I'm having trouble attaching an SelectionHandler to the contents of the mgwt HeaderList.
How can I attach a CellSelectedHandler to a HeaderList just like in the Showcase?
http://mobilegwt.appspot.com/showcase/#GroupedCellListPlace:
I already tryed to attach the Handler to the GrouingCellList with wich the HeaderList is built, but this Handler is never fired.
Anyone done this already?
I managed to get the SelectEvents using the SelectionHandler instead of the CellSelectedHandler on the GroupingCellList
addHandlerRegistration(view.getList().addSelectionHandler(new SelectionHandler<Content>(){
#Override
public void onSelection(SelectionEvent<Content> event) {
Window.alert("event"+event.getSelectedItem().getName());
}
}));
Related
My problem is with how to stop firing unrelated event of event bus. as I got this solution for Dialog box.
but it does not work in case of where one instance already initialize and try to create new instance of same class.
Just example: A below scroll panel has handler initialized. it used for document preview.
class TestScroll extends ScrollPanel
{
public TestScroll(){
}
implemented onload()
{
// eventBus.addHandler code here.
//here some preview related code
}
unload() method
{
//eventBus remove handler code
}
}
This preview has some data which contains some links that open different preview but with same class and different data structure,
Now The problem is like onUnload ( which contains code of remove handler) event does not load , because other panel opened. that does not mean previous panel unload.
So in that case, twice event handler registered. when one event fired then other event also fired.
Due to that, Preview 1 data shows properly, but after that Preview2 opened and when I close it, I find Preview1=Preview2.
so how can I handle such situation?
As per no of instance created each event fired. but I have to check some unique document id with if condition in event itself.
is there any other ways to stop unrelated event firing?
Edit:
public class Gwteventbus implements EntryPoint {
int i=0;
#Override
public void onModuleLoad() {
TestApp panel=new TestApp();
Button button=new Button("Test Event");
button.addClickHandler(new ClickHandler() {
#Override
public void onClick(ClickEvent event) {
TestApp panel=new TestApp();
int j=i;
new AppUtils().EVENT_BUS.fireEventFromSource(new AuthenticationEvent(),""+(j));
i++;
}
});
panel.add(button);
RootPanel.get().add(panel);
}
}
public class AppUtils {
public static EventBus EVENT_BUS = GWT.create(SimpleEventBus.class);
}
public class TestApp extends VerticalPanel{
String testString="";
public TestApp( ) {
AppUtils.EVENT_BUS.addHandler(AuthenticationEvent.TYPE, new AuthenticationEventHandler() {
#Override
public void onAuthenticationChanged(AuthenticationEvent authenticationEvent) {
System.out.println("helloworld"+authenticationEvent.getSource());
}
});
}
}
These are wild guesses as it's difficult to really answer it without code and a clear description.
I'm guessing you have one eventbus for all the panels. So when you register a handler it is registered with that one eventbus. In case you fire an event from one of the panels to the eventbus all panels will receive the event.
To fix this you can either create a new eventbus per panel or check who fired the event with event.getSource().
If this doesn't make sense you probably are reusing a variable or use a static variable which actually should be a new instance or none static variable.
You can use the GwtEventService-Library to fire specific events over a unique domain and every receiver that is registered at this domain receives that events then. You can handle as many different events/domains as you want.
In order to remove a handler attached to the EventBus, you must first store a reference to the HandlerRegistration returned by the addHandler method:
HandlerRegistration hr = eventBus.addHandler(new ClickHandler(){...});
Then you can remove the handler with the removeHandler method:
hr.removeHandler();
A final note worth mentioning is that when using singleton views, like is typical with MVP and GWT Activities and Places, it is best practice to make use of a ResettableEventBus. The eventBus passed to an activity's start() is just such a bus. When the ActivityManager stops the activity, it automatically removes all handlers attached to the ResettableEventBus.
I would strongly recommend reading the GWT Project's documentation on:
Activities and Places
Large scale application development and MVP
I'm trying to do the following:
I want to add a specific handler for some links, denoted by a class.
$("a.link_list").live("click", new ListLinkHandler());
I need .live() instead of .bind() because new such links will be generated. (I know jQuery's .live() is deprecated in favor of .on(), but gwt-query doesn't have a .on() yet.)
I defined the handler like this (just as the gwtquery example does):
public class ListLinkHandler extends Function {
#Override
public boolean f(Event e) { [...] }
}
However, the handler method is never called when I click the links.
I can see the event listener in Chrome Dev Tools: http://screencloud.net/v/bV5V. I think it's on the body because it's a .live().
I tried using .bind() and it worked fine. The body event listener changed in a a.link_list and the handler does what it's supposed to do, but (as documented, I didn't test) not for newly created links.
I filed a bug for the .live() method, but maybe I'm doing something wrong.
