Friday, July 22, 2016

Re: How to detect the scrollpanel is still scrolling or not in GWT?

I think the generally adopted pattern is to schedule a task 100 or 250ms away, and reschedule it on each scroll event (use a c.g.g.user.client.Timer to be able to reschedule it).
Ideally, you'd also use a "passive event listener", but GWT doesn't expose it: (you'd have to use JSNI, which is prone to errors, browser incompatibilities, and memory leaks)

BTW, I almost never use the "scrollbar", I use mousewheel on laptop/desktop and touch on mobile/tablet.

On Friday, July 22, 2016 at 8:27:37 AM UTC+2, shiva raaj wrote:
Thanks for response. But I need consider last request only. Basically I need to skip(eaten) all the previous request. I have logic to eat the request.But Is there any way to find out scroll bar is still scrolling without release the bar.

Thank U

On Thursday, 21 July 2016 18:18:25 UTC+5:30, Gilberto wrote:
I don't know if that helps with your problem, but you could leave the events as they are today and only make new requests to the server when the previous one were executed.

Something like this:

private boolean requestingServer = false;

public void onScroll(ScrollEvent scrollEvent) {
if (requestingServer) return;
    requestingServer = true;
    doServerRequest(new Callback(){ //pseudo code here for a callback mechanism
        public void onResponse(Payload something){
requestingServer = false;

You can add a logic for a minimum delay between requests as well.

This kind of code works on GWT because it is single threaded. In pure Java you would need to create synchronized blocks to ensure that only one request is being made to the server.

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