title: Could an Android app or service sit between the Android APIs that require permissions, and other apps using those APIs/permissions?
body: <p>I'm a hobby programmer and recently an Android device owner, but I have little knowledge about programming Android software.</p>
  
  <p>Is it possible to create an Android app that hooks/monitors/mediates the device's functionalities that need permissions as they are used by other apps on the device?</p>
  
  <p>My use case would be to create an app that blocks or alerts when another app tries to use an unreasonable required permission.</p>
  
  <p>Certain default apps on certain Android devices require permissions that don't seem related to their functionality and refuse to run without them being granted. It would be useful to create an app that allows those apps to be used safely without them being able to abuse those unwarranted permissions.</p>
  
  <p>Similarly, such apps could be used to help find apps which do nefarious things, to help find which features of apps actually do have legitimate but unexpected uses for features behind permissions, or perhaps keep track of how often various apps use various features.</p>
  
  <p>I've tried Googling without find anything about such apps already existing, or features of Android that would make them possible. I've also asked on the Android SE about whether such apps exist without any response so far.</p>