Does anybody have an idea on how I can accomplish this using Wicket?
I want to display a Wicket odal window automatically when no user activity has been detected for a certain amount of time. I'm thinking of using an AjaxSelfUpdatingBehavior in some way, but I have no clear ideas actually.
Is this possible with Wicket?
Also, you can use some js library not to catch all ajax calls and to be sure, that your user is really afk (even does not touching his mouse).
For example, see this free framework and it's demo.
And (if you using this js framework) in wicket you must handle
ifvisible.idle(function(){
Wicket.Ajax.get({u: '${callbackUrl}'})// This code will work when page goes into idle status
});
You must set ${callbackUrl} from wicket code to let js know what action to proceed in java code. It is not hard to do this. Look here.
This approach is more tricky, but if you implement this, you don't have to worry about users actions at all (he can read site's info and don't click any ajax links, but suddenly he will see modal window).
Yes you can, I use this as autologout function
public class MyTimer extends AbstractAjaxTimerBehavior {
public MyTimer(int seconds) {
this(Duration.seconds(seconds));
}
#Override
protected void onTimer(AjaxRequestTarget target) {
// show your window magic
}
}
Add this to you page (add(new MyTimer(300));) and this will be called after the number of seconds you specify. Make sure to replace the timer with a new one when doing ajax calls, or reset it.
Related
First off, before the flames start, I do know that trying to hinder the back button in the browser is a dumb idea. I would not try to do this, but my business partners are very insistent on it. We are porting an existing .exe to the web and their definition of this is 'run it in a browser' and not "make it a web site". So, fact that it's a bad idea (I agree), here's the question:
Is there a way to ignore or trick the GWT PlaceController / History manager mechanisms so that when the back button is pressed, it just stays on the same page?
I have used Window.addWindowClosingHandler to add a handler which will prompt the user if they want to leave the page and overriden the newItem() method of the defaultHistorian so that no history is tracked at all, but this isn't quite what the business people want.
What they'd like is to just ignore the back button so that nothing happens when it is clicked.
If anyone knows how to do this with GWT, I'd be very grateful.
And I"ve done a lot of google searching and haven't found anything exactly like this question. At least, not close enough to help.
I was able to get GWT to not accumulate any history so that when the user presses the BACK button, they cause an onWindowClosing event to happen and the Browser will prompt them if they want to stay or leave. This will accomplish the goal of not allowing the BACK button to take them back, but it's a bit Draconian. This code does that:
class TvHistorian extends PlaceHistoryHandler.DefaultHistorian
{
#Override
public void newItem(String token, boolean issueEvent) {
// don't do anything - this will prevent history from accumulating
}
}
final PlaceHistoryHandler historyHandler = new PlaceHistoryHandler(historyMapper, new TvHistorian());
I've tried a bunch of stuff including extending the PlaceController.goTo() to save the "lastNormalFlowPlace". Then, I tried to override the History.onValueChange to use this saved Place if it was different than what the event specified. But I think I missed some subtlety because that didn't work as expected.
With the above exception, my code looks almost exactly like what is documented here: http://www.gwtproject.org/doc/latest/DevGuideMvpActivitiesAndPlaces.html#Putting_it_all_together
I have already posted an answer in the same context.
Please have a look at below links:
promt user on backspace and browser backbutton in gwt
how can i get a prompt on url change
Disable back button in GWT
Try with any option:
History.addValueChangeHandler
WindowClosingHandler
Event.addNativePreviewHandler
$wnd.onbeforeunload
--EDIT--
Sample code: (It's working perfectly fine in Firefox, Chrome as well as IE9)
Note: add below code in the beginning of the onModuleLoad() method.
final String initToken = "Place";
History.addValueChangeHandler(new ValueChangeHandler<String>() {
#Override
public void onValueChange(ValueChangeEvent<String> event) {
String token = event.getValue();
if (!initToken.equalsIgnoreCase(token)) {
History.newItem(initToken);
}
}
});
// fire the initial history state.
History.fireCurrentHistoryState();
Note: add checks for other allowed history tokens.
