So I have my IWorkbenchWiondow object, window.
I add this listener to it:
window.addPageListener(new IPageListener()
{
#Override
public void pageOpened(IWorkbenchPage page)
{
// method stub
}
/**
* Whenever the user tries to close the workbench window, this method gets called.
*/
#Override
public void pageClosed(IWorkbenchPage page)
{
if (MessageDialog.openQuestion(page.getWorkbenchWindow().getShell(), "Question", "Do you really want to close the application?"))
{
// YES, then no problem, close
return;
}
else
{
// NO
System.out.println("Now what?");
}
}
#Override
public void pageActivated(IWorkbenchPage page)
{
// method stub
}
});
How can I stop the window from closing if the user says No?
Or how can I achieve the same end result?
As #david said, the IWorkbenchListener has a preShutDown event that allows to veto the shutdown of the entire workbench by returning false.
The workbench is shut down when the last workbench window is closed or through actions such as File > Exit.
If you would like to prevent a single IWorkbenchWindow from being closed, you need to add a close listener to the shell that represents the workbench window.
For example:
Shell shell = window.getShell();
shell.addListener( SWT.Close, new Listener() {
public void handleEvent( Event event ) {
MessageBox messageBox = new MessageBox( parentShell, SWT.APPLICATION_MODAL | SWT.YES | SWT.NO );
messageBox.setText( "Confirmation" );
messageBox.setMessage( "Close the window?" );
event.doit = messageBox.open() == SWT.YES;
}
} );
Setting the doit flag to false will prevent the shell from being closed/disposed.
Caveat: I've only given this technique a minimal test and it appears to work as expected.
From the IWorkBenchWindow get an IWorkbench object.
Add an IWorkbenchListener to the workbench object.
The listener has a preShutdown method that should allow you to veto the close.
Related
I'm having a problem with my Java code.
I need to execute my doSomething() method, which includes code that manage also global variables. The problem is that the method is invoked twice (both mouseEvent and focusEvent of my JTable are fired at the same time).
How can I execute the doSomething() method only once at a time, in a sort of mutual exclusion ?
Thanks.
addMouseListener (new MouseAdapter() {
#Override
public void mouseClicked(MouseEvent e) {
doSomething();
}
});
addFocusListener(new FocusAdapter() {
#Override
public void focusLost(FocusEvent e){
doSomething();
}
});
JTable cells contains String with length 1 or 2.
I need to apply a setValue method (or delete the String), in the exact moment the user stops the cell editing or he writes a 2 character String.
With those listeners I know the exact time to do the setValue or to inform the user that the first character he wrote doesn't exist. So in that way I wanted to block the user's action.
In other words, I need to control the user input in order to do a setValue or delete it. FocusLost tells me when the user clicks outside the JTable Component.
MouseClicked tells me when the user clicks in the JTable Component.
When mouseClicked is invoked and the JOptionPane appears, the cell automatically lose the focus, and so also the focusLost is invoked.
public void doSomething () {
// inEdit and tableCellEdited are the global variables
if ( inEdit && tableCellEdited != null ) {
String temp = "" + tableCellEdited.getDay();
String s = tableCellEdited.getValRenderer().trim();
if (s.length() > 2) s = s.substring(4);
if ( !s.trim().isEmpty() ) {
JOptionPane.showMessageDialog(getParent(),
"Code doesn't exist" , "Error: Code doesn't exist",JOptionPane.WARNING_MESSAGE);
tableCellEdited.setRendererValue(getUltimaGG(), false);
}
else {
tableCellEdited.setRendererValue(s, false);
setValueAt(tableCellEdited, getRowFromMat(tableCellEdited.getMat()), Integer.parseInt(temp.substring(6, 8)) );
}
clearProgrammazioneDueCaratteri();
}
}
repaint();
}
What is the proper way to dispose of SWT Shells? I have created some Dialogs with success following the template given in the Dialog API docs. The SWT API for Dialog says:
The basic template for a user-defined dialog typically looks something
like this:
public class MyDialog extends Dialog {
Object result;
public MyDialog (Shell parent, int style) {
super (parent, style);
}
public MyDialog (Shell parent) {
this (parent, 0); // your default style bits go here (not the Shell's style bits)
}
public Object open () {
Shell parent = getParent();
Shell shell = new Shell(parent, SWT.DIALOG_TRIM | SWT.APPLICATION_MODAL);
shell.setText(getText());
// Your code goes here (widget creation, set result, etc).
shell.open();
Display display = parent.getDisplay();
while (!shell.isDisposed()) {
if (!display.readAndDispatch()) display.sleep();
}
return result;
}
}
The Dialogs I have created do not have their own taskbar icon on Windows, as I would expect for a Dialog. I now want to create some Shells, which if I understand correctly will receive their own taskbar entry on Windows?
