dingjikerbo/android-bluetoothkit

Android-BluetoothKit is a Java library for Android apps that need to communicate with Bluetooth Low Energy (BLE) devices. BLE is the variant of Bluetooth used by fitness trackers, smart home sensors, beacons, and similar low-power hardware. The Android Bluetooth API is known for compatibility quirks across different manufacturers and OS versions, this library wraps it to provide a simpler, more consistent interface. The main entry point is a BluetoothClient object, which the README suggests creating as a single global instance. Through it you can scan for nearby devices (mixing BLE and classic Bluetooth scans in a customizable sequence), connect to a device by MAC address with configurable retry counts and timeouts, read and write Characteristics and Descriptors (the data endpoints exposed by BLE devices), subscribe to Notify and Indicate callbacks so the device can push data to the app, and disconnect. All operations use callback interfaces rather than blocking the calling thread. Internally, the library serializes Bluetooth operations into a task queue so they do not conflict with one another. It manages a connection pool to prevent handle leaks and will automatically disconnect the least recently active device when the pool fills. It also supports multi-process app architectures and allows intercepting calls to the underlying Android Bluetooth APIs. The library includes a Beacon parser for reading the advertisement data that BLE devices broadcast without requiring a full connection. You create a Beacon object from the raw scan record and then use BeaconParser to extract fields byte by byte according to the device-specific protocol. Installation is a single Gradle dependency line. The app also needs Bluetooth, Bluetooth Admin, and Location permissions declared in the Android manifest, along with a registered background service included with the library.