gwt:adding clickhandler to ImageResource cell - gwt

Question

I want to add an image to my celltable , for that i use imageResouce as below
interface Resources extends ClientBundle {
#Source("close.png")
ImageResource getImageResource();
}
Resources resources = GWT.create(Resources.class);
deleteJobColumn = new Column<EmployerJobs, ImageResource>(new ImageResourceCell()) {
#Override
public ImageResource getValue(EmployerJobs object) {
return resources.getImageResource();
}
};
Its working perfectly fine , i am getting image in my celltable but Now i want to add clickhandler to that image ,For that i am using field Updater like below
display.getListJobsWidget().getDeleteJobColumn().setFieldUpdater(
new FieldUpdater<EmployerJobs, ImageResource>() {
public void update(int index, EmployerJobs employerJobs,
ImageResource value) {
Window.alert("Hello");
}
});
so now when i click on that above image cell it should say "Hello", but its not doing any thing .. Any solution ..
Thanks

Answer 1

ImageResourceCell doesn't have any wiring to call the ValueUpdater, it is just designed to draw the image and be done with it.
You have a few ways you can change this:
Subclass ImageResourceCell and override onBrowserEvent - take a look at ButtonCell to see how this can work
Use a different cell class instead, like ActionCell - this doesn't take any data from the client, but will let you pass in a delegate isntead, which will be run when the thing is clicked. Use the ActionCell(SafeHtml,Delegate<C>) constructor to pass in your image, in the form of html
Build a new cell, subclassing AbstractCell, borrowing the render code from ImageResourceCell and the event code from ButtonCell or ActionCell to keep your code as generic and reusable as possible.

Answer 2

An example for the first solution provided by Colin. I found it a bit tricky to override getConsumedEvents but seems to work well.
public class ClickableImageResourceCell extends ImageResourceCell{
public ClickableImageResourceCell(){
super();
}
#Override
public Set<String> getConsumedEvents() {
Set<String> set = new HashSet<String>();
set.add("click");
return set;
}
#Override
public void onBrowserEvent(com.google.gwt.cell.client.Cell.Context context, Element parent, ImageResource value, NativeEvent event, ValueUpdater<ImageResource> valueUpdater) {
super.onBrowserEvent(context, parent, value, event, valueUpdater);
if ("click".equals(event.getType())) {
EventTarget eventTarget = event.getEventTarget();
if (!Element.is(eventTarget)) {
return;
}
if (parent.getFirstChildElement().isOrHasChild(Element.as(eventTarget))) {
// Ignore clicks that occur outside of the main element.
keyDown(context, parent, value, event, valueUpdater);
}
}
}
protected void keyDown(Context context, Element parent, ImageResource value,
NativeEvent event, ValueUpdater<ImageResource> valueUpdater) {
if (valueUpdater != null) {
valueUpdater.update(value);
}
}
}