Develop Reference

How To use MouseClicked event to prevent mouseExited event?

I've got a simple java swing code where a text field changes when the button is hovered over and clicked, but when i use a variable to deactivate the mouseExited event, it does not work and continues to change the text field. I think its to do with the variable only being available to the mouseClicked event? How would i fix this. Thanks
my imports are java.awt and javax.swing
public static void main(String[] args) {
boolean check = true;
JFrame f =new JFrame("ActionListener Example");
JTextField tf = new JTextField("You should press button 1");
tf.setBounds(100,100, 150,20);
JButton b=new JButton("Click Here");
b.setBounds(50,100,60,30);
//2nd step
b.addMouseListener(new MouseListener() {
#Override
public void mouseClicked(MouseEvent e) {
tf.setText("you did it");
boolean check = false;
}
#Override
public void mousePressed(MouseEvent e) {
// TODO Auto-generated method stub
}
#Override
public void mouseReleased(MouseEvent e) {
// TODO Auto-generated method stub
}
#Override
public void mouseEntered(MouseEvent e) {
tf.setText("DO IT!");
}
#Override
public void mouseExited(MouseEvent e) {
if (check) {
tf.setText("You should press the button");
}
}});
f.setLayout(new FlowLayout());
f.setSize(400,400);
f.add(b);
f.add(tf);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setVisible(true);

I think its to do with the variable only being available to the mouseClicked event? How would i fix this.
Then don't define a second "check" variable in the mouseClicked method.
//boolean check = false;
check = false;
Edit:
Local variable check defined in an enclosing scope must be final or effectively final
Start be rewriting your entire class to give it a better structure.
Read the section from the Swing tutorial on How to Use Buttons.... Download the ButtonDemo code and modify it.
The demo code will show you how to structure your code so that
all the code is NOT contained in the main() method:
you use layout managers
you create the GUI on the Event Dispatch Thread (EDT)
your class can use "instance" variables, instead of a local variable. You "check" variable will be an instance variable.

Handling drag-and-drop with a moving list

I'm working with drag-and-drop. The user has to drag something from a list to somewhere else. However, the list will move when receiving a ListSelectionEvent, so when the user changes selection, he may unexpectedly perform a drag-and-drop.
My code:
import java.awt.*;
import javax.swing.*;
class Main {
public static void createGUI() {
JFrame f = new JFrame();
JList<String> list = new JList<>(new String[] { "Text A", "Text B" });
list.setFont(list.getFont().deriveFont(24f));
list.setDragEnabled(true);
// list.setTransferHandler(new TransferHandler() { /* ... */ });
list.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
list.addListSelectionListener(e -> f.setLocation(f.getX(),
f.getY() + f.getHeight()));
list.setSelectedIndex(0);
f.add(list, BorderLayout.CENTER);
f.pack();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setLocationByPlatform(true);
f.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(Main::createGUI);
}
}
To reproduce, launch this application, put it above some application that accepts a drop (e.g. Eclipse, Notepad++) and toggle the selection several times.
I'm using Windows 7 and JDK 1.8.0_5.
I tried but I couldn't find a work-around. How can I fix this issue?
[Not really related] This is my real application: (including the green cross icon)

Okay I think I understand your problem: You want to have DnD enabled, just not when the user is changing their selection. You should try this (in Java 7, I'm not too comfortable with lambda expressions yet, so I'm still not using Java 8. It'll work on Java 8 though):
class Main {
private static boolean listChanging = false;
public static void createGUI() {
final JFrame f = new JFrame();
JList<String> list = new JList<String>(new String[] { "Text A", "Text B" });
list.setFont(list.getFont().deriveFont(24f));
list.setDragEnabled(true);
list.setTransferHandler(new TransferHandler() {
private static final long serialVersionUID = 1L;
#Override
public int getSourceActions(JComponent c) {
if (listChanging) {
listChanging = false;
return NONE;
} else {
return COPY;
}
}
#Override
#SuppressWarnings("unchecked")
public Transferable createTransferable(JComponent c) {
return new StringSelection(((JList<String>) c).getSelectedValue());
}
});
list.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
list.addListSelectionListener(new ListSelectionListener() {
#Override
public void valueChanged(ListSelectionEvent e) {
f.setLocation(f.getX(), f.getY() + f.getHeight());
listChanging = true;
}
});
list.setSelectedIndex(0);
f.add(list, BorderLayout.CENTER);
f.pack();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setLocationByPlatform(true);
f.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
Main.createGUI();
}
});
}
}
What this code does is that when the user when the user changes selection it set a variable listChanging to true. The when the user drags (by accident or on purpose), it checks if listChanging is true, which means that this was probably an unexpected drag. If the list was not changing, then it allows COPY drags.
Basically, if the drag was during a list change, it disables DnD. If the list did not change, and the user purposefully dragged it enables DnD.
Hope this meets all your needs :)

Still It's not clear what you want to do with your application..
Drag and Drop performs with mouse/key events or you may trigger it through another events.
Here as I can see, it could be in this way that either you can select some of the components from List and perform DnD to transfer that component to another Container.
Please elaborate your question and ask specifically what exactly you want to perform with your sample application.

