Meshtastic-Android/core/ble/README.md
James Rich 875cf1cff2
refactor: migrate from Hilt to Koin and expand KMP common modules (#4746)
Signed-off-by: James Rich <2199651+jamesarich@users.noreply.github.com>
2026-03-10 01:19:46 +00:00

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Markdown

# `:core:ble`
## Module dependency graph
<!--region graph-->
```mermaid
graph TB
:core:ble[ble]:::kmp-library
classDef android-application fill:#CAFFBF,stroke:#000,stroke-width:2px,color:#000;
classDef android-application-compose fill:#CAFFBF,stroke:#000,stroke-width:2px,color:#000;
classDef android-feature fill:#FFD6A5,stroke:#000,stroke-width:2px,color:#000;
classDef android-library fill:#9BF6FF,stroke:#000,stroke-width:2px,color:#000;
classDef android-library-compose fill:#9BF6FF,stroke:#000,stroke-width:2px,color:#000;
classDef android-test fill:#A0C4FF,stroke:#000,stroke-width:2px,color:#000;
classDef jvm-library fill:#BDB2FF,stroke:#000,stroke-width:2px,color:#000;
classDef kmp-library fill:#FFC1CC,stroke:#000,stroke-width:2px,color:#000;
classDef unknown fill:#FFADAD,stroke:#000,stroke-width:2px,color:#000;
```
<!--endregion-->
## Overview
The `:core:ble` module contains the foundation for Bluetooth Low Energy (BLE) communication in the Meshtastic Android app. It has been modernized to use **Nordic Semiconductor's Android Common Libraries** and **Kotlin BLE Library**.
This modernization replaces legacy callback-based implementations with robust, Coroutine-based architecture, ensuring better stability, maintainability, and standard compliance.
## Key Components
### 1. `BleConnection`
A robust wrapper around Nordic's `Peripheral` and `CentralManager` that simplifies the connection lifecycle and service discovery using modern Coroutine APIs.
- **Features:**
- **Connection & Await:** Provides suspend functions to connect and wait for a terminal state (Connected or Disconnected).
- **Unified Profile Helper:** A `profile` function that manages service discovery, characteristic setup, and lifecycle in a single block, with automatic timeout and error handling.
- **Observability:** Exposes `peripheralFlow` and `connectionState` as Flows for reactive UI and service updates.
- **Connection Management:** Handles PHY updates, MTU logging, and connection priority requests automatically.
### 2. `BluetoothRepository`
A Singleton repository responsible for the global state of Bluetooth on the Android device.
- **Features:**
- **State Management:** Exposes a `StateFlow<BluetoothState>` reflecting whether Bluetooth is enabled, permissions are granted, and which devices are bonded.
- **Permission Handling:** Centralizes logic for checking Bluetooth and Location permissions across different Android versions.
- **Bonding:** Simplifies the process of creating bonds with peripherals.
### 3. `BleScanner`
A wrapper around Nordic's `CentralManager` scanning capabilities to provide a consistent and easy-to-use API for BLE scanning with built-in peripheral deduplication.
### 4. `BleRetry`
A utility for executing BLE operations with retry logic, essential for handling the inherent unreliability of wireless communication.
## Integration in `app`
The `:core:ble` module is used by `NordicBleInterface` in the main application module to implement the `IRadioInterface` for Bluetooth devices.
## Usage
Dependencies are managed via the version catalog (`libs.versions.toml`).
```toml
[versions]
nordic-ble = "2.0.0-alpha15"
nordic-common = "2.8.2"
[libraries]
nordic-client-android = { module = "no.nordicsemi.kotlin.ble:client-android", version.ref = "nordic-ble" }
# ... other nordic dependencies
```
## Architecture
The module follows a clean architecture approach:
- **Repository Pattern:** `BluetoothRepository` mediates data access.
- **Coroutines & Flow:** All asynchronous operations use Kotlin Coroutines and Flows.
- **Dependency Injection:** Koin is used for dependency injection.
## Testing
The module includes unit tests for key components, mocking the underlying Nordic libraries to ensure logic correctness without requiring a physical device.