In contrast to the directions given in the above API docs, I have also seen an article which seems to suggest that having a while loop as shown in the API docs is the wrong way to do it. The article instead suggests disposing the Shell by using the close event listener.
What is the correct way to dispose of SWT Shells (and while were on the topic, Dialogs as well)?
Hopefully I can help explain what's going on here.
Dialog is basically just a convenient class to subclass, because Shell itself is not supposed to be subclassed. You can create shells without using Dialog at all, if you want to. In this case, your MyDialog class is a class that others can use to open the same kind of dialog repeatedly.
This piece of code drives the SWT event loop as long as the shell is open (clicking the close button on the shell disposes the shell by default):
while (!shell.isDisposed()) {
if (!display.readAndDispatch()) display.sleep();
}
You have to call Display.readAndDispatch periodically to keep your SWT application from "locking up". Basically it causes all of the incoming events from the operating system (keyboard and mouse events, repaint events, etc.) to be correctly processed by your application. readAndDispatch basically takes an event from the application's event queue and invokes the correct listeners. In an Eclipse RCP application, the workbench is normally responsible for "pumping" the event loop and you don't have to mess with it. Here's a little more info about the event loop.
The purpose of "manually" pumping the event loop in this context is to prevent MyDialog.open from returning while the shell is not disposed, but still keep the application from "hanging". If your MyDialog.open method tried to wait for the shell to be disposed, but it didn't pump the event loop, your application would "lock up" because without the event loop running, there's no way for the shell to ever be notified that it should be disposed!
You can create shells without using this pattern. Here's an example of a very simple SWT application that opens a ton of shells all at once and keeps running as long as at least one of them is still open (I've omitted the package declaration and imports):
public class Shells {
private static int numDisposals = 0;
public static void main(String[] args) {
Display d = Display.getDefault();
for (int i = 0; i < 5; i++) {
Shell s = new Shell(d);
s.open();
s.addDisposeListener(new DisposeListener() {
#Override
public void widgetDisposed(DisposeEvent arg0) {
numDisposals++;
}
});
}
while (numDisposals < 5) {
while (!d.readAndDispatch()) {
d.sleep();
}
}
}
}
Note that I add a DisposeListener to each shell so I can take some action when the shell is closed. You can also use IShellListener to listen more directly for the close event and even actually prevent it (which you might want to do if the shell contains unsaved work, for example). Here's an annoying modification to the first program that starts 5 shells and randomly prevents you from closing them:
public class Shells {
private static Random r = new Random();
private static int numDisposals = 0;
public static void main(String[] args) {
Display d = Display.getDefault();
for (int i = 0; i < 5; i++) {
Shell s = new Shell(d);
s.open();
s.addShellListener(new ShellAdapter() {
#Override
public void shellClosed(ShellEvent e) {
boolean close = r.nextBoolean();
if (close) {
System.out.println("Alright, shell closing.");
} else {
System.out.println("Try again.");
}
e.doit = close;
}
});
s.addDisposeListener(new DisposeListener() {
#Override
public void widgetDisposed(DisposeEvent arg0) {
numDisposals++;
}
});
}
while (numDisposals < 5) {
while (!d.readAndDispatch()) {
d.sleep();
}
}
}
}
Hopefully this has helped make things more clear!
Edited to add: I'm not totally sure why you aren't getting a windows taskbar item for your shell, but I suspect it has something to do with the style flags you're passing into the shell's constructor. The shells in my example have no style flags and they all get a taskbar icon.
What is the best practice for subscribing to events from another JFrame? For example, I have a "settings" form, and when the user presses okay on the settings form, I want the main form to know about this so it can retrieve the settings.
Thanks.
Here is my ideal interface:
public void showSettingsButton_Click() {
frmSettings sForm = new sForm(this._currentSettings);
//sForm.btnOkay.Click = okayButtonClicked; // What to do here?
sForm.setVisible(true);
}
public void okayButtonClicked(frmSettings sForm) {
this._currentSettings = sForm.getSettings();
}
Someone publishes an Event, that something has changed, here the settings. A subscriber that registered for this specifig event, gets notified about it and can do his work, here get the settings. This is called publisher/subscriber.
For this you can use Eventbus or implementing something smaller on your own.
One approach is to have only a single JFrame. All the other 'free floating top level containers' could be modal dialogs. Access the the main GUI will be blocked until the current dialog is dismissed, and the code in the main frame can check the settings of the dialog after it is dismissed.
For anyone interested, here is what I ended up going with. I'm not sure if it's the best way, but it is working for my purposes.
// Method called when the "Show Settings" button is pressed from the main JFrame
private void showSettingsButton_Click() {
// Create new settings form and populate with my settings
frmSettings sForm = new frmSettings(this.mySettings);
// Get the "Save" button and register for its click event...
