series of other frames specifed in other classes will then appear with options to control the serial device.
My problem is: the button is connected to an action listener, when pressed this method is invoked. If I try to use the frame.setVisible(true); method java throws a abstract button error because I'm effectively telling it to disappear the frame containing the button before the button press method has exited. Removing the frame.setVisible(true); allow the program to run correctly however I am left with a lingering connection frame that is no longer any use.
How to I get the frame to disappear upon pressing a the button?
package newimplementation1;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
/**
*
* #author Zac
*/
public class ConnectionFrame extends JPanel implements ActionListener {
private JTextField textField;
private JFrame frame;
private JButton connectButton;
private final static String newline = "\n";
public ConnectionFrame(){
super(new GridBagLayout());
textField = new JTextField(14);
textField.addActionListener(this);
textField.setText("/dev/ttyUSB0");
connectButton = new JButton("Connect");
//Add Components to this panel.
GridBagConstraints c = new GridBagConstraints();
c.gridwidth = GridBagConstraints.REMAINDER;
c.fill = GridBagConstraints.HORIZONTAL;
add(textField, c);
c.fill = GridBagConstraints.BOTH;
c.weightx = 1.0;
c.weighty = 1.0;
add(connectButton, c);
connectButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e)
{
boolean success = Main.mySerialTest.initialize(textField.getText());
if (success == false) {System.out.println("Could not connect"); return;}
frame.setVisible(false); // THIS DOES NOT WORK!!
JTextInputArea myInputArea = new JTextInputArea();
myInputArea.createAndShowGUI();
System.out.println("Connected");
}
});
}
public void actionPerformed(ActionEvent evt) {
// Unimplemented required for JPanel
}
public void createAndShowGUI() {
//Create and set up the window.
frame = new JFrame("Serial Port Query");
frame.setDefaultCloseOperation(JFrame.HIDE_ON_CLOSE);
//Add contents to the window.
frame.add(new ConnectionFrame());
frame.setLocation(300, 0);
//Display the window.
frame.pack();
frame.setVisible(true);
frame.addComponentListener(new ComponentAdapter() {
#Override
public void componentHidden(ComponentEvent e) {
System.out.println("Exiting Gracefully");
Main.mySerialTest.close();
((JFrame)(e.getComponent())).dispose();
System.exit(0);
}
});
}
}

Running your snippet (after removing/tweaking around the custom classes), throws an NPE. Reason is that the frame you'r accessing is null. And that's because it's never set. Better not rely on any field, let the button find its toplevel ancestor and hide that, like in
public void actionPerformed(final ActionEvent e) {
boolean success = true;
if (success == false) {
System.out.println("Could not connect");
return;
}
Window frame = SwingUtilities.windowForComponent((Component) e
.getSource());
frame.setVisible(false); //no problem :-)
}

Your problem is with this line:
frame.add(new ConnectionFrame());
You're creating a new ConnectionFrame object, and so the frame that your button tries to close on is not the same as the one being displayed, and this is the source of your problem.
If you change it to,
//!! frame.add(new ConnectionFrame());
frame.add(this);
so that the two JFrames are one and the same, things may work more smoothly.
But having said that, your whole design smells bad and I'd rethink it in a more OOP and less static fashion. Also, use dialogs where dialogs are needed, not frames, and rather than dialogs consider swapping views (JPanels) via CardLayout as a better option still.
Myself, I'd create a "dumb" GUI for this, one that creates a JPanel (here in my example it extends a JPanel for simplicity, but I'd avoid extending if not necessary), and I'd let whoever is calling this code decide what to do with the information via some control. For e.g.,
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
#SuppressWarnings("serial")
public class ConnectionPanel extends JPanel {
private JTextField textField;
private JButton connectButton;
private ConnectionPanelControl control;
public ConnectionPanel(final ConnectionPanelControl control) {
super(new GridBagLayout());
this.control = control;
ActionListener listener = new ActionListener() {
public void actionPerformed(ActionEvent e) {
if (control != null) {
control.connectButtonAction();
}
}
};
textField = new JTextField(14);
textField.addActionListener(listener);
textField.setText("/dev/ttyUSB0");
connectButton = new JButton("Connect");
GridBagConstraints c = new GridBagConstraints();
c.gridwidth = GridBagConstraints.REMAINDER;
c.fill = GridBagConstraints.HORIZONTAL;
add(textField, c);
c.fill = GridBagConstraints.BOTH;
c.weightx = 1.0;
c.weighty = 1.0;
add(connectButton, c);
connectButton.addActionListener(listener);
}
public String getFieldText() {
return textField.getText();
}
}
Again, something outside of the simple GUI would make decisions on what to do with the text that the textfield contains and what to do with the GUI that is displaying this JPanel:
public interface ConnectionPanelControl {
void connectButtonAction();
}
Also, you will likely do any connecting in a background thread so as to not freeze your GUI, probably a SwingWorker. Perhaps something like this:
import java.awt.event.ActionEvent;
import java.util.concurrent.ExecutionException;
import javax.swing.*;
#SuppressWarnings("serial")
public class MyMain extends JPanel {
public MyMain() {
add(new JButton(new ConnectionAction("Connect", this)));
}
private static void createAndShowGui() {
JFrame frame = new JFrame("My Main");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(new MyMain());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
#SuppressWarnings("serial")
class ConnectionAction extends AbstractAction {
private MyMain myMain;
private ConnectionPanel cPanel = null;
private JDialog dialog = null;
public ConnectionAction(String title, MyMain myMain) {
super(title);
this.myMain = myMain;
}
#Override
public void actionPerformed(ActionEvent e) {
if (dialog == null) {
dialog = new JDialog(SwingUtilities.getWindowAncestor(myMain));
dialog.setTitle("Connect");
dialog.setModal(true);
cPanel = new ConnectionPanel(new ConnectionPanelControl() {
#Override
public void connectButtonAction() {
final String connectStr = cPanel.getFieldText();
new MySwingWorker(connectStr).execute();
}
});
dialog.getContentPane().add(cPanel);
dialog.pack();
dialog.setLocationRelativeTo(null);
}
dialog.setVisible(true);
}
private class MySwingWorker extends SwingWorker<Boolean, Void> {
private String connectStr = "";
public MySwingWorker(String connectStr) {
this.connectStr = connectStr;
}
#Override
protected Boolean doInBackground() throws Exception {
// TODO: make connection and then return a result
// right now making true if any text in the field
if (!connectStr.isEmpty()) {
return true;
}
return false;
}
#Override
protected void done() {
try {
boolean result = get();
if (result) {
System.out.println("connection successful");
dialog.dispose();
} else {
System.out.println("connection not successful");
}
} catch (InterruptedException e) {
e.printStackTrace();
} catch (ExecutionException e) {
e.printStackTrace();
}
}
}
}

