Develop Reference

Why Handler doesn't work while Listener does his job?

I struggle to catch events after famous DOM.appendChild. After many attempts of use handlers I found this answer where #Õzbek did the job via listener.
And now I don't get it why "listener" works while "handler" not.
As an example in code:
Button button = new Button("Test button");
DOM.appendChild(getElement(), button.getElement());
button.addClickHandler(new ClickHandler() {
#Override
public void onClick(ClickEvent event) {
GWT.log("this doesn't work");
}
});
DOM.sinkEvents(button.getElement(), Event.ONCLICK);
DOM.setEventListener(button.getElement(), new EventListener() {
public void onBrowserEvent(Event event) {
GWT.log("this works perfectly!");
}
});
the listener will be working but handler not.
So where is difference beetwen them?
And how to force handler to work?
Is there are some way to do this on handlers ?
I'm trying to understand the difference between listeners and handlers. I read these answers which shows that there is no big difference but I still don't get it

Button is a Widget not an element, and if you add it as an element to the dom you would lose the events. You can either append it to the RootPanel:
RootPanel.get().add(button) if you want to use the handler.
if you want to use the element not the widget you can use DOM.createButton(), and use the listener.

setEventListener of widgets is only called when they are "attached" (to a parent widget, which is itself attached, or delayed until it is attached), and you never "attach" the button.
With an explicit serEventListener you completely bypass the widget internals (and lifecycle). You could actually just use a ButtonElement in this case.
TL;DR: don't do that, it's a symptom of a broken design.

Gwtbootstrap3. Using bootstrap component only with java code- without ui-binder

Is there possibile to use bootstrap3 elements (from gwtboostrap3 library) without using ui binder, but using java code like it is done with gwt regular widgets?
I could not find a word about it in Documentation.
F.E. Lets take button widget from gwt:
public void onModuleLoad() {
// Make a new button that does something when you click it.
Button b = new Button("Jump!", new ClickHandler() {
public void onClick(ClickEvent event) {
Window.alert("How high?");
}
});
// Add it to the root panel.
RootPanel.get().add(b);
}
}
Which will create:
<button type="button" class="gwt-Button">Jump!</button>
In gwtbootstrap3 I have to do something like that:
<b:Button type="DEFAULT"/>
Please help me with that.
Is it possible to use gwtbootstrap3 library components like button with pure java instead of uibinder xml files?
Is there solution that works out of box?
Or maybe I should write my own classess that extends native gwt widget an add bootstrap releated css classes?

Yes!
You can use the widget as you please, refer to the their javadoc to see what constructors they have! They are a different set of widgets and might not be analogue of GWT standard widgets.
Bonus
GWT UiBinder does no different than you, all it does is reduce the boilerplate, generating java classes that automate the instantiate of the widgets. You can add the compiler option -gen to see these transient classes. Usually , they are deleted after GWT compiles your application, as they are no longer needed. Take a look the the compiler documentation for more info!

Is it possible to add a message bar/ toolbar at the bottom of a titleareadialog?

With my TitleAreaDialog is it possible to add a area or a bar across the bottom, below the buttons. That a message can be displayed to the users, when a operation is taking place.
Here is a example of what I am referring to

AFAIK, this is not possible for JFace Dialogs. Depending on what exactly you are doing, you might want to have a look at JFace ApplicationWindow. This class has a method addStatusLine(). You would have to override the following method:
#Override
protected StatusLineManager createStatusLineManager() {
StatusLineManager statusLineManager = new StatusLineManager();
statusLineManager.setMessage(null, "YOUR_MESSAGE");
return statusLineManager;
}
You can change the text with:
getStatusLineManager().setMessage("YOUR_NEW_MESSAGE");
Here is an excellent overview of the ApplicationWindow class.

DJ JWebBrowser: how to show but disable Address and Button bars?

I am using chrriis.dj.nativeswing.swtimpl.components.JWebBrowser in my swing application to open web page.
The page is going to show "Facebook Authentication" page and I want to prevent user from inputting some other URL other than I specify and also Forward and Back buttons should be visible but not has no affect.
So following functions are applicable for my goal
setButtonBarVisible(false);
setLocationBarVisible(false);
Once user completes the authentication I will handle the locationChanged event.
#Override
public void locationChanged(WebBrowserNavigationEvent arg0) {
System.out.println("locationChanged!");
....
}
}

I think what you want is a custom decorator. Check the demo application, under "JWebBrowser > Custom Decorator".
In your case, you could create a new decorator class, as an adapted copy of DefaultWebBrowserDecorator or a subclass with appropriate override.
You would also have to decide if this decorator is to be used only by one instance of the JWebBrowser or all instances (like child popups, etc.)

