http://code.google.com/apis/gears/tutorial.html
This tutorial does not work offline in the Android emulator. The gears version on the emulator is 0.5.7.0. It doesn't work on a real G1 either, thought the setup is slightly different: I visit the gears site via wifi on a local network server, then I turn off wifi and try again. The site is unreachable and gears does not kick on. Anything special that needs to be done to make things work on G1 phone?