Also, I have no idea how to do it without gwtquery, GWT doesn't seem to have a method for selecting elements by class, neither to continually add the listener to new elements.
It seems you are doing something wrong, but I need more code to be sure. Could you send the complete onModuleLoad code which demonstrates this wrong behavior?
I have written a quick example using live, and it works either when adding new gwt widgets or dom elements with gquery, in both Chrome and FF
public void onModuleLoad() {
$("a.link_list").live("click", new ListLinkHandler());
// Add a new link via gquery
$("<a class='link_list' href=javascript:alert('href') onClick=alert('onClick')>Click </a>").appendTo(document);
// Add a new link via gwt widgets
Anchor a = new Anchor("click");
a.setStyleName("link_list");
a.addClickHandler(new ClickHandler() {
public void onClick(ClickEvent event) {
Window.alert("clickHandler");
}
});
RootPanel.get().add(a);
}
public class ListLinkHandler extends Function {
#Override
public boolean f(Event e) {
Window.alert("live");
return true;
}
}
I have added some extra functionality to the standard GWT ListBox by extending it like so:
public class FeatureListBox extends ListBox
{
public FeatureListBox()
{
}
public FeatureListBox(boolean isMultipleSelect)
{
super(isMultipleSelect);
}
public FeatureListBox(Element element)
{
super(element);
}
}
Nothing fancy here. However, the Change event is not firing now, or at least the handler (attached per below) is not getting invoked.
FeatureListBox listBox = new FeatureListBox();
listBox.addChangeHandler(new ChangeHandler()
{
public void onChange(ChangeEvent event)
{
// Do something here...
}
});
Any ideas why?
Either remove the no-argument constructor from FeatureListBox or call super() inside it, otherwise the initialization in the superclasses won't happen, which would probably result in what you're seeing.
The problem was in the way I was using my custom list box. In my application I wrap GWT Widgets around existing DOM elements on the page using the static wrap() methods of their widget classes in which the widgets get marked as attached, making them fire events. I didn't do that with my custom list box class originally, so I ended up implementing a static wrap() method similar to the one of the regular ListBox widget and using it in my code. Everything works like a charm now.
Hi I have been trying to reinitiate the data in a table by using an onClick handler
But when I click the data the older data persists and along with that the new data is coming up
Kindly let me know how can I resolve this issue
Thanks in advance
private void showErrorButton() {
//super.initWidget(widget);
_displayAlerts.addClickHandler(new ClickHandler() {
/**
* Click event for hiding dialog box.
*/
public void onClick(final ClickEvent arg0) {
getCustomDialog().getDialogBox().center();
getCustomDialog().getDialogBox().show();
showDialogBox(_errorList,_warnList);
}
});
}
It seems like you are not clearing the old data from your table before populating it with new data.
If you're using a Panel (GWT Javadoc) (or any subclass of Panel such as HTMLTable, FlexTable, etc.) you should call the method clear() before adding the new data.
void onClick(...) {
yourTable.clear();
yourTable.addNewData();
}
I'll change my answer as I learn more about your specific problem if this doesn't help.
lets say i have a custom widget which has a ClickHandler. Here's the example:
public class TestWidget extends Composite {
private static TestWidgetUiBinder uiBinder = GWT
.create(TestWidgetUiBinder.class);
interface TestWidgetUiBinder extends UiBinder<Widget, TestWidget> {
}
#UiField
Button button;
public TestWidget(String firstName) {
initWidget(uiBinder.createAndBindUi(this));
button.setText(firstName);
}
#UiHandler("button")
void onClick(ClickEvent e) {
Window.alert("Hello!");
}
}
When i try to add this Widget like this:
TestWidget testWidget = new TestWidget("myTestWidget");
RootPanel.get().add(testWidget);
everything is fine. If i click on my button i get the message i expect.
However if i add it like this:
TestWidget testWidget = new TestWidget("myTestWidget");
RootPanel.getBodyElement().appendChild(testWidget.getElement());
my click event is not being fired. I'm struggeling to understand why.
It would be nice if someone could explain this to me or link me to an resource where i can read this up. Finally i would like to know if it is possible to add the clickhandler afterwards i appended the child event and if that way is recommended. Thanks it advance for help.
kuku
When you call add(), Widget.onAttach() is called on the widget that is being added to the panel. onAttach does some work to register the widget to receive events. appendChild() simply attaches one DOM element to another and does nothing else. You should be able to get events working in the second case by doing this:
Element element = testWidget.getElement();
RootPanel.getBodyElement().appendChild(element);
DOM.sinkEvents(element,
Event.getTypeInt(ClickEvent.getType().getName())
| DOM.getEventsSunk(element);
However, I haven't tested this and I wouldn't recommend that you use it in a real application. Using add() is definitely preferred, using appendChild() in this way has no advantages and may lead to unexpected behaviour.