Edit note: Apologies as I did not see the android specific part of your question.
For campaign management unfortunately there is no catch all tool as of yet. Not even one for purchase. However you can make due through multiple tools as I did before I upgraded to a PC tool.
My first suggestion is of course a standard HP/initiative tracker for combat. There are a varied plethora of options ranging from simple HP to HP and effects buffs etc.
So many in fact that covering them all will take all night to write.
For detailed location,rule, NPC, PC and more information I suggest this relatively new app.
The game master companion pro is not system specific. Use it as a tool to note everything from monsters and items to people and places. Even story events. Information can be referenced via links to other templates you’ve created inside the app for faster cross referencing.
The app is new and does have one bug. It doesn’t close previously open pages unless you back out of said page so after being 4-5 pages in depending on your phone it may freeze and crash. You do not lose any saved information thankfully but it can get annoying.
If as I did you decide to upgrade to a PC based management system I suggest all go with what I’ve gotten as option 1.
Realm works from a DM standpoint is leagues above everything else in terms of full campaign record keeping.
However this doesn’t exactly record xp and the like but managing connections and information and plot points is right up its ally.
Control what your players see by marking lines as player known so they can see it in player view.
Besides this I think the best option would be an excel sheet you create yourself.
There’s nothing wrong with wanting all the information at your fingertips in an easy to review format. Not just for keeping track of your players info but also for recording and tracking your own info as well including npc
The company also released a hero lab program for creating characters. This program can be referenced via realm works and also includes useful gmtools for use during gameplay.
Free option would be pcgen.
While unable to manage full campaign info PC gen is a definitive character creation program with multiple game rulesets and the ability to make your own after learning programming.
It has gm tools available inside for HP init and other combat based tracking. And you can build and reference each persons character sheet.