On Wed, Feb 10, 2010 at 10:27 AM, Andi Mullaraj <andimulla...@gmail.com>wrote:
> I believe changing HMs mid stream is dangerous: > > 1. Say your (nav & edit) widget fires events that are common to both modes > (i.e. a simple onOpen) and the widget is by default in nav mode > 2 Say A registers an onOpen handler (which gets added to hm1 -- the default > HM) then later switches to edit mode (and hm2 kicks in) > 3. A will not see the onOpen events while on edit mode! > > If your nav & edit widet stays always in one mode, then createHM would do > the trick. But if it switches modes you have to make sure there is no > overlapping sets of events ... > Another option to achieve this with potentially less danger is to maintain a stack of HandlerManagers. If one HM doesn't handle an event, it goes down to the next one. Then, if you want to have some modal event handling logic, you push a new HM on the stack with its own set of event handlers. When you are done with the modal logic, you pop it off the stack. Event types not handled by the modal event handler fall through to the main one, so in your example onOpen would still get handled properly. -- John A. Tamplin Software Engineer (GWT), Google -- http://groups.google.com/group/Google-Web-Toolkit-Contributors
