How to share data locally between apps in Android?

Question

Java

Good day to all.
There are several applications on unity3d for android.
I would like to save some parameters in offline mode in the first application and access them from the second application. Without opening the second application at the time of transfer.
I see three options

• external storage
  
• Google Play Service
  
• exchange via server
  

storage is not suitable, because most players do not want to give access to it
GPS is also disgustingly implemented.
Permanent online is not our forte, so the third option is also not an option.
in IOS there is a keychain that allows you to exchange data within applications of one developer. In a droid, keychain has a slightly different meaning.
Android Guru, are there any other ways?

Answer 1

If we are talking about applications on one device, then:
- Content provider
- Broadcast receiver
On different devices - only through the server