Android-Bluetooth-Low-Energy-Wrapper-BLE

This sample project demostrate how an Android app communicate with a Bluetooth Low Energy Device.

Purpose of BLE Wrapper

While integrating the BLE device with Android app, the overall documentation was clustering the code. So, it was felt that it would be better to create a callback mechanism wherein we just set up the BLE device with a single object. Because its a wrapper, it mainly follows the google documentation and has some added scenarios over it.

What it simplifies

BluetoothManager is the object that the app deals with. It helps in handling the following

• handles the permission for Android device running both above and below Marshmallow
• detects the device bluetooth state (ON/OFF)
• automatically saves the last connected device and we can retrieve it anytime as

Device lastDevice = new Device(context);
Log.d("last connected device", String.format("name: %s, "address: %s", lastDevice.getDeviceName(), lastDevice.getDeviceAddress()));

• a clean pop for scan devices and connect to the selected device.
• creates a session for a connected device and destroy it when not in use or not communicating.
• returns a list of paired devices
• returns if a device is connected or not.

Easy set up

Create an instance of BluetoothManager object and get started as

bluetoothManager = new BluetoothController(this);
bluetoothManager.setGoogleApiClient(mGoogleApiClient);

/* must call onActivityResult for bluetoothManager object to set the required results */
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
   super.onActivityResult(requestCode, resultCode, data);
   bluetoothManager.onActivityResult(requestCode, resultCode, data);
}

Callbacks provided

The wrapper provides callbacks for managing the various actions to get running with a BLE device.

Permission Callbacks: Set this to observe any state related to bluetooth permission, location permission(for device > M), device bluetooth state and do we need to ask for permission, set the ConnectionCallback as

bluetoothManager.setConnectionCallbacks(this);

@Override
public void askLocationPermission() {}

@Override
public void gpsState(int connectionState) {}

@Override
public void bleConnectionState(int connectionState) {}

@Override
public void permissionState(int permissionState) {}

@Override
public void bleDeviceConnectionState(int deviceConnectionState) {}

Communication Callback: For to receive data in your parent Activity/Fragment, set

bluetoothManager.setDataCallbacks(this);

@Override
public void onDataReceived(String data) {
  log("Data received: "+ data);
}

Discovery Callback: Mainly used in ScanDeviceFragment, can be used to find BLE devices and connect to them.

bluetoothManager.setDiscoveryCallbacks(this);

@Override
public void onDeviceDiscovered(BluetoothDevice device) {}

@Override
public void onDeviceDiscoveryStopped() {}

ConnectedDevice Callbacks: Set this callback to know if device is connected or disconnected during runtime

bluetoothManager.setConnectedDeviceStateCallbacks(this);

@Override
public void connectedDeviceState(int connectedDeviceState) {}

Optional feature

Bluetooth State Detection: Set this to know bluetooth on device is turned ON or OFF at runtime. This is a broadcast receiver with defined codes and must be unregistered in onPause().

@Override
protected void onResume() {
  super.onResume();
  bluetoothManager.registerStateDetection();
}

Scan Device Fragment A fragment which is just required to be called and it'll handle the scan itself. It mainly scans for 10 seconds and then it stops scanning but we can rescan.

ScanDeviceFragment scanDeviceFragment = new ScanDeviceFragment();
scanDeviceFragment.setScanDeviceListener(new ScanDeviceFragment.ScanDeviceListener() {
    @Override
    public void onDeviceSelected(BluetoothDevice device) {
        /* once a device is connected, we can connect to it and stop scanning */
    });
scanDeviceFragment.show(getFragmentManager(), "ScanDeviceFragment");