JButton btnSave = sForm.getSaveButton();
btnSave.addMouseListener(new MouseAdapter() {
#Override
public void mouseClicked(MouseEvent evt) {
SaveSettings(sForm);
}
});
// Show the settings form
sForm.setVisible(true);
}
// Method called whenever the save button is clicked on the settings form
private void SaveSettings(frmSettings sForm) {
// Get the new settings and assign them to the local member
Settings newSettings = sForm.getSettings();
this.mySettings = newSettings;
}
And if, like me, you are coming from a .NET perspective, here is the C# version:
private void showSettingsButton_Click(object sender, EventArgs e)
{
frmSettings sForm = new frmSettings(this.mySettings);
sForm.btnSave += new EventHandler(SaveSettings);
sForm.Show();
}
private void SaveSettings(object sender, EventArgs e)
{
frmSettings sForm = (frmSettings)sender; // This isn't the exact cast you need..
Settings newSettings = sForm.Settings;
this.mySettings = newSettings;
}
hi i have a full screen program which i dont want people to close unless they have a password i have this code at the moment
public void windowClosing(WindowEvent arg0)
{
System.out.println("HERE");
String inputValue = JOptionPane.showInputDialog("Please input the closeword");
if (inputValue != "closeplz")
{
}
}
in the if statement i want it to stop the method so that the program doesent close. any help would be greatly aprecheated thanks ste
You have to call
setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
on (or within) the JFrame instance. Then the frame will not close unless you do it manually, though windowClosing() will still be called. Inside it, you can then conditionally call
System.exit(1);
which will end the application. Be sure to do any necessary cleanup first.
Check out Closing an Applicaton for a simple class to help you with this. You would need to provide the custom close action that prompts the user for the password.
Using your simple example the code would be:
Action ca = new AbstractAction()
{
public void actionPerformed(ActionEvent e)
{
JFrame frame = (JFrame)e.getSource();
String inputValue = JOptionPane.showInputDialog("Please input the closeword");
if (! inputValue.equals("closeplz"))
{
frame.setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
}
}
};
CloseListener cl = new CloseListener(ca);
Is there a way to disable the Back button in a browser (basically clearing the History token stack) in GWT? Once I browse to a certain page in my application I want to make sure that the user can't use the back button to go back, but only be able to use links on the page to navigate the site.
You cannot disable a button just intercept it and change its return to something the browser does not understand.
This removes the history:
Window.addWindowClosingHandler(new ClosingHandler() {
#Override
public void onWindowClosing(ClosingEvent event) {
event.setMessage("My program");
}
});
To understand it see: http://groups.google.com/group/google-web-toolkit/browse_thread/thread/8b2a7ddad5a47af8/154ec7934eb6be42?lnk=gst&q=disable+back+button#154ec7934eb6be42
However, I would recommend not doing this because your it goes against good UI practices. Instead you should figure out a way that the back button does not cause a problem with your code.
Call the method below in the onModuleLoad().
private void setupHistory() {
final String initToken = History.getToken();
if (initToken.length() == 0) {
History.newItem("main");
}
// Add history listener
HandlerRegistration historyHandlerRegistration = History.addValueChangeHandler(new ValueChangeHandler() {
#Override
public void onValueChange(ValueChangeEvent event) {
String token = event.getValue();
if (initToken.equals(token)) {
History.newItem(initToken);
}
}
});
// Now that we've setup our listener, fire the initial history state.
History.fireCurrentHistoryState();
Window.addWindowClosingHandler(new ClosingHandler() {
boolean reloading = false;
#Override
public void onWindowClosing(ClosingEvent event) {
if (!reloading) {
String userAgent = Window.Navigator.getUserAgent();
if (userAgent.contains("MSIE")) {
if (!Window.confirm("Do you really want to exit?")) {
reloading = true;
Window.Location.reload(); // For IE
}
}
else {
event.setMessage("My App"); // For other browser
}
}
}
});
}
I found a way to make GWT ignore the back-button: Just add historyitem x if no historyitem was set and do nothing on x.
set a historyitem on startup
History.newItem("x")
in the ValueChangeHandler of History add the following:
String historyToken = event.getValue();
if (!historyToken.equals("x"))
History.newItem("x");
Window.addWindowClosingHandler(new ClosingHandler() {
#Override
public void onWindowClosing(ClosingEvent event) {
event.setMessage("My program");
}
});
That is not a fool proof solution. In fire fox I can press the back button and the onWindowClosing method is never invoked. The reason is that I have used History.newItem() and since history exists the back button or backspace buttons simply navigate through the browser history.
So....fix that :)
Put this in your index.html file:
window.open('html page(For example trial.html)', 'Name of the desired site', width='whatever you want',height='whatever you want', centerscreen=yes, menubar=no,toolbar=no,location=no,
personalbar=no, directories=no,status=no, resizable=yes, dependent=no, titlebar=no,dialog=no');