Today I added camera support to my google glass app.
The application worked like a charm when launched it through the custom launcher but I was surprised by the fact that starting it with the voice command "ok glass" resulted in a "failed to connect to camera service" Runtime Exception.
Surfing the net, I discovered that this is a common issue (take a look at this).
It seems that the delay between the voice recogniser closing event and the camera open event is causing a memory overload.
Someone succeeded in avoiding the problem by pausing the app for a certain time (1000 Milliseconds) before opening the camera.
However this solution didn't work for me, maybe because I'm using XE12. However I found out that if you say "Ok glass" and wait for 2 seconds before you say the app name it works flawlessly.
As this is not a very "professional and scientific" solution I will review this problem in the future, so stay tuned.