Re: Destroy a widget

[Benjamin Possolo]

I can't really understand what you are asking or saying.

If you want the widget to remain visible but to stop receiving events, do 
what Jens said: suppress the event handling logic in the event handler.
If you want the widget to stop being visible and to stop receiving events, 
just do what I said: remove the widget from it's container.

and yes, javascript also has garbage collection otherwise every web 
application would be one giant memory leak

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Re: Destroy a widget

[Jose María Zaragoza]

El lunes, 29 de octubre de 2012 21:46:34 UTC+1, Jens escribió:
>
> When you create two HelloWorld widgets each of them receives its own 
> events. If you use @UiHandler in your UiBinder widget and you want to stop 
> receive events for a widget without removing the widget itself from the 
> parent (for whatever reason) you have to "disable" your @UiHandler 
> implementation.
>
> So you would end up having
>
> @UiHandler(...)
> void onEvent(...) {
>   if(handleEvents) {
>  //do your event logic
>   }
> }
>
> or you use a Delegate interface that a class can implement and that 
> contains your event logic implementation:
>
> @UiHandler(...)
> void onEvent(...) {
>   if(delegate != null) {
>  delegate.onEvent();
>   }
> }
>
> In that case you would disable your events by nulling your delegate: 
> widget.setDelegate(null)
>
>
> Otherwise you have to remove the widget from the parent.
>
>
> -- J.
>


Thanks for you answer. 
But  "to remove the widget from the parent." doesn`t avoid to receive 
events ( or my tests were wrong )

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Re: Destroy a widget

[Jose María Zaragoza]

>
> If you want to "destroy" h1, and have it stop reacting to events, simply 
> remove it from the dom and ensure it is garbage collected (ie. set your 
> reference to null):
>
> panel.remove(h1);
> h1 = null;
>

Thanks

Garbage collected? I thought that we were in a Javascript world
Setting to null doesn't work like I want because it's Javascript code.

And I don't want to remove it from a panel , but "destroy it" as entity. 
Maybe that doesn't have any sense, because I don't know how is implemented 
by GWT compiler into Javascript code, but  h1=null doesn`t work for me



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Re: Destroy a widget

[Jens]

When you create two HelloWorld widgets each of them receives its own 
events. If you use @UiHandler in your UiBinder widget and you want to stop 
receive events for a widget without removing the widget itself from the 
parent (for whatever reason) you have to "disable" your @UiHandler 
implementation.

So you would end up having

@UiHandler(...)
void onEvent(...) {
  if(handleEvents) {
 //do your event logic
  }
}

or you use a Delegate interface that a class can implement and that 
contains your event logic implementation:

@UiHandler(...)
void onEvent(...) {
  if(delegate != null) {
 delegate.onEvent();
  }
}

In that case you would disable your events by nulling your delegate: 
widget.setDelegate(null)


Otherwise you have to remove the widget from the parent.


-- J.

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Re: Destroy a widget

[Benjamin Possolo]

Sorry there is a typo there.

GWT.getRoot().add(panel);
should be
RootPanel.get().add(panel);

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Re: Destroy a widget

[Benjamin Possolo]

I presume by uibinder owner you mean your HelloWorld class overrides the 
onEvent() method, is that correct?

I also presume that you have some other component that is using the 
HelloWorld objects and attaching them to the view.
For example, in your EntryPoint:

HelloWorld h1 = new HelloWorld();
HelloWorld h2 = new HelloWorld();

FlowPanel panel = new FlowPanel();
panel.add(h1);
panel.add(h2);

GWT.getRoot().add(panel);

If you want to "destroy" h1, and have it stop reacting to events, simply 
remove it from the dom and ensure it is garbage collected (ie. set your 
reference to null):

panel.remove(h1);
h1 = null;

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Destroy a widget

[Jose María Zaragoza]

Hi:

I use GWT 2.3 and this question may sound a little bit weird 

I create a Widget component calling 
initWidget(uiBinder.createAndBindUi(this)) into  uibinder owner constructor 
method.

public HelloWorld()
 {
initWidget(uiBinder.createAndBindUi(this));
 }

Therefore, uibinder owner implements onEvent() to receive events

When I invoke 'new HelloWorld()'  , a new Widget
I don't know how GWT implements if I call many times  'new HelloWorld()'  , 
but if a event is fired , is received by all of them.

I'd like that if I do 

HelloWorld h1 = new HelloWorld();
HelloWorld h2 = new HelloWorld();

I could "to destroy" h1 such as when I do h1 = null in Java language, so 
new fired events only be received by h2
is it possible ?
I don't want to remove from parent , I want to destroy that reference , but 
I don't know how GWT implements it 

Thanks & regards








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