WIP: Support API 31 (Android 12) new Bluetooth permissions

[dariuszseweryn]

API 31 introduces new Bluetooth permissions required for BLE operations. In the context of RxAndroidBle the important ones are:

• BLUETOOTH_SCAN — replaces previously needed ACCESS_FINE_LOCATION
• BLUETOOTH_CONNECT — a new concept

Considerations:
The library's AndroidManifest.xml does include ACCESS_COARSE_LOCATION and ACCESS_FINE_LOCATION since API 23. Technically these could be restricted to maxSdkVersion="30" but it could be a breaking change for apps that require location access otherwise. There is a new example in the Readme if the user does not want to require location access for other reasons than scanning BLE peripherals.

TODO:

• Check if having BLUETOOTH_SCAN makes Location Services requirement obsolete
  Result: If the user sets flag neverForLocation then Location Services are not needed. Otherwise they still are needed to get scan results.
• Adjust the code to conform to new requirements for Location Services
• Add check for new BLUETOOTH_CONNECT permission? Expected to be a thrown exception anyway
• Design new RxBleClient#State API for convenient usage with the new permission model Extracted to Create new API for getting state of RxBleClient #764

Resolves #752

[b055man]

Hi @dariuszseweryn,

thanks for working on this!
Is there any ETA for publishing this change? Better yet, any chance for getting a new version of multiplatform_ble_adapter + flutter_ble_lib once that change is merged.. ? :)

[dariuszseweryn]

Hi, I was on long vacations. I am trying to maintain only the RxAndroidBle. Other mentioned libs were transferred to a different entity...