I'm writing a GUI that is able to perform some JUnit Tests and to handle this I have used a SwingWorker.
When I start the program the GUI comes up and I click through some selections and the SwingWorker initiates and does it's part and finally outputs either a console output or file output. Then I would click through the GUI again and start another test. At this point when the program finishes it would generate the final output twice, e.g. the console output would be followed directly by an identical console output.
I am assuming this is due to the SwingWorker not terminating and "dying".
Also I am creating the SwingWorker when I click a "start" button in the GUI. Is this a bad idea and what would the proper way to do it be instead?
EDIT Added code sample
public class TestMainFrame {
private static JFrame frame;
private static JTextArea textArea;
public TestMainFrame(){
createAndShowGUI();
}
private void createAndShowGUI() {
frame = new JFrame("Test");
frame.setLayout(new BorderLayout());
JButton btn = new JButton("Test Me");
btn.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
if(btn.getText().equals("Test Me")){
testMe();
}
}
});
textArea = new JTextArea("This is a test pane! \n");
textArea.setEditable(false);
JScrollPane scroller = new JScrollPane(textArea);
frame.add(scroller, BorderLayout.CENTER);
frame.add(btn, BorderLayout.PAGE_END);
frame.setSize(new Dimension(300, 400));
frame.setVisible(true);
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
private static void testMe(){
writeToTextArea("Button Pressed");
writeToTextArea("Starting tests");
SwingWorker<Result, Void> worker = new SwingWorker<Result, Void>() {
#Override
public Result doInBackground() {
writeToTextArea("Inside the doInBackground method of SwingWorker");
return null;
}
#Override
public void done() {
writeToTextArea("The SwingWorker has finished");
}
};
worker.execute();
}
private static void writeToTextArea(String text){
textArea.append(text + "\n");
}
(Not an answer)
This is how I ran your code:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class TestMainFrame {
private static JFrame frame;
private static JTextArea textArea;
public TestMainFrame() {
createAndShowGUI();
}
private void createAndShowGUI() {
frame = new JFrame("Test");
frame.setLayout(new BorderLayout());
final JButton btn = new JButton("Test Me");
btn.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
if (btn.getText().equals("Test Me")) {
testMe();
}
}
});
textArea = new JTextArea("This is a test pane! \n");
textArea.setEditable(false);
JScrollPane scroller = new JScrollPane(textArea);
frame.add(scroller, BorderLayout.CENTER);
frame.add(btn, BorderLayout.PAGE_END);
frame.setSize(new Dimension(300, 400));
frame.setVisible(true);
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
private static void testMe() {
writeToTextArea("Button Pressed");
writeToTextArea("Starting tests");
SwingWorker<Void, Void> worker = new SwingWorker<Void, Void>() {
#Override
public Void doInBackground() {
writeToTextArea("Inside the doInBackground method of SwingWorker");
return null;
}
#Override
public void done() {
writeToTextArea("The SwingWorker has finished");
}
};
worker.execute();
}
// *** note change ***
private static void writeToTextArea(final String text) {
if (SwingUtilities.isEventDispatchThread()) {
textArea.append(text + "\n");
} else {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
textArea.append(text + "\n");
}
});
}
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
TestMainFrame testMainFrame = new TestMainFrame();
testMainFrame.createAndShowGUI();
}
});
}
}
Related
I am trying to do when clicked button from form1 open form2. Its sounds very simple but i coudnt find any way to do this.I am using java intellij.
When i use netbeans and swing i was doing this with :
"Form2 form2=new Form2();
form2.setVisible(true);
dispose(); "
Form1(Main):
public class Main {
private JButton b_show;
private JButton b_Add;
private JPanel jp_main;
public Main() {
b_show.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent actionEvent) {
}
});
}
public static void main(String[]args){
JFrame frame=new JFrame();
frame.setContentPane(new Main().jp_main);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(300,300);
frame.setVisible(true);
}
}
form2(Show):
public class Show {
private JButton b_back;
public JPanel jpanelmain;
public Show() {
Show show=new Show();
geriButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent actionEvent) {
}
});
}
public static void main(String[]args){
JFrame frame=new JFrame();
frame.setContentPane(new Show().jpanelmain);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(300,300);
frame.setVisible(true);
}
}
is any one can help me ?
when click b_show open form2(Show).
