I have an webapp running on the MC-3300 that uses the scanner options connected via the datawedge.
On one of the scanners I can not scan anymore. When scanning no data will show up on the screen.
Also the android navigationbar at the top will not show while swiping.
When I tried scanning in the DWDemo app, nothing happens.
If the DWDemo app is not working then it's probably something more fundamental than scanning with a webapp. Presume you have checked all the obvious steps like rebooting the device - also check that DataWedge is still enabled. You can also turn on DW logging and investigate logcat to see if any errors are being logged there.