android-bluetooth-expert

Android Bluetooth permissions require different approaches before and after API 31. You must request legacy location permissions for older API levels while using the newer Bluetooth permissions introduced in API 31 and above to ensure proper scanning and connectivity.

Android BLE GATT status code 133 typically indicates a connection failure caused by overlapping GATT operations or improper connection management. Serializing GATT operations through a queue and using a bound-service pattern helps diagnose and resolve this error.

Companion Device Manager (CDM) pairs Bluetooth devices without location permissions by using API 26+ specific pairing flows. It handles API level differences automatically, allowing you to bypass standard location permission requirements for BLE and Classic devices.

The best way to structure an Android BLE service is using a bound-service pattern. This approach serializes GATT operations through a queue, preventing concurrent operation failures and ensuring robust data transfer and connection management.

Android BLE supports LE Audio routing across API levels 21 through 34 with specific implementation differences. You must apply API-specific coding practices to handle audio routing correctly while maintaining secure and safe connections.

To exchange data with Bluetooth Classic devices using RFCOMM, initialize Bluetooth, request proper permissions, scan for devices, and establish an SPP connection. This allows bidirectional data transfer streams distinct from BLE GATT operations.