Here is an mcve demonstrating it
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class Main {
private final JButton b_show;
private final JPanel jp_main;
public Main() {
jp_main = new JPanel();
b_show = new JButton("Show");
b_show.addActionListener(actionEvent -> {
new Show();
});
jp_main.add(b_show);
}
public static void main(String[]args){
JFrame frame=new JFrame();
frame.setContentPane(new Main().jp_main);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(300,300);
frame.setVisible(true);
}
}
class Show {
private JButton b_back;
public JPanel jpanelmain;
public Show() {
createAndShowGui();
}
void createAndShowGui(){
JFrame frame=new JFrame();
frame.setLocationRelativeTo(null);
jpanelmain = new JPanel();
b_back = new JButton("Back");
jpanelmain.add(b_back);
frame.setContentPane(jpanelmain);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(300,300);
frame.setVisible(true);
}
}
However, please read The Use of Multiple JFrames: Good or Bad Practice?
The best way to do this would be using JDialogs. When actionPerformed() at 'Form1' is called, you would instantiate a new JDialog and set him visible. Here is an example:
public class Show extends JDialog {
private JButton b_back;
public JPanel jpanelmain;
public Show(Frame owner, boolean modal) {
super(owner, modal);
}
//method that creates the GUI
}
b_show.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent actionEvent) {
Show show = new Show(JOptionPane.getFrameForComponent(this), true);
show.setVisible(true);
}
});
Finally, when you want to close the dialog, implement an actionPerformed() in it, and call the dispose() method
when I use updateComponentTreeUI for a non-empty JTextField, the position of the cursor is moved from the end of the text to the front, as seen in the given example. Can anybody think of a reason, a fix, or has experienced this? Since I have many textfields in many different classes, a global solution without adding a Listener to every textfield would be appreciated. Here is a simple example:
import java.awt.*;
import java.awt.Dialog.*;
import java.awt.event.*;
import java.lang.reflect.*;
import javax.swing.*;
public class DialogTest {
final JFrame frame = new JFrame("DialogTest");
JDialog dlg;
public DialogTest() {
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(new JButton(action1), BorderLayout.NORTH);
frame.add(new JButton(action2), BorderLayout.CENTER);
frame.pack();
frame.setLocation(200, 200);
frame.setVisible(true);
}
public static void main(String[] args) {
try {
SwingUtilities.invokeAndWait(new Runnable() {
#Override
public void run() {
new DialogTest();
}
});
} catch (InvocationTargetException | InterruptedException e1) {
}
}
private void setStuff() {
dlg = new JDialog(frame, "Dialog", ModalityType.DOCUMENT_MODAL);
dlg.getContentPane().setLayout(new BorderLayout());
dlg.getContentPane().add(new JTextField("test 123", 20), BorderLayout.NORTH);
dlg.getContentPane().add(new JTextField("Bla bla bla bla bla", 20), BorderLayout.CENTER);
dlg.getContentPane().add(new JButton(new AbstractAction("Close") {
#Override
public void actionPerformed(ActionEvent e) {
dlg.setVisible(false);
}
}), BorderLayout.SOUTH);
dlg.setLocation(250, 250);
}
final Action action1 = new AbstractAction("Dialog") {
#Override
public void actionPerformed(ActionEvent e) {
setStuff();
dlg.pack();
dlg.setVisible(true);
}
};
final Action action2 = new AbstractAction("UpdateComponentTree") {
#Override
public void actionPerformed(ActionEvent e) {
setStuff();
SwingUtilities.updateComponentTreeUI(dlg);
dlg.pack();
dlg.setVisible(true);
}
};
}
I am using a self made toolbar to navigate through my application and the toolbar is present on all pages. Each time a new page is displayed I am closing the current frame and opening a new one, using the following code:
java.awt.Window win[] = java.awt.Window.getWindows();
for(int i=0;i<win.length;i++){
win[i].dispose();
}
I am doing it this way as the ActionListeners are declared in the toolbar class, whilst the frames for each page are declared at runtime and are not static.
