Question

I m optimizing a GWT application that previously used a variety of nested panels to work with DIVs and Spans. I generate the entire table as a single SafeHtml object and then assigning it into a single SafeHtml widget.

I now want to be able to track mouseover/mouseout events at the level of the specific cell spans rather than the entire table, but I m not sure how to do this.

如果我向超文本植被本身增加一名手,我便会从各种因素中获取活动。

Answer 1

Since 2.0 there is quite a simple way to do it. For example if you HTML code is contained in some kind of widget (HTMLPanel or HTML), you can calladdDomHandler(<handler>,<eventtyoe>) on that widget, so you will receive events from inner html. For example if you have a bunch of anchors inside HTMLPanel and you want to know which one was clicked you can do something like this:

panel.addDomHandler(new ClickHandler() {

        @Override
        public void onClick(ClickEvent event) {
            Element element=  event.getNativeEvent().getEventTarget().cast();
            if(element.getTagName().equals("A")) {
                AnchorElement anchor = element.cast();
                Window.alert("Anchor with href " + anchor.getHref() + " was clicked");
            }

        }
    }, ClickEvent.getType());

Since you want to track mouseover/out events you will have to use 2 different dom handlers, find out cell you need when event is fired and then change its state.

Answer 2

这样做的方法是:

Find the element you need with one of the DOM methods, like DOM.getElementById(..) or any other means. View Widget.getElement() etc.
Call DOOM.sinkEvents(element,eventBits) or DOM.sinkBitlessEvent(element,eventName) and pass the required events you want to sink in form of a bitmask, like Event.MOUSEEVENTS or using a named event like click or touchstart if using the second method.

同样:

DOM.setEventListener( element, new EventListener()
{

    @Override
    public void onBrowserEvent( Event event )
    {
        if ("click".event.getType()) {
           // ..do stuff..
        }
    }
} );

Only events you ve specified in step 2 will be fired to your EventListener, so you need to only handle those.

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