I have an applet that calls a JDialog that contains a JProgressBar component. I subclass the JDialog to expose a method to update the JProgressBar, something like:
public class ProgressDialog extends javax.swing.JDialog {
public void setProgress(double progress) {
jProgressBar1.setValue(jProgressBar1.getMinimum() + (int) (progress * jProgressBar1.getMaximum()));
}
...
}
I use this dialog in the following manner:
public void test() throws Exception {
progressDialog = new ProgressDialog(null, true);
try {
progressDialog.setLocationRelativeTo(null);
// show the dialog
EventQueue.invokeLater(new Runnable() {
public void run() {
progressDialog.setVisible(true);
}
});
// business logic code that calls progressDialog.setProgress along the way
doStuff();
} finally {
progressDialog.setVisible(false);
progressDialog.dispose();
}
}
It works fine on Windows/any browser. However, when invoking the above function on Firefox 2/3/3.5 on a Mac, the progressDialog is displayed indefinitely, i.e. it doesn't close.
I suspected that calling setVisible(true) inside the EventQueue was causing the problem, since it's a blocking call and might block the queue completely, so I tried changing it to:
// show the dialog
new Thread() {
public void run() {
progressDialog.setVisible(true);
}
}.start();
With this change, the progressDialog now closes correctly, but a new problem emerged - the contents of the dialog (which included the progressbar, an icon and a JLabel used to show a message string) were no longer shown inside the dialog. It was still a problem only on Mac Firefox.
Any ideas? I realize it's probably some AWT threading issue, but I've been at this for a couple of days and can't find a good solution. Wrapping the doStuff() business logic in a separate new Thread seems to work, but it's not easy to refactor the actual business logic code into a separate thread, so I'm hoping there's a simpler solution.
The envt is:
Mac OSX 10.5
Java 1.5
Firefox 2/3/3.5
Found out that the problem was that the applet function was executing inside the AWT dispatcher thread, therefore the thread blocks and no events are processed until the applet function finishes execution.
Solution was to move the processing logic into a separate thread spawned by the ProgressDialog object before calling setVisible(true). setVisible(true) would block the main thread but still allow the event dispatcher to continue processing, hence rendering the contents of the dialog until the spawned thread calls setVisible(false) to hide the dialog.
Related
So I am trying to do a chat type program using JavaFX for the GUI. I have it so a class that acts as a server will loop and keep adding client connections to it.
public void serverconnection()
{
// portnumber was saved from constructor
try (ServerSocket socket = new ServerSocket(this.portnumber))
{
// loop is a bool set to true
while (loop)
{
// this class extends Thread and has its own overwritten start method
new myclass(socket.accept()).start();
}
}
catch (IOException e)
{
System.exit(404);
}
}
so the problem is (I am assuming) was, this loop keeps looping until the program closes. but since I was calling this within the JavaFX's initialize method
public void initialize(URL url, ResourceBundle rb)
{
// constructor, nothing here is needed for this post
myclass z = new myclass(45234);
// problem here, since this has a loop, but
z.serverconnection();
// gui wont load till after this is done
// but serverconnection is only done after program ends
}
the problem with this is, apparently, the GUI will not load until AFTER initialize has finished, but it will not finish until program closes. After google searching, I could not find any fix for this. I need a way to call a method that will do all this, AFTER initialize method has finished. My client side class is similar to this, but the methods to connect on that are activated on events when clicking a login button. For this serverside one, I am trying to start without any interaction with the user. so is there a way to call a method or make this work AFTER initialize method has ran?
You might want to run this loop in a thread, so do something like
Thread t = new Thread(z::serverconnection)
t.start()
If you do this at the end of your initialization() method, it will run exactly then.
This will start a thread which runs forever; you might want to add a feature for interrupting the thread when the program is supposed to be terminated.
Remember that for changing anything in the GUI you need to sumbit a task via Platform.runLater(). This is because the GUI may only be modified from within that one thread. So in order to modify anything, you have to wrap that in a Runnable and submit it for execution.
You can do that in this way:
Platform.runLater(new Runnable() {
#Override
public void run() {
doWhateverNeedsToBeDone();
}
});
In Java 8, you can do anything of the following, depending on the extent of the work to be done:
Platform.runLater(() -> {
doWhateverNeedsToBeDone();
});
Platform.runLater(() -> doWhateverNeedsToBeDone());
Platform.runLater(this::doWhateverNeedsToBeDone);
The latter only works if doWhateverNeedsToBeDone() is a method of this.
I am executing several SQL queries in the function evoked by a button in java. I wish to show the status of the same, and I am using a jProgressBar for the same. But the problem is it will only update after the button has finished executing itself, making it pointless to show the progress. How can I display the actual progress of the executing button.
Make a thread dispatcher like this
public class ThreadDispatcher implements Runnable {
public ThreadDispatcher() {
}
public void run() {
//call the method related to query here
}
}
When button pressed call this class and let this class evoke your query related function.
It may be like this when you press the button.
Thread thread = new Thread(new ThreadDispatcher());
thread.start();
sleep(100);
catch the InterruptedException ex.
Link for Thread example
You need to do the computation on a background thread, not the main thread.
Take a look at the Java SwingWorker Tutorial.
I have written following code.I have not shown full source but psudo code.
class UI extends JFrame
{
//created UI with one Button
onButtonclick()
{
//did some operation before set icon to button
//say opened fileopen dialog and get file
button.setText("");
ImageIcon progressbar = new
ImageIcon(DatasetExporterUI.class.getResource("/progreassbar.gif"));
buttonExport.setIcon(progressbar);
// did some database operations
//again removed icon from button
button.setIcon(null);
button.setText("click");
}
}
When I click on button It opens file open dialog and and button text get set to empty.
