Misfit Shine
I'm thinking of buying the garmin vivosmart but i'm not sure if it is supported by the G2

is there any "smartwear" for taking notifications and display time/day (as small as possible) and it doesn't need to recharge it every night?
I'm using a Misfit Shine with my LG G2. They are coming out with a "cheaper" model soon, the Misfit Flash, but this will only be about the Shine. As for the website
http://www.misfit.com/, so you can check it out. The only thing it doesn't do that you asked about is tracking notifications.
As far as being an activity tracker, it does a pretty good job. There where (don't know if still is) two version of the shine, and it is what it comes with. The version I got came with the magnetic clip and the sports band. The little cheaper model comes with just the magnetic clip. Like most of the trackers, this one is waterproof. Rating for it is 50 meters. So no worries about jumping into the pool with this one and taking a swim.
The major thing about this tacker is that I got mine in April, I just changed the battery a week ago. So it ran for roughly 3-4 months with no charging. But that is the bad part as well, it takes a watch battery. At least the battery is one of the most common ones, and pretty cheap on Amazon. So with this one I was able to get a decent period of time out of it without having to worry about putting it on the charger.
It can tell the time, but does so in a digital/analog way. It shows you where Noon is on it, then shows you the hand, then blinks the minute had for how many minutes past the 5 minute intervals. This is all by the 12 leds on it. To get it to show the time you tap the device two or three times (depending upon settings). This is where the Misfit Flash might be better, as it has a full face button instead of using the accelerometer.
The main negative to this Misfit Shine is that the Android software is a couple of revisions behind ios. It is still useable and will do everything, just annoying seeing a new feature mentioned and seeing that it is only on the ios at this time. Also the software is simple, but they have finally open the API to allow other programs to nab the data. So you might check to see if your preferred health/tracking app has access to it.
Overall I've been quite happy with it. It has survived two trips though the washer, pretty sure it can easily survive more since it is metal. The new Misfit Flash (plastic encloser) might not like the spin cycle as much though.
Hope my little review helps you out some.
Niscandia
PS: I've used it on Cloudy's roms, First on
CloudyFlex and now on
CloudyG3. I did not try it upon a stock rom.