Wicket AJAX + OnComponentTag

HI guys,
I wanted to add an AJAX Event to my Homepage, but it doesn't work! I figured out, that if I delete the onComponentTag function it works well. I have no clue why this happend, maybe you can help me!
Thats my Code:
final TextField<String> searchInput = new TextField<String>("searchInput", model) {
#Override
protected void onComponentTag(final ComponentTag tag) {
super.onComponentTag(tag);
tag.put("id", this.getId());
if (params.getString("search") != null) {
tag.put("value", params.getString("search"));
}
}
};
searchInput.add(new AjaxFormComponentUpdatingBehavior("onfocus") {
#Override
protected void onUpdate(final AjaxRequestTarget target) {
System.out.print("never saw that message :(");
searchInput.setDefaultModelObject("");
target.addComponent(searchInput);
}
});
Thx a lot for helping me!
CU

Firstly, you don't need to be overriding onComponentTag() at all. As seanizer states, if your really need to specify a markup ID yourself, use setMarkupId(id). You should understand why it is recommended that Wicket manages component IDs.
Secondly, the value attribute that you are adding is unnecessary - Wicket adds this automatically for this component. The value assigned is the value of the component's model object. See the source for TextField.onComponentTag().
Thirdly, again as seanizer states, components that are to be updated by ajax need to output their markup IDs - Wicket's ajax implementation uses the ID as the selector for the element. Additionally, all Wicket ajax behaviours that extend AbstractDefaultAjaxBehavior automatically set outputMarkupId(true) on the component they are bound to (see the source for AbstractDefaultAjaxBehavior.onBind()). This includes AjaxFormComponentUpdatingBehavior.
So:
String id = "searchInput";
final TextField<String> searchInput = new TextField<String>(id, model);
searchInput.setMarkupId(id);
searchInput.add(new AjaxFormComponentUpdatingBehavior("onfocus") {
#Override
protected void onUpdate(final AjaxRequestTarget target) {
System.out.print("never saw that message :(");
searchInput.setDefaultModelObject("");
target.setOutputMarkupId(true);
target.addComponent(searchInput);
}
});
Finally, I'd question what you're actually trying to achieve with this behaviour. I don't see any reason to round-trip this event to the server. Surely some client-side JS is more appropriate?

tag.put("id", this.getId());
is not the way to do it in wicket.
instead, use
component.setOutputMarkupId(true)
(either in your component constructor or in your behavior's bind() method) to make wicket write the id, and if you absolutely need to control what the id is (which is almost never the case) you can do
component.setMarkupId("myId")
also, you probably shouldn't assign the tag value yourself, use a model (model handling is extremely smart in wicket, read more about models). There are valid uses for onComponentTag, but they are way beyond what you are doing. Let wicket do what wicket does best and everything will be fine.
EDIT:
OK, some more clarification
have a look at the source code of AjaxFormComponentUpdatingBehavior, especially the part where the javascript event handler is generated.
protected final CharSequence getEventHandler()
{
return generateCallbackScript(
new AppendingStringBuffer("wicketAjaxPost('")
.append(getCallbackUrl(false)).append(
"', wicketSerialize(Wicket.$('"
+ getComponent().getMarkupId() + "'))"));
}
as you can see, wicket uses getMarkupId() to determine the actual id. The id you set using tag.put(id) is totally unknown to wicket and hence the behavior cannot work.
The standard thing to do is setOutputMarkupId(true). This is the only proper way to tell wicket to render the id (other than setOutputMarkupPlaceholder(true), which internally calls the former method). That way you make sure that the id wicket writes is the id wicket knows about. If this doesn't render the id, you are probably breaking some default behavior by overwriting onComponentTag.
Have a look at the source code of Component, especially at onComponentTag(), the method you are overriding:
protected void onComponentTag(final ComponentTag tag) {
// if(setOutputMarkupId(true) was set)
if (getFlag(FLAG_OUTPUT_MARKUP_ID)) {
// set id attribute
tag.put(MARKUP_ID_ATTR_NAME, getMarkupId());
}
}
[The comments are mine. BTW, this is the source of an ancient version, but I didn't find any current source online, and the functionality hasn't changed.]
Now if, as in your case, you want to set the component id manually, you must use
component.setMarkupId("myId")
and of course
setOutputMarkupId(true)
as well. If that doesn't work, go to the wicket JIRA site and file a bug. But I doubt it, this is standard functionality that works for thousands of users.