android-bluetooth-ble

name	android-bluetooth-ble
description	Handling Bluetooth Low Energy, flow wrappers, and Android 12+ permissions.
category	hardware-form-factors
risk	high
source	community
date_added	2026-04-07
metadata	{"triggers":["@ble","bluetooth","iot"]}

Android Bluetooth Low Energy (BLE) & Permissions 📡

Working with IoT devices, Gatt Servers, and BLE scanning requires precise lifecycle control and permission handling.

⚡ When to Use

• When connecting to hardware devices via Bluetooth.

🏗️ Core Rules / Pillars

1. The Android 12+ Permission Shift

• Pattern: Location permissions are NO LONGER explicitly required for BLE if you declare that you are not using BLE for location tracking.
• Implementation: Use BLUETOOTH_CONNECT and BLUETOOTH_SCAN permissions in the manifest, and optionally set android:usesPermissionFlags="neverForLocation" on BLUETOOTH_SCAN.

2. Reactive BLE Wrappers

• Pattern: The native BluetoothGattCallback is entirely callback-based and prone to race conditions if used directly.
• Implementation: You MUST wrap BLE reads, writes, and connection states in Kotlin callbackFlow { } or MutableStateFlow to guarantee state correctness across coroutines.

🚧 Critical Anti-Hallucination Guards

• Trap: NEVER fire multiple BLE GATT operations at exactly the same time. The Android BLE stack will drop packets quietly. Always queue GATT operations sequentially!