Question

I’ve built a log-in composite that I am displaying in my application entry-point to the user. Upon entry of the username and password, I am sending the username and password to the server via a RemoteService and will receive back an object containing the ClientSession. If the ClientSession is a valid object (recognised username and password), I wish to display the main application panel otherwise I want to display the login dialog again (with an error message).

My question is, that during the async call to the server, how to I mask the screen so that the user cannot click anything whilst the Session is obtained from the server?

I know that the login should be fast, but the Session object contains a lot of Client Side cached values for the current user that is used to generate the main panel. This may take a fraction of a second or up to 5 seconds (I can’t control the speed of the underlying infrastructure unfortunately) so I want to mask the screen until a timeout is reached then allow the user to try again.

I have done this exact operation before using GWT Ext, but vanilla GWT seems to have a lot less samples unfortunately.

Thanks

Chris

Answer 1

The GWT class PopupPanel has an optional “glass panel” that blocks interaction with the page underneath.

final PopupPanel popup = new PopupPanel(false, true); // Create a modal dialog box that will not auto-hide
popup.add(new Label("Please wait"));
popup.setGlassEnabled(true); // Enable the glass panel
popup.center(); // Center the popup and make it visible