It seems I can answer my own question now: The OSDE Eclipse plugin seems to do pretty much what I wanted, it contains the webserver, the needed API and a browser to preview and test it on my own machine without needing to upload it anywhere.
Unfortunately it still contains at least two major bugs that make it very hard to use: Gadgets with user preferences cannot be tested (setting of preferences will be ignored) and also the built in option to upload it to iGoogle is broken. -- You received this message because you are subscribed to the Google Groups "iGoogle Developer Forum" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/Google-Gadgets-API?hl=en.
