Here is a simple application that displays the current value of the ultraviolet index. This accurate measuring tool (portrait orientation, Android 5 or newer) works on the tablets, phones and smartphones that are connected to the Internet. At first, it gets the local coordinates (latitude and longitude) from your device's GPS and then retrieves the UV index from an Internet server. The value of this index is given according to the international standard and represents the strength of the sunburn-producing ultraviolet radiation at your location (its intensity at solar noon).
-- instant display of the UV index for your current location
-- free application - no ads, no limitations
-- only one permission is required (Location)
-- this app keeps the phone's screen ON
-- the color of the Sun's surface follows the UV index