I want to show a modal window (instead the confirm) when a user close the browser. The GWT documention remarks that (during the handler operation) no user UI may be displayed during the shutdown. Exists any way cancel the operation, from the client not from the user?
Thanks in advance,
Oscar.
You can't cancel the close event. The best you can do is to let the user press cancel. I think the reason for this is to prevent "bad" javascript from not letting you close your browser.
This displays a dialog with a cancel option.
Window.addWindowCloseListener(new WindowCloseListener()
{
public String onWindowClosing()
{
return "You are about to exit from the application. Are you sure?";
}
public void onWindowClosed()
{
//cleanup code
}
});
Related
Is there a reliable way to detect the closing of the browser tab or window on the server side in a wicket application?
It must work under firefox version 68.11.0 or higher. I use wicket 8.8.0.
I tried it with websockets and catching the connection close event. But unfortunately this event is also raised when a page is refreshed (F5).
new WebSocketBehavior() {
#Override
protected void onClose(ClosedMessage message) { // invoked on tab close, window close and unfortunately on page reload
super.onClose(message);
log.info("Connection for page = '{}' closed.", message.getKey());
}
}
From browser point of view there is no difference between closing the tab and refreshing the tab. In both cases the browser fires beforeunload JavaScript event and closes all open connections (WebSocket, ServerSideEvent, Ajax).
So, you can use
page.add(new AjaxEventBehavior("beforeunload") {
#Override public void onEvent(AjaxRequestTarget target) {...}
});
but this just tell you that the user navigates away from the current page. There is no info what comes next.
I'm having an issue handling the forward button.
Basically, when a user is on a page and has made changes without saving then presses the backwards or forwards button they are presented with a prompt and two options: Leave or Stay.
I have implemented the backwards button fine, and choosing to stay on the page works well using History.newItem(currentToken) - the back button is still clickable.
However with the forwards button, if I use History.newItem(currentToken), it brings this to the front of the history stack and the forward button can no longer be clicked.
History.replaceItem(currentToken) causes the same issue.
How do I handle the cancelling of a forwards action so that I stay on my current page, but the forwards button is still enabled?
#Override
public void onValueChange(ValueChangeEvent<String> event) {
logger.info("back button pressed: " + event.getValue());
String evenVal = event.getValue();
String token = History.getToken();
AbstractPresenter presenter = sessionKiosk.getCurrentlyShowingPresenter();
if (presenter instanceof NSRCommonWorksheetPresenter && sessionKiosk.isDirty()) {
((NSRCommonWorksheetPresenter)presenter).setHistoryToken(event.getValue());
((NSRCommonWorksheetPresenter)presenter).showUnsavedChangesLeavingPageDialog();
}
else {
handleHistoryEvent(event.getValue());
}
}
The dialog is shown and when I click on stay on page the following is called.
public void stayOnCurrentPage() {
if (eventMap.get(prevPage) != null) {
History.newItem(prevPage, false);
}
}
Update: Basically history.newItem(value) removes the use of the forward button. Is there another way to cancel the event? If I just do nothing, th page stays where i want but the url still updates
None of the 3 options in the else statement seem to work.
Thanks.
You can simply cancel the event without touching History or tokens.
UPDATE:
It appears from your code that you are not intercepting the event (back/forward button), but let it go through, get the new token, and then force a return to the previous state under certain circumstances.
I suggest using Activities and Places pattern where every "place" within your app has a corresponding "activity". Each activity in your app will implement GWT Activity interface which includes mayStop() method. This method is called before a user navigates away from a specific place in your app, giving you an opportunity to warn a user and cancel the navigation if necessary.
In general, this pattern offers a very robust support for the History mechanism, covering many use cases.
If you want to support History mechanism yourself, take a look at PlaceChangeRequestEvent - it allows you to warn a user who tries to navigate away from a place in your app.
when i click on a button the click event handler executes a code . If by mistake(if browser hangs) i click on the button twice the code gets executed twice.i dont want that to happen.
Any suggestions to stop that?
i suppose i should use a schedular or timer but i am not sure
below is the code:
public void onSendButtonClicked() {
disableButtons();
eventBus.fireEvent(new SendEmcsDeclarationEvent(getDeclaration(), getMsgType()));
}
You can - as Abdullah mentioned - disable/enable every widget in GWT with
widget.setEnable(false)
and
widget.setEnable(true).
If you want to lock the whole screen, create a modal popup, show it, after the button is pressed and hide it, after the code has finished.
public void onSendButtonClicked() {
myProgessBar.show();
eventBus.fireEvent(new SendEmcsDeclarationEvent(getDeclaration(), getMsgType()));
myProgressBar.hide();
}
If you are using a async call, you have to hide the progessbar in the callbacks. In this case the finally command might be executed before the callback is executed. In your case it might be a good idea to create a ShowProgressBarEvent and HideProgressbarEvent, so that you can use the progressbar in your whole application.
If your are using a widget library f.e.: GXT, you will find a ProgressBar ready to use.
Hope that helps.
The best way I can think of is to enable/disable the button itself so as to make sure that the code in handler is not called again until before the previous call finishes up.
public void onSendButtonClicked()
{
try
{
disableButtons();
eventBus.fireEvent(new SendEmcsDeclarationEvent(getDeclaration(), getMsgType()));
}
catch (Exception ex)
{
throw ex;
}
finally
{
enableButtons();
}
}
When I create a button, I always also add an animating gif (ajaxloader).
When the button is clicked I make the button invisble, the ajaxloader visible.
When the action is done, I make the ajaxloader invisible, and the button visible.
This way the user has some visual feedback that something is happening (what you don't get when disabling the button), and not the entire application gets blocked (as a modal does) which is one of the plus points using ajax.
i am using GWT. on window close we get browser provided message" Are you sure you want to navigate away from this page?". i want to replace the message with my own message. please help me. below is my code.
Window.addWindowClosingHandler(new Window.ClosingHandler() {
#Override
public void onWindowClosing(final Window.ClosingEvent closingEvent) {
closingEvent.setMessage("some message.");
}
});
you can not modify the dialog that is opened if you provide a string in the closing event.
The dialog is handled by the browser and can not be customized.
I have a web app that uses GXT (version 1.2.2) grids extensively. I'd like to warn the user if they make changes but don't save.
When I use the grid in a popup dialog, the only way for the user to leave is via a button (either Close or OK). If I add a SelectionListener to the Close button, I can do my "isDirty()" check and warn the user.
If I am not using a dialog, the restriction for leaving the page isn't there. The user can click on a side menu, select a different tab, hit a refresh or next page button that we have on each page. I could listen for an event on everyone of those, but is there an easier way? Something like a "before unload" event that gets fired?
Window.addCloseListener
Or in GWT 1.6:
Window.addCloseHandler
You cannot prevent the window from closing, but you can prompt the user to click cancel which will leave the page open. You can also perform a last-chance save operation after the user chooses to confirm the window close, but before your page is unloaded.
Try this:
Window.addListener(Events.Close,
new Listener<ComponentEvent>() {
public void handleEvent(ComponentEvent be) {
//Do something
}
});
or
Window.addListener(Events.Detach,
new Listener<ComponentEvent>() {
public void handleEvent(ComponentEvent be) {
//Do something
}
});