In CIQ, the general rule is an app can look at system settings but not change them. Consider the case where your app turns off tones, and leaves them off. If the user then runs another app that needs tones, that developer could get bug reports of tones not working when it has nothing to do with their app.
Not sure what you mean about low power mode, as that's something the user can't change in standard system settings either. Do you want to display seconds all the time or something? In that case, look at the new 2.3.x feature of "always active" (1hz) watchfaces on some devices.
The 820 has a battery save mode. It works great, but I would like to be able to easily change it on the fly while riding. I would also like to be able to do this with tones since you have to go through quite a few menus to toggle it.
Not sure how the low power would work if you need to continue recording your ride... maybe some of the techniques could be applied they are doing now, but certainly not all :)
Battery save mode continues to save all ride data. You can specify the types of notifications that you would like to cause the screen to become activated again. For instance, an upcoming turn when using navigation or a garmin radar notification.
I'll repeat what Jim has said above.. ConnectIQ apps/widgets/data fields can look at device settings, but they cannot change them. Period. The functionality you are wanting to add is simply not something you can do from ConnectIQ.
Allowing a CIQ app to change system settings would be a mess in my opinion. Your app could change something expected in my app, without the user themselves changing that setting and knowing about the change. That would surely lead to problems. Double thumbs down on this one.
Travis and I have been doing CIQ for quite a long time, and I can safely say, I've never seen a case were allowing CIQ to change standard settings would make sense. Never.