This all works fine except for one particular case-the "cancel" button, where the first time the frame is accessed it will close once. The second time it will close and re open 2 times, the third 3 and so on. I have tracked this using the "counter" in the code.
I have minimised the code to recreate the same behaviour, as below:
Toolbar Class
public class Toolbar {
static JButton buttonCancel = new JButton("Cancel");
static int counter;
public static JPanel Toolbar(String panelname){
FlowLayout layout = new FlowLayout();
JPanel Toolbar = new JPanel(new BorderLayout());
Toolbar.setLayout(layout);
GridLayout GLayout = new GridLayout(2,1);
GLayout.setVgap(0);
JPanel container2 = new JPanel();
if(panelname.matches("Customers")){
container2.setLayout(GLayout);
JButton buttonAddCust = new JButton("Add Cust");
container2.add(buttonAddCust, BorderLayout.PAGE_START);
buttonAddCust.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
java.awt.Window win[] = java.awt.Window.getWindows();
for(int i=0;i<win.length;i++){
win[i].dispose();
}
Customers.AddCustomersGui();
}
});
}
JPanel container21 = new JPanel();
if(panelname.matches("Add Customers")){
container21.setLayout(GLayout);
container21.add(buttonCancel, BorderLayout.PAGE_START);
buttonCancel.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
counter ++;
java.awt.Window win[] = java.awt.Window.getWindows();
for(int i=0;i<win.length;i++){
win[i].dispose();
}
System.out.println("Coutner " + counter);
Customers.CustomersGui();
}
});
}
Toolbar.add(container2);
Toolbar.add(container21);
return Toolbar;
}
}
GUI class
public class Customers extends Toolbar{
public static void CustomersGui(){
final JFrame frame = new JFrame("Customers");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel customers = new JPanel();
customers.add(Toolbar.Toolbar(frame.getTitle()));
frame.setContentPane(customers);
frame.setSize(1200,500);
frame.setVisible(true);
}
public static void AddCustomersGui(){
final JFrame frame1 = new JFrame("Add Customers");
frame1.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel Addcustomers = new JPanel();
Addcustomers.add(Toolbar.Toolbar(frame1.getTitle()));
frame1.setContentPane(Addcustomers);
frame1.setSize(1200,500);
frame1.setVisible(true);
}
}
main class
public static void main(String[] args) {
Customers.CustomersGui();
}
You are adding a new ActionListener to the buttonCancel, with each iteration of your code and this is the reason for your program's behavior.
Also, as per my comment, you state,
Each time a new page is displayed I am closing the current frame and opening a new one.
A better design is probably not to swap windows which can be annoying, but rather to swap JPanel views using a CardLayout. Please read The Use of Multiple JFrames, Good/Bad Practice?.
For example, add this line of code to your program:
if (panelname.matches("Add Customers")) {
container21.setLayout(GLayout);
container21.add(buttonCancel, BorderLayout.PAGE_START);
buttonCancel.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
counter++;
java.awt.Window win[] = java.awt.Window.getWindows();
for (int i = 0; i < win.length; i++) {
win[i].dispose();
}
System.out.println("Coutner " + counter);
Customers.CustomersGui();
}
});
// ***** add this here **********
System.out.println("buttonCancel ActionListener count: "
+ buttonCancel.getListeners(ActionListener.class).length);
}
and you'll see that the ActionListeners get added multiple times to this button.