Java Swing, restore from system tray not working in Linux

I am creating an application in Java and I would like that when you minimize to an icon, the application will have to "hide" in the system tray.
The code I use is this: (the significant part of the code)
myFrame = new JFrame();
myFrame.addWindowListener(new WindowAdapter() {
#Override
public void windowIconified(WindowEvent e) {
PutTray();
}
#Override
public void windowDeiconified(WindowEvent e) {
System.out.println("Deiconified");
}
});
This is a "PutTray" function:
private void PutTray()
{
try
{
tray.add(trayIcon); // Initialized elsewhere
myFrame.setVisible(false);
} catch (AWTException e) {
System.err.println(e);
}
}
To restore (via option in the pop-up menu when you press the icon minimized):
MenuItem show = new MenuItem("Show");
show.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
myFrame.setVisible(true);
myFrame.setState(JFrame.NORMAL);
tray.remove(trayIcon);
}
});
The code works perfectly on Windows 8, but it does not work on Linux (Kali Linux and even Ubuntu).
Why Windows yes and Linux no?
EDIT:
On Linux, after you press the command to show the application, it appears for a very small moment, and then minimizes again. Basically is triggered the event "windowDeiconified" and immediately after the event "windowIconified" without taking the time to do something else and then the application is shown in the system tray.

As Dan Getz suggests, I also thought the order of setVisible and setState should be inverted since the javadoc for setState says:
If the frame is not visible on the
* screen, the events may or may not be
* generated.
but this didn't help.
The one thing that did help though was replacing setVisible(false) with dispose(). They are similar in that you can use setVisible(true) to reopen a disposed window. You can read more about it here: JDialog setVisible(false) vs dispose()
I'll try to find an explanation and come back with it :)
SSCCE to simulate OP problem:
public class Test {
private JFrame myFrame;
public Test() {
myFrame = new JFrame();
myFrame.setVisible(true);
myFrame.setSize(300, 300);
myFrame.addWindowListener(new WindowAdapter() {
#Override
public void windowIconified(WindowEvent e) {
PutTray();
}
});
}
private void PutTray() {
myFrame.setVisible(false); //replace with dispose(); and it's ok
Timer t = new Timer(1000, new ActionListener() {
#Override
public void actionPerformed(ActionEvent actionEvent) {
myFrame.setVisible(true);
}
});
t.setRepeats(false);
t.start();
}
public static void main(String[] args) {
new Test();
}
}

I think you are getting it wrong!
Maybe you are confused about deiconified and visibility
windowIconified()
will be called when we click minimize button
and
windowDeiconified()
is called when we restore it from taskbar and not system tray!
In order to restore from system tray you need to use this
trayIcon.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
window.setVisible(true);
}
});
Basically i don't think the difference between dispose() & setVisible() will bother you in this specific problem
Still, my recommendation is to use setVisible() here

How do I close a JDialog and have the Window Event Listeners be notified?

Is there a way to close a JDialog through code such that the Window event listeners will still be notified? I've tried just setting visible to false and disposing, but neither seem to do it.

Closing a window (with dispose()) and hiding it (with setVisible(false)) are different operations, and produce different events -- and closing it from the operating system is yet another different operation that produces yet a different event.
All three will produce windowDeactivated to tell you the window's lost focus, but dispose() will then produce windowClosed, while closing from the OS will first produce windowClosing. If you want to handle both of these the same way, you can set the window to be disposed when closed:
window.setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);
In general, setVisible(false) implies that you might want to use the window again, so it doesn't post any window events (apart from windowDeactivated). If you want to detect the hiding of a window, you need to use a ComponentListener;
window.addComponentListener(new ComponentAdapter() {
#Override
public void componentHidden(ComponentEvent e) {
System.out.println("componentHidden()");
}
})
Note though that this will pretty much only work for explicit setVisible() calls. If you need to detect hiding more generally, you can use a HierarchyListener, but it's probably more trouble than it's worth.
window.addHierarchyListener(new HierarchyListener() {
#Override
public void hierarchyChanged(HierarchyEvent e) {
System.out.println("valid: " + window.isValid());
System.out.println("showing: " + window.isShowing());
}
});
Note that when you dispose a window you'll get a couple of HierarchyEvents, first for hiding and then for invalidation, but when you hide it with setVisible() it's still valid, so you won't get the invalidation.

