How can I direct ZK to display the "Processing..." message while handling an ON_CHANGING event?

asked 2013-04-14 15:57:39 +0800

eli gravatar image eli

Hello. My ZK 6.0.1 application shows a nice "Processing..." popup with spin-wheel when handling most events such as Events.ONCHANGE. But for spinners and double spinners I prefer to listen to ONCHANGING in order to give the user instant satisfaction. Sometimes the processing for ONCHANGING can take several seconds. I know this is bad but it can't be helped. Therefore I would like to have ZK show the "Processing..." popup during handling of ONCHANGING. But ZK does not not do it, I suppose b/c ON_CHANGING should be handled promptly. How can I override this behavior?


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answered 2013-04-15 09:51:34 +0800

gganassin gravatar image gganassin flag of Luxembourg
540 6

updated 2013-04-15 12:47:17 +0800

Inspired by EventQueue javadoc and its subscribe example: hope it's what you were looking for.

    public class ShowBusyController extends GenericForwardComposer {

    public void onSpinnerChanging(ForwardEvent event) {
        if (!desktop.isServerPushEnabled()) {

        final EventListener el = this;
        Clients.showBusy("wait a bit...");
        Thread bgThread = new Thread() {
            public void run() {
                try {
                } catch (InterruptedException e) {
                String result = "hello world!";
                Executions.schedule(desktop, el, new Event("onResultsAvailable", null, result));

    public void onResultsAvailable(Event event) {
        String result = (String) event.getData();

applied to

    <window title="long operation" border="normal" apply="tests.showbusy.ShowBusyController">
        <spinner forward="onChanging=onSpinnerChanging" />


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I appreciate this. ZK's EventQueue is nice. I use it in other situations. But I'm not seeing how it helps here. Still, much obliged and wish you well Giovanni.

eli ( 2013-04-16 02:50:15 +0800 )edit

Whoops sorry I forgot to edit the first sentence after I changed the code snippet. Anyway the code is consistent and it works... ;P

gganassin ( 2013-04-16 06:32:50 +0800 )edit
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Asked: 2013-04-14 15:57:39 +0800

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Last updated: Apr 15 '13

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