I have a hook on the beforeUnload event. If i try to click on a link, reload or close the tab or the navigator, the app ask for confirmation before leaving. That's the desired behavior.
But if click on the back button or the backspace outside an input, no confirmation.
At the beginning of the html :
window.onbeforeunload = function() {
if (confirmEnabled)
return "";
}
And i use the Gwt PlaceHistoryMapper.
What did i miss ? Where did i forgot to look ?
Thanks !
As long as you stay within your app, because it's a single-page app, it doesn't by definition unload, so there's no beforeunload event.
When using Places, the equivalent is the PlaceChangeRequestEvent dispatched by the PlaceController on the EventBus. This event is also dispatched in beforeunload BTW, and is the basis for the mayStop() handling in Activities.
Outside GWT, in the JS world, an equivalent would be hashchange and/or popstate, depending on your PlaceHistoryHandler.Historian implementation (the default one uses History.newItem(), so that would be hashchange).
I have a question regarding the event handling on client side in GWT.
In our application we have a quite complex structure of different modules and pages which are communicating via the gwt eventbus on client side. Now the amount of events is growing to fast for my opinion. E.g. I am opening a popup I need:
An event for opening the popup
An event for asking some data within the client
An event for getting back the data and fill in the dialog
An event for closing the popup
An event for handling the save Button
Am I thinking a little bit to complicated or missing something in the EventBus implementation? I just wanted to have some feedback out of the community as you are facing the same issues.
For what it's worth, I have lots of events and more growing. And yes, I wonder if I can do with less, but when I skip an event and link elements directly, I regret it.
Here's an example that I just fixed up yesterday. I have a DataGrid widget. I also support re-ordering of columns, hiding of columns, re-sizing columns, and coloring columns with a popup dialog. You click on a configure button, and a popup with the columns listed shows, and the user can click checkboxes to show or hide columns, click on a Move Up / Move Down button to re-order columns, and so on. Hit Apply on the popup and the popup disappears and the DataGrid re-configures.
Except that it didn't. You'd click on Apply and the popup would just sit there, the user would wonder what was going on, the DataGrid would re-configure underneath, and then the popup would go away. We're only talking a short amount of time -- maybe a second or a bit more -- but it was so so noticeable. Why was it happening? Because I got lazy and tied the popup directly to the configure button, and the Apply button directly to the DataGrid. You'd hit Apply, for example, and the call would be made to the DataGrid with the new configuration information. Only when the call returned would the popup would be torn down.
I knew it was bad when I did it, but I was being lazy. So I took the 20 minutes I needed to write up two messages and associated handlers in my mediator singleton. One message is issued by the DataGrid to start the configuration dialog, and one is issued by the popup to configure the DataGrid. Now the widgets are de-coupled, and the performance is much snappier. There is no sense of "stickiness".
Now to your example, can you not combine (1) and (2)? And also (3), (4), and (5)? When the user clicks the configure button on my app, the event carries with it the current configuration information (including a reference to the DataGrid that originated the request). You can call this information the "payload". When the user clicks the Apply button on the popup, the event payload includes all the new configuration information (including a reference to that original target DataGrid) that the event handler feeds to the target DataGrid when the event is handled. Two events -- one to kick off the configuration and one to apply the end result.
Yes there are a plethora of events in any app that does something interesting, but events can carry a lot of information, so I would look at whether your event organization is too fractured.
As a extra bit, here is the code I use. I shamelessly copied elements of this pattern from one of Google's examples.