An example of swapping views:
import java.awt.*;
import java.awt.event.ActionEvent;
import javax.swing.*;
#SuppressWarnings("serial")
public class SwapPanels extends JPanel {
public static final String CUSTOMER = "customer";
public static final String ADD_CUSTOMER = "Add Customer";
protected static final int PREF_W = 800;
protected static final int PREF_H = 600;
public static final String CANCEL = "Cancel";
private CardLayout cardLayout = new CardLayout();
public SwapPanels() {
setLayout(cardLayout);
add(createCustomerPanel(CUSTOMER), CUSTOMER);
add(createAddCustomerPanel(ADD_CUSTOMER), ADD_CUSTOMER);
}
public void showCard(String key) {
cardLayout.show(this, key);
}
public JPanel createAddCustomerPanel(String name) {
JPanel addCustPanel = new JPanel() {
#Override
public Dimension getPreferredSize() {
if (isPreferredSizeSet()) {
return super.getPreferredSize();
}
return new Dimension(PREF_W, PREF_H);
}
};
addCustPanel.setName(name);
addCustPanel.setBorder(BorderFactory.createTitledBorder(name));
addCustPanel.add(new JButton(new AbstractAction(CANCEL) {
{
int mnemonic = (int)getValue(NAME).toString().charAt(0);
putValue(MNEMONIC_KEY, mnemonic);
}
#Override
public void actionPerformed(ActionEvent e) {
if (CANCEL.equals(e.getActionCommand())) {
SwapPanels.this.showCard(CUSTOMER);
}
}
}));
return addCustPanel;
}
private JPanel createCustomerPanel(String name) {
JPanel custPanel = new JPanel() {
#Override
public Dimension getPreferredSize() {
if (isPreferredSizeSet()) {
return super.getPreferredSize();
}
return new Dimension(PREF_W, PREF_H);
}
};
custPanel.setName(name);
custPanel.setBorder(BorderFactory.createTitledBorder(name));
custPanel.add(new JButton(new AbstractAction(ADD_CUSTOMER) {
{
int mnemonic = (int)getValue(NAME).toString().charAt(0);
putValue(MNEMONIC_KEY, mnemonic);
}
#Override
public void actionPerformed(ActionEvent e) {
if (ADD_CUSTOMER.equals(e.getActionCommand())) {
SwapPanels.this.showCard(ADD_CUSTOMER);
}
}
}));
return custPanel;
}
private static void createAndShowGui() {
JFrame frame = new JFrame("SwapPanels");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(new SwapPanels());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
i wanna to call youtubeviewer from a window by actionlistener
public class YouTubeViewer {
public YouTubeViewer(){
NativeInterface.open();
SwingUtilities.invokeLater(new Runnable() {
public void run() {
JFrame frame = new JFrame("YouTube Viewer");
frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
frame.getContentPane().add(getBrowserPanel(), BorderLayout.CENTER);
frame.setSize(800, 600);
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
});
NativeInterface.runEventPump();
Runtime.getRuntime().addShutdownHook(new Thread(new Runnable() {
#Override
public void run() {
NativeInterface.close();
}
}));
}
public JPanel getBrowserPanel() {
JPanel webBrowserPanel = new JPanel(new BorderLayout());
JWebBrowser webBrowser = new JWebBrowser();
webBrowserPanel.add(webBrowser, BorderLayout.CENTER);
webBrowser.setBarsVisible(false);
webBrowser.navigate("www.youtube.com/embed/sKeCX98U29M");
return webBrowserPanel;
}
}
jframe example(for testing)
public class trailerPlayer extends JPanel implements ActionListener
{
private JButton press;
public trailerPlayer ()
{
setLayout(new BorderLayout());
press = new JButton("press");
press.addActionListener(this);
add(press);
}
public void actionPerformed(ActionEvent actionEvent)
{
YouTubeViewer a = new YouTubeViewer();
}
public static void main(String args[ ])
{
trailerPlayer p = new trailerPlayer();
JFrame test = new JFrame();
test.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
test.add(p);
test.setSize(500,500);
test.setVisible(true);
}
}
YouTubeViewer include class of DJ Native Swing api library.
if i call directly by main function,it will work.but if i call from actionlistener it will stop responding at the time i press it~ i guess it is the problem of running issue~ how to solve ? any idea? thanks
any idea??
Your code blocks the EDT (NativeInterface.runEventPump();). So you should do it in a different thread.
public void actionPerformed(ActionEvent actionEvent)
{
Thread t = new Thread(new Runnable() {
public void run() {
YouTubeViewer a = new YouTubeViewer();
}
});
t.start();
}
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)