On 08/11/2011 08:38 AM, e-lena-s wrote:
> The issue is that the JS function is written by some other library.
> The custom event will be fired not by my module but by other code on
> the page . I however need to listen to that event, and get the
> customData out of that event for further processing within the
> module.
> I have tried to use DOM.sinkBitlessEvent (and seeing if I can catch
> this event in onBrowserEvent() ), but that didn't work. Not sure what
> other way I can get that event , or why does the custom event looses
> its customData when within JSNI method
Interesting problem.
Are you sure the event data is kept for the case of js --> js?
I'd eliminate that possibility first. I'm sure it works, but nothing
you've said so far positively eliminates that (admittedly small)
possibility.
If it /is/ kept, then:
0) write an event hander in js (i.e. outside gwt) that calls
addLookupResultHandler
1) load the event handler from step 0 as part of your external library's
load phase
2) hook your addLookupResultHandler to GWT's $wnd object before step 3)
3) fire the event in the library. That will call the event handler
written in step 0
>
>
> On Aug 11, 8:17 am, Jeffrey Chimene <jchim...@gmail.com> wrote:
>> On 8/10/2011 4:50 PM, e-lena-s wrote:
>>
>>
>>
>>
>>
>>
>>
>>> I am trying to listen to a custom JS event that is created outside my
>>> GWT module. In my JS file I create the event, and then fire it as
>>> such :
>>
>>> var evt = document.createEvent("Event");
>>> evt.initEvent('customEvent', true, true);
>>> evt.customData = "someData";
>>
>>> window.addEventListener('customEvent', function(evt)
>>> { console.log("test: " + evt.customData)}, false);
>>> window.dispatchEvent(evt);
>>
>>> Now, in my GWT code, I have a JSNI method that adds a listener to
>>> listen to my customEvent and act on it. Code as follows:
>>
>>> public native void addLookupResultHandler()/*-{
>>> $wnd.addEventListener('lookupEntitySelected',
>>> $entry(function(evt){
>>
>>> console.log("gwt: " + evt.customData);
>>
>>> console.log("gwt: " + evt.type);
>>
>>> @myClassName::handleEvent(LmyCustomEventEvent;)(evt)
>>> }), false);
>>> }-*/;
>>
>>> The problem I have is that the customData is being dropped when the
>>> event gets to JSNI code. I can see that the event listner written in
>>> JS does get the correct event with the correct customData, but logging
>>> the event properties in JSNI shows that customData is undefined (event
>>> type looks correct though)
>>
>>> Am I doing something wrong here ?
>>
>>> Is there may be a better way to create custom events (it has to be
>>> created in JavaScript, since the code firing it won't be in GWT
>>> module)
>>
>> My earlier answer was not correct. I don't see why
>> addLookupResultHandler is a JSNI routine. I think you want to write it
>> in GWT, via handling a NativeEvent. However, I've never tried this, so
>> it may not work as you intend.
>>
>> OTOH, maybe you should be using the GWT event bus. From an architectural
>> perspective, I think that's a better choice. Instead of using
>> window.dispatch(), fire the event via a JSNI method. So, your first JS
>> sample should become a JSNI routine that calls a Java routine that calls
>> eventBus.fire(), and your second example should become Java. It's
>> possible to call eventBus.fire() entirely within JSNI, but getting that
>> eventBus argument to your JSNI method may be problematic.
>
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