DDevelopment & Design

Easy firing click event from code in GWT

Firing native events in GWT can be a real pain. If you need to fire a click event when the user press ENTER (or any other key that you want to work like CLICK) on any custom-made element, theoretically you should use:

*DomEvent.fireNativeEvent(com.google.gwt.dom.client.NativeEvent, com.google.gwt.event.shared.HasHandlers) * Minimal code (without required parameters) linked with this approach: NativeEvent event = Document.get().createChangeEvent();
DomEvent.fireNativeEvent(event, this); public final NativeEvent createClickEvent(int detail, int screenX, int screenY, int clientX, int clientY, boolean ctrlKey, boolean altKey, boolean shiftKey, boolean metaKey) This is the place where native JSNI approach is much more clearer: public static native void click(Element element)/*-{
element.click();
}-*/;

This approach is very useful for custom made buttons that for some reason can not extend basic Button class. In any other case try not to simulate “user actions” in your handlers. Launch designated business methods instead.

— Previous article

<!--:pl-->Oddziały specjalne TouK na Topconf w Tallinnie<!--:--><!--:en-->TouK speakers' task force supports Topconf Tallinn<!--:-->

Next article —

TouK na turnieju beach soccera w Jarosławcu

You May Also Like
DDevelopment & Design

Grails render as JSON catch

One of a reasons your controller doesn't render a proper response in JSON format might be wrong package name that you use. It is easy to overlook. Import are on top of a file, you look at your code and everything seems to be fine. Except response is still not in JSON format.

Consider this simple controller:

class RestJsonCatchController {
def grailsJson() {
render([first: 'foo', second: 5] as grails.converters.JSON)
    }

def netSfJson() {
render([first: 'foo', second: 5] as net.sf.json.JSON)
    }
}

And now, with finger crossed... We have a winner!

$ curl localhost:8080/example/restJsonCatch/grailsJson
{"first":"foo","second":5}
$ curl localhost:8080/example/restJsonCatch/netSfJson
{first=foo, second=5}

As you can see only grails.converters.JSON converts your response to JSON format. There is no such converter for net.sf.json.JSON, so Grails has no converter to apply and it renders Map normally.

Conclusion: always carefully look at your imports if you're working with JSON in Grails!

Edit: Burt suggested that this is a bug. I've submitted JIRA issue here: GRAILS-9622 render as class that is not a codec should throw exception