I don't seem to have your problem. When I use the code below windowDeactivated() is called for either setVisible( false ) or dispose() and windowClosed() is also called for dispose().
ClosingDialog.java:
public class ClosingDialog extends JDialog {
public ClosingDialog(Frame owner, String title, boolean modal) {
super(owner, title, modal);
JPanel contentPanel = (JPanel) this.getContentPane();
JButton setVisButton = new JButton("setVisible( false )");
setVisButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
ClosingDialog.this.setVisible(false);
}
});
JButton disposeButton = new JButton("dispose()");
disposeButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
ClosingDialog.this.dispose();
}
});
contentPanel.setLayout(new FlowLayout());
contentPanel.add(setVisButton);
contentPanel.add(disposeButton);
this.addWindowListener(new WindowListener() {
public void windowActivated(WindowEvent e) {
System.out.println("windowActivated");
}
public void windowClosed(WindowEvent e) {
System.out.println("windowClosed");
}
public void windowClosing(WindowEvent e) {
System.out.println("windowClosing");
}
public void windowDeactivated(WindowEvent e) {
System.out.println("windowDeactivated");
}
public void windowDeiconified(WindowEvent e) {
System.out.println("windowDeiconified");
}
public void windowIconified(WindowEvent e) {
System.out.println("windowIconified");
}
public void windowOpened(WindowEvent e) {
System.out.println("windowOpened");
}
});
this.setSize(300, 300);
}
}

Dispatch a windowClosing event to the Window. Check out the ExitAction example from the Closing an Application entry.

Untested suggestion:
Have you tried getWindowListeners() and then iterating around to fire windowClosed() to each of the WindowListeners?
EDIT: the above suggestion is wrong. Keeping it for posterity.
I'm afraid calling dialog.dispose() works fine for me in my simple example.

I wanted to fire a windowClosing event from the code (just as if the user clicked the X), because I have an extra close button in the JDialog and want the same WindowListener (that I implemented using a WindowAdapter) to be run when the X is clicked and when the button is clicked. Running dispose() only fires windowClosed, not windowClosing, and I want a message to appear before the window is closed, for confirmation. I also didn't manage to fire windowClosing via JDialog's method processWindowEvent since it is protected.
Here is how I got it working though:
WindowAdapter adapter = (WindowAdapter)jdialog.getWindowListeners()[0];
adapter.windowClosing(new WindowEvent((Window)jdialog, WindowEvent.WINDOW_CLOSING));
Hope that helps someone.

Why wont my JFrame hide?

I'm in the process of creating a GUI in Netbeans 6.1 for my senior design project but i've run into an annoying snag. Temporary Windows like my login PopUp and others wont disappear when i tell it. I've been researching how to solve this for about 2 months on an off. I've even mad a separate thread for my Pop Up but it still wont work....the only way it will disappear if i literally dont mess with any of the other GUI components....my sample code should help describe my anger...dont mind the shadow code, it was for testing purposes, which obviously didnt help.
//This method is called once a user presses the "first" login button on the main GUI
public synchronized void loginPopUpThread() {
doHelloWorld = new Thread(){
#Override
public synchronized void run()
{
try
{
loginPopUpFrame.pack();
loginPopUpFrame.setVisible(true);
System.out.println("waitin");
doHelloWorld.wait();
System.out.println("Not Sleepin..");
loginPopUpFrame.pack();
loginPopUpFrame.setVisible(false);
}
catch (InterruptedException e)
{
}
}
};
doHelloWorld.start();
//This is called when the "second" loginB is pressed and the password is correct...
public synchronized void notifyPopUp() {
synchronized(doHelloWorld) {
doHelloWorld.notifyAll();
System.out.println("Notified");
}
}
I've also tried Swing Utilities but maybe i implemented it wrong as it's my first time using them. It essentially does the same thing as the code above except the window freezes when it gets to wait, which the above code doesnt do:
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public synchronized void run() {
try
{
loginPopUpFrame.pack();
loginPopUpFrame.setVisible(true);
System.out.println("waitin");
wait();
System.out.println("Not Sleepin.");
loginPopUpFrame.pack();
loginPopUpFrame.setVisible(false);
}
catch (InterruptedException e)
{
}
}
});
PLEASE HELP ME!!!

