How to show "Loading..." style of messages with long running tasks

General
1

I’m doing an application with long running searches and I would like to show a simple message with “Searching… please wait.” kind of feedback after search has been initiated.

How do I force an UI update? Is it possible to do it in same thread or do I need to spawn a new thread to do the search and then update the ui?
But then how do I force UI update after the search thread completes?

Example:


Button b = new Button("Search", new ClickListener() {
  // Show the info
  _infoDisplayAboutWorking.setVisible(true);
  // force UI update?

  // do the search...

  // OK, search done.
  _infoDisplayAboutWorking.setVisible(false);
});

Sorry if this is a beginners question - just started experimenting with the toolkit.

With kind regards,
-Mark

2

Hi Mark,

Basically, you don’t need to worry about updating the UI, but you have to poll the server to see if there are some pending updates there.

Here is a suggestion how to do this using the
ProgressIndicator
:


_infoDisplayAboutWorking.setVisible(true); 

// Use a ProgressIndicator to poll the server 
final ProgressIndicator poller = new ProgressIndicator(new Float(0.0)); 
poller.setPollingInterval(2000); // Poll server for changes every 2 secs
mylayout.addComponent(poller);

// Do the search in separate thread
Thread worker = new Thread() {
   public void run() {

      // do the search... 

      // OK, search done. 
      _infoDisplayAboutWorking.setVisible(false); 
      mylayout.removeComponent(poller);
   }
}
worker.start();

Here is also a post how to hide the indicator: http://forum.itmill.com/posts/list/606.page

3

Thank you - this works beautifully.

-Mark