But It doesn't set Icon to button.When all Database operation are done which are performed after Icon set to button that time Icon is appeared on button.
Why this behavior is?
How to set Icon to button and do some Database operations and again remove it?
Thank you. :)
The GUI system can only do one thing at a time, like most code (except for code that uses threads). Calling your listener is a thing. The GUI system cannot do anything else while your listener is running.
Your database operation needs to run on another thread (which you can create) and then update the GUI when it's done. Something like this:
void onButtonPressed() {
// The code to open the file dialog goes here
button.setText("");
ImageIcon progressbar = new
ImageIcon(DatasetExporterUI.class.getResource("/progreassbar.gif"));
buttonExport.setIcon(progressbar);
new Thread() {
#Override
public void run() {
// do some database operations here
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
//again remove icon from button
button.setIcon(null);
button.setText("click");
}
});
}
}.start();
}
Code in different threads runs at the same time. This is convenient but dangerous. Be extremely careful when accessing data from the new thread - if one thread changes a field and the other thread reads it, the results might not be what you expect. The simplest thing to do is to make sure the main thread doesn't change any variables used by the new thread while it's running.
When your database operations are finished, you can't set the button back to normal by just calling setText. Only the main thread is allowed to affect the GUI - what if the main thread was drawing the button on the screen at the same time the database operation thread was changing the text? The button might be drawn incorrectly. So you need to call EventQueue.invokeLater which tells the GUI system to run your code in the near future when it's not busy. The code inside new Runnable() {} is like the code in the button listener - no other GUI-related code will run while it does.
This should work:
Image progressbar= ImageIO.read(DatasetExporterUI.class.getResource("/progreassbar.gif"));
buttonExport.setIcon(new ImageIcon(progressbar));
I am using eclipse's jobs API to run big task as a job, once task is completed I am setting boolean variable to true and if that variable is true I am executing WizardDialog in UI thread. My current code looks like this:
Job longRunningJob = new Job("Long running job...") {
#Override
protected IStatus run(IProgressMonitor monitor) {
boolean shouldShowDialog = doLongRunningJob();
if(shouldShowDialog) {
Display.getDefault().asyncExec(new Runnable() {
#Override
public void run() {
//Will open wizard dialog here
WizardDialog wizardDialog = new WizardDialog(Display.getCurrent().getActiveShell(), new TestWizard());
wizardDialog.setBlockOnOpen(true);
wizardDialog.open();
}
});
}
}
}
longRunningJob.setUser(true);
longRunningJob.schedule();
My problem is run inside Display thread not executing in reliable way, means sometime it goes inside run method where as sometimes it doesn't, I tried putting breakpoint inside run method and testing it out but same happens.
My question is, is what I am doing is correct way? Is this expected behaviour? So how do I handle this scenario ie once shouldShowDialog is true how do I execute code inside Display thread?
Edit: One behaviour I observed while debugging is dialog gets displayed but suddenly it get closes, I think it's exiting the thread.
The problem with disappearing dialogs is most commonly caused by using currently active Shell as the parent for the dialog. E.g. if there is a ProgressDialog open when you create your dialog then that other dialog will be the parent of your dialog. And when the other dialog closes, so does yours.
Instead, use something like:
PlatformUI.getWorkbench().getActiveWorkbenchWindow().getShell();
I have a Java/Swing desktop application (Java 6u16 on Windows XP) which occasionally appears to the users to hang. I say appears to because in reality what is happening is that the application is showing a modal dialog but this dialog is not being rendered. If the user uses Alt-Tab to switch away from the application and then subsequently returns to it, the dialog gets rendered correctly. Additionally, if a remote user connects to the session via NetOp (a VNC/Remote Desktop workalike) this also causes the GUI to be redrawn correctly.
The app runs via JavaWebstart. Since I've heard of rendering issues being caused by DirectDraw, I added the following to the JNLP
<property name="sun.java2d.noddraw" value="true"/>
but the problem still occurs (If I have understood correctly, this will switch off DirectDraw and Direct3d completely: see http://download.oracle.com/javase/1.5.0/docs/guide/2d/flags.html#noddraw)
I'm out of ideas on this one, any suggestions would be greatly appreciated.
Thanks,
Phil
Edit...
I have an abstract dialog class which extends JDialog and which all other dialogs extend. It contains the following method:
public void showDialog() {
initKeyBindings();
Application.getApplication().deactivateScannerListener();
setVisible(true);
}
Whenever I want to display a dialog, I call showDialog(). The initKeyBindings method sets up an ActionMap while the second line is application specific (Application is a singleton, I'm disabling the JPOS scanner listener while the dialog is displaying).
There is a corresponding hideDialog() method as follows:
public void hideDialog() {
setVisible(false);
Application.getApplication().activateScannerListener();
dispose();
}
Thanks,
Phil
Edit...
Sorry about this, one more edit: all of the dialogs have a parent. The AbstractDialog class will default to the main application frame if no other parent is specified.
FYI
For anyone following this, I've added the following to my code:
if (SwingUtilities.isEventDispatchThread()) {
initialiseAndShowDialog();
} else {
SwingUtilities.invokeAndWait(new Runnable() {
#Override
public void run() {
initialiseAndShowDialog();
}
});
}
This ensures that the dialog is only opened from the EDT.
Which thread are you calling showDialog() from? Swing components should be accessed on the Event Dispatch Thread only.
You could try SwingUtilities.invokeAndWait()
and the Runnable argument passed to it should call showDialog().
Let us know if it fixed the problem.