Your code would be much more readable if you named JFrame instances xxxFrame, and JPanel instances xxxPanel. Naming JPanel instances xxxFrame makes things very confusing.
It would also help if you pasted the stack trace of the exception.
I suspect the problem comes from the fact that frame is null. This is due to the fact that the frame field is only initialized in the createAndShowGUI method, but this method doesn't display the current connection panel, but a new one, which thus have a null frame field:
ConnectionFrame firstPanel = new ConnectionFrame();
// The firstPanel's frame field is null
firstPanel.createAndShowGUI();
// the firstPanel's frame field is now not null, but
// the above call opens a JFrame containing another, new ConnectionFrame,
// which has a null frame field
The code of createAndShowGUI should contain
frame.add(this);
rather than
frame.add(new ConnectionFrame());

for Swing GUI is better create only once JFrame and another Top-Level Containers would be JDialog or JWindow(un-decorated by default),
simple example here
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class SuperConstructor extends JFrame {
private static final long serialVersionUID = 1L;
public SuperConstructor() {
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setPreferredSize(new Dimension(300, 300));
setTitle("Super constructor");
Container cp = getContentPane();
JButton b = new JButton("Show dialog");
b.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent evt) {
FirstDialog firstDialog = new FirstDialog(SuperConstructor.this);
}
});
cp.add(b, BorderLayout.SOUTH);
JButton bClose = new JButton("Close");
bClose.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent evt) {
System.exit(0);
}
});
add(bClose, BorderLayout.NORTH);
pack();
setVisible(true);
}
public static void main(String args[]) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
SuperConstructor superConstructor = new SuperConstructor();
}
});
}
private class FirstDialog extends JDialog {
private static final long serialVersionUID = 1L;
FirstDialog(final Frame parent) {
super(parent, "FirstDialog");
setPreferredSize(new Dimension(200, 200));
setLocationRelativeTo(parent);
setDefaultCloseOperation(JDialog.DISPOSE_ON_CLOSE);
setModalityType(Dialog.ModalityType.DOCUMENT_MODAL);
JButton bNext = new JButton("Show next dialog");
bNext.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent evt) {
SecondDialog secondDialog = new SecondDialog(parent, false);
}
});
add(bNext, BorderLayout.NORTH);
JButton bClose = new JButton("Close");
bClose.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent evt) {
setVisible(false);
}
});
add(bClose, BorderLayout.SOUTH);
pack();
setVisible(true);
}
}
private int i;
private class SecondDialog extends JDialog {
private static final long serialVersionUID = 1L;
SecondDialog(final Frame parent, boolean modal) {
//super(parent); // Makes this dialog unfocusable as long as FirstDialog is visible
setPreferredSize(new Dimension(200, 200));
setLocation(300, 50);
setModal(modal);
setDefaultCloseOperation(JDialog.DISPOSE_ON_CLOSE);
setTitle("SecondDialog " + (i++));
JButton bClose = new JButton("Close");
bClose.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent evt) {
setVisible(false);
}
});
add(bClose, BorderLayout.SOUTH);
pack();
setVisible(true);
}
}
}
better would be re-use Top-Level Containers, as create lots of Top-Level Containers on Runtime (possible memory lack)