Rules of thumb:
Don't manipulate GUI components in arbitrary threads; always arrange to manipulate them in the event thread
Never wait or sleep inside the event thread (so, never inside code sent to invokeLater())
So the answer to how you solve this problem is "some other way"...
Standing back from the problem a bit, what is it you're actually trying to do? If you just want a login dialog to wait for the user to enter user name and password, is there a reason not to just use a modal JDialog (after all, that's what it's there for...).
If you really do want some arbitrary thread to wait for a signal to close the window/manipulate the GUI, then you need to do the waiting in the other thread, and then make that thread call SwingUtilities.invokeLater() with the actual GUI manipulation code.
P.S. There are actually some GUI manipulation methods that it is safe to call from other threads, e.g. calls that are "just setting a label" are often safe. But which calls are safe isn't terribly well-defined, so it's best just to avoid the issue in practice.

The Swing components should only be manipulated by the swing event dispatch thread.
class SwingUtilites has methods to submit tasks to the dispatch thread.

It is difficult to diagnose your problem. I'm not sure what you're trying to do with the wait methods, but I recommend leaving wait/notify alone.
This code has two frames - when you create a second frame, the first is hidden until you close it.
public class SwapFrames {
private JFrame frame;
private JFrame createMainFrame() {
JButton openOtherFrameButton = new JButton(
"Show other frame");
frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
Container contentPane = frame.getContentPane();
contentPane.setLayout(new FlowLayout());
contentPane.add(openOtherFrameButton);
frame.pack();
openOtherFrameButton
.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
onClickOpenOtherFrame();
}
});
return frame;
}
private void onClickOpenOtherFrame() {
frame.setVisible(false);
JFrame otherFrame = new JFrame();
otherFrame
.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
otherFrame.setContentPane(new JLabel(
"Close this to make other frame reappear."));
otherFrame.pack();
otherFrame.setVisible(true);
otherFrame.addWindowListener(new WindowAdapter() {
#Override
public void windowClosed(WindowEvent e) {
frame.setVisible(true);
}
});
}
public static void main(String[] args) {
JFrame frame = new SwapFrames().createMainFrame();
frame.setVisible(true);
}
}
Because I don't see any evidence of them in your code, I'm going to suggest you read up on using event listeners rather than trying to "wait" for code to finish.
It isn't entirely clear what you're trying to achieve, but you might be better off with a modal dialog:
public class DialogDemo {
public JFrame createApplicationFrame() {
JButton openDialogButton = new JButton("Open Dialog");
final JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
Container container = frame.getContentPane();
container.setLayout(new FlowLayout());
container.add(openDialogButton);
frame.pack();
openDialogButton
.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
onOpenDialog(frame);
}
});
return frame;
}
private void onOpenDialog(JFrame frame) {
JDialog dialog = createDialog(frame);
dialog.setVisible(true);
}
private JDialog createDialog(JFrame parent) {
JButton closeDialogButton = new JButton("Close");
boolean modal = true;
final JDialog dialog = new JDialog(parent, modal);
dialog
.setDefaultCloseOperation(JDialog.DISPOSE_ON_CLOSE);
Container container = dialog.getContentPane();
container.add(closeDialogButton);
dialog.pack();
dialog.setLocationRelativeTo(parent);
closeDialogButton
.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
dialog.setVisible(false);
}
});
return dialog;
}
public static void main(String[] args) {
new DialogDemo().createApplicationFrame().setVisible(
true);
}
}

How about doing simply:
//This method is called once a user presses the "first" login button on the main GUI
public void loginPopUpThread() {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
loginPopUpFrame.pack();
loginPopUpFrame.setVisible(true);
}
};
}
//This is called when the "second" loginB is pressed and the password is correct...
public void notifyPopUp() {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
loginPopUpFrame.setVisible(false);
}
};
}

What you really want to be using is a modal JDialog.
Note, bits of this are left out. It's your homework/project.
public void actionPerformed(ActionEvent e)
{
// User clicked the login button
SwingUtilities.invokeLater(new Runnable()
{
public void run()
{
LoginDialog ld = new LoginDialog();
// Will block
ld.setVisible(true);
}
});
}
public class LoginDialog extends JDialog
{
public LoginDialog()
{
super((Frame)null, "Login Dialog", true);
// create buttons/labels/components, add listeners, etc
}
public void actionPerformed(ActionEvent e)
{
// user probably clicked login
// valid their info
if(validUser)
{
// This will release the modality of the JDialog and free up the rest of the app
setVisible(false);
dispose();
}
else
{
// bad user ! scold them angrily, a frowny face will do
}
}
}