YACO - Important System Infos always visible

Ever missed some important date while watching a video? Battery down? Connection bad or lost? Expensive Roaming?!  Too much download?

That's what these "overlay" apps are for: to display some information all the time, not caring whether the app "below" is a fullscreen app or not. Of course it may overlap other data on the screen, that is why it is very flexible about what data to show, how abbreviated, omitting unnecessary units (don't tell that your physics teacher...), and a quick-hide feature. 

"YACO" comes from "Yet another [Clock] Overlay" - I put "clock" in brackets, as it started with a clock, but now it grew to an app showing a whole bunch of information! What could the YACO acronym now stand for? I have no idea.

The app is free and was developed for fun and learning.

Displayable items:

✓ time with and without seconds, date and weekday

✓ battery state, approximate remaining charge/discharge time

✓ GPS data available with speed, height, climb/sink rate and count of satellites, coordinates. Fun to watch in a plane. 

✓ there's also the connection state:
Wifi: SSID, speed, frequency, IPV4 address,  up-/download indicator, daily or monthly data volume, current up-/download rate
Mobile: connection type, roaming warning, provider, signal strength, up-/download indicator, daily or monthly data volume, up-/download rate
inactive Mobile (DualSIM): signal strength, to be able to see the connection strength of the inactive SIM

AAAAND as just mentioned DualSIM support (>= Android 5.1): information about the voice SIM: carrier, signal strength, roaming warning

It is Android 6 permission restrictions aware, so when you get an Android error "Screen Overlay Detected", or if you are not able to grant a permission by touching the button in the dialog where you shall grant it, it is easy to temporarily disable YACO for 5 minutes using its notification entry's "pause" button. It will automatically re-appear after that time. Simple and effective.

This inconvenience can even be circumvented if you allow YACO to be an "accessibility app" (using a shortcut link inside the app's "Info" page makes it easy). Then it can watch out for the permission dialog and disable itself until it's safe to show up again. This way you have an overlay that does not intervene with the permission popup. Yet you must trust me that I don't use the behaviour checks for anything except the hide and show for that sole purpose (BTW: I do promise I don't!). 

If your device has a proximity sensor, covering it can hide YACO so that the items below are uncovered. 

I'd like to have feedback (can be done in the app). This is very important for me.

More information is given at the app's homepage, https://android.chk.digital/yaco/. This app lives and grows and improves using your feedback. 

Permissions:
- GPS - well, for GPS data
- Access Phone State, Network state, Coarse location data: for the information about the data connection, the Android APIs I use need these.

This app uses Accessibility Services. Well- only if you choose to use the Auto-Hide feature! It is not necessary.