The user can ask for help using a menu item:
#UiField
MenuItem help;
help.setCommand(new Command() {
#Override
public void execute() {
BagOfState.getInstance().getCommonEventBus().fireEvent(new MenuHelpEvent());
}
});
For the event (in this case, the event fired when the user clicks on the Help menu item):
public class MenuHelpEvent extends GwtEvent<MenuHelpEvent.Handler> {
private static final Type<Handler> TYPE = new Type<Handler>();
public interface Handler extends EventHandler {
void doMenuHelp();
}
#Override
public GwtEvent.Type<Handler> getAssociatedType() {
return TYPE;
}
#Override
protected void dispatch(Handler handler) {
handler.doMenuHelp();
}
public static HandlerRegistration register(EventBus eventBus, Handler handler) {
return eventBus.addHandler(TYPE, handler);
}
}
I have a singleton called Mediator in which ALL events are registered:
MenuHelpEvent.register(BagOfState.getInstance().getCommonEventBus(),
new MenuHelpEvent.Handler() {
#Override
public void doMenuHelp() {
new MenuHelp().execute();
}
});
Every event is mated with a Command object to do the work:
public class MenuHelp implements Command {
#Override
public void execute() {
new InfoMessage(BagOfState.APP_MSG.unimplementedFeatureCaption())
.setTextAndCenter(BagOfState.APP_MSG.unimplementedFeature());
}
}
Everything is decoupled. The menu widget is bound to a command that executes and then completes. The command fires the event on the bus then completes. The event fires off the execution of a Command and the completes. The Command shows the popup help panel (in this case, an "unimplemented" message to the user -- yeah, I'll get to it soon). Every interaction with a user's input is handled extremely quickly and resolves. It can kick off a series of events to perform a long action, but never tying up the GUI to do so. And of course, since the elements are decoupled, I can call the same elements in other places (for instance, call the help Command through a button push as well as a menu item).
As we are facing GWT performance issues in a mobile app I peeked into Google Wave code since it is developed with GWT.
I thought that all the buttons there are widgets but if you look into generated HTML with firebug you see no onclick attribute set on clickable divs. I wonder how they achieve it having an element that issues click or mousedown events and seemingly neither being a widget nor injected with onclick attribute.
Being able to create such components would surely take me one step further to optimizing performance.
Thanks.
ps: wasnt google going to open source client code too. Have not been able to find it.
You don't have to put an onclick attribute on the HTML to make it have an onclick handler. This is a very simple example:
<div id="mydiv">Regular old div</div>
Then in script:
document.getElementById('mydiv').onclick = function() {
alert('hello!');
}
They wouldn't set the onclick property directly, it would have been set in the GWT code or via another Javascript library.
The GWT documentation shows how to create handlers within a GWT Java app:
public void anonClickHandlerExample() {
Button b = new Button("Click Me");
b.addClickHandler(new ClickHandler() {
public void onClick(ClickEvent event) {
// handle the click event
}
});
}
This will generate an HTML element and bind a click handler to it. However, in practice this has the same result as using document.getElementById('element').onclick() on an existing element in your page.
You can hook functions to the onclick event using JavaScript. Here's an example using jQuery:
$(document).ready(function(){
$("#div-id").click(function(){
/* Do something */
});
});
If you're interested in optimizing performance around this, you may need to investigate event delegation, depending on your situation.
A click event is generated for every DOM element within the Body. The event travels from the Body down to the element clicked (unless you are using Internet Explorer), hits the element clicked, and then bubbles back up. The event can be captured either through DOM element attributes, event handlers in the javascript, or attributes at any of the parent levels (the bubbling or capturing event triggers this).
I'd imagine they've just set it in a .js file.
Easily done with say jQuery with $(document).ready() for example.
im new to GWT ive been working on it since recently..
i want to know how can i go from "entry point page" ie,ImageViewer.java..
ive been suggested to create the memory by calling constructor on a perticular button
Button button = new Button("New button");
button.addClickHandler(new ClickHandler() {
public void onClick(ClickEvent event)
{
new LookupMaster(); //this is a composite
}
});
but this is not working.. i guess v can only call or get alert messages using this type..
can some one help me.
I'm not sure how to answer, since I have the feeling you're not understanding the basic concepts totally, but that's just my interpretation.
GWT is one html page that via JavaScript methods changes the content of that one page. When you want to display 'another' page you need to do this via methods that update the html dynamically. Since you are just starting with GWT, you might want to read this page on Build User Interfaces to understand the concepts and look at some examples provided with GWT.