adding Double click event in CellTable cell - GWT - events

Question

I am unable to figure out how could I add a double click event to the cell of the CellTable.
Is it possible with GWT CellTable or not?
Is there any workaround
thank you..
al
BTW, i saw this post but there is no reply...
http://www.devcomments.com/Adding-DoubleClicks-and-OnContextMenu-to-CellTable-at1066168.htm

Answer 1

I crafted something different that just fit my needs:
cellTable.addCellPreviewHandler(new Handler<TitoloProxy>() {
long lastClick=-1000;
#Override
public void onCellPreview(CellPreviewEvent<TitoloProxy> event) {
long clictAt = System.currentTimeMillis();
GWT.log("clickAt: "+(clictAt));
GWT.log("lastClick: "+(lastClick));
if(event.getNativeEvent().getType().contains("click")){
GWT.log(""+(clictAt-lastClick));
if(clictAt-lastClick < 300) { // dblclick on 2 clicks detected within 300 ms
Window.alert("I am a double click crafted event!");
}
lastClick = System.currentTimeMillis();
}
}
});

Answer 2

cellTable.addDomHandler(new DoubleClickHandler() {
#Override
public void onDoubleClick(DoubleClickEvent event) {
Window.alert("That's it!");
}
}, DoubleClickEvent.getType());

Answer 3

Integer row=0;// to hold row index
Integer column=0;// to hold column index
_Grid.addCellPreviewHandler(new CellPreviewEvent.Handler<Model>() {
// this is to handle row id
#Override
public void onCellPreview(final CellPreviewEvent<Model> event) {
if (BrowserEvents.CLICK.equalsIgnoreCase(event.getNativeEvent().getType())) {
row = event.getIndex();
column=event.getColumn();
}
}
});
// because Doubleclick handler doesn't give row index or column index we will use addCellPreviewHandler to return row index or column index.
_Grid.addDomHandler(new DoubleClickHandler() {
#Override
public void onDoubleClick(final DoubleClickEvent event) {
System.out.println(" You clicked row = " + row);
System.out.println(" You clicked column = " + column);
}
}, DoubleClickEvent.getType());

Answer 4

For cell lists, this code works ok:
cellList.addDomHandler(new DoubleClickHandler() {
#Override
public void onDoubleClick(DoubleClickEvent event) {
// do the stuff
}
}, DoubleClickEvent.getType());
I'm not sure about table cells

Answer 5

Because the CellPreview interface does not natively capture double click events you will need add event logic into the Overriden onCellPreview method. First you would think the best way would be to check the click time differences. However it is much more efficient and elegant to use a state machine and count clicks. This is more robust and allows you to deal with multiple event cases - Such as mouse hover, single, and double clicks. The code is pretty straightforward. So enjoy!
public class CellHoverHandler implements Handler<T> {
Timer singleClickTimer;
int clickCount = 0;
int clickDelay = 300;
#Override
public void onCellPreview(final CellPreviewEvent<T> event) {
if (Event.getTypeInt(event.getNativeEvent().getType()) == Event.ONMOUSEOVER) {
handleOnMouseOver(event);
} else if (Event.getTypeInt(event.getNativeEvent().getType()) == Event.ONCLICK) {
clickCount++;
if (clickCount == 1) {
singleClickTimer = new Timer() {
#Override
public void run() {
clickCount = 0;
handleOnClick(event);
}
};
singleClickTimer.schedule(clickDelay);
} else if (clickCount == 2) {
singleClickTimer.cancel();
clickCount = 0;
handleOnDblClick(event);
}
}
}
private void handleOnMouseOver(CellPreviewEvent<T> event) {
Element cell = event.getNativeEvent().getEventTarget().cast();
GWT.log("mouse over event");
}
private void handleOnClick(CellPreviewEvent<T> event) {
Element cell = event.getNativeEvent().getEventTarget().cast();
GWT.log("click event");
}
private void handleOnDblClick(CellPreviewEvent<T> event) {
Element cell = event.getNativeEvent().getEventTarget().cast();
GWT.log("double click event");
}
OPTIMIZATION: feel free to stick the count, timer, and delay as static class members or global members to reuse. Also check to see if the timer is null before making a new instance. I had omitted this for simplicity. Unlike a lot of other techniques this way still provides you with easy and direct access to the cell event. The technique with overloading the AbstractCell works well too, however sometimes you really don't have custom cells or want to make a custom cell to just handle events on the cell.

Answer 6

Leaving this here for future reference
private Set<GenericEventHandler<T>> dblClickHandlers = new HashSet<>(4);
dblClickHandlers simply maps interface implementations of my choice
table.addCellPreviewHandler(event -> {
if (BrowserEvents.DBLCLICK.equalsIgnoreCase(event.getNativeEvent().getType())) {
LOGGER.info("dblclick (native) " + event.getIndex() + " " + event.getColumn() + "; " + event.getValue());
dblClickHandlers.forEach(handler -> {
handler.onEvent(event.getValue());
});
}
});
table.sinkBitlessEvent(BrowserEvents.DBLCLICK);
The trick is to sink the 'dblclick' event.

Answer 7

If you wanted a text cell that allows you to support your own chosen list of events, you can use this:
public class EventfulTextCell extends AbstractSafeHtmlCell`<String`> {
private static final String[] NO_CONSUMED_EVENTS = null;
public EventfulTextCell() {
this(NO_CONSUMED_EVENTS);
}
public EventfulTextCell(String... consumedEvents) {
super(SimpleSafeHtmlRenderer.getInstance(), consumedEvents);
}
#Override
public void render(Context context, SafeHtml value, SafeHtmlBuilder sb) {
if (value != null) {
sb.append(value);
}
}
}
Then you instantiate it:
new EventfulTextCell("click", "dblclick")
Then override the onBrowserEvent() method to process your events.