public ScanEventSource()
{
ScanResults = Observable.FromEvent<ScanResult>(h => OnDeviceDetected += h, h => OnDeviceDetected -= h);
var appContext = Application.Context;
var builder = new ScanSettings.Builder();
builder.SetReportDelay(0);
builder.SetScanMode(ScanMode.LowLatency);
var manager = (BluetoothManager)appContext.GetSystemService(Context.BluetoothService);
var adapter = manager.Adapter;
bluetoothLeScanner = adapter.BluetoothLeScanner;
var simpleScanCallback = new SimpleScanCallback(result =>
{
var payload = result.ScanRecord.GetBytes();
var majorId = payload[26];
if (payload[5] == 76 && majorId == Constants.MajorId)
{
var txPower = 255 - payload[29];
var minorId = (payload[27] << 8) + payload[28];
var deviceId = new DeviceIdentifier(new Guid(), majorId, minorId);
var data = new ScanResult(deviceId, result.Rssi, txPower);
OnDeviceDetected?.Invoke(data);
}
});
// taken from https://www.pubnub.com/blog/2015-04-15-build-android-beacon-ibeacon-detector/ , but not detecting our beacons
//bluetoothLeScanner.StartScan(new List<ScanFilter> {CreateScanFilter()}, CreateScanSettings(), simpleScanCallback);
bluetoothLeScanner.StartScan(simpleScanCallback);
}
private ScanSettings CreateScanSettings()
{
ScanSettings.Builder mBuilder = new ScanSettings.Builder();
mBuilder.SetReportDelay(0);
mBuilder.SetScanMode(ScanMode.LowPower);
return mBuilder.Build();
}
private async void StartLeScan(Guid[] serviceUuids)
{
if (_isScanning)
{
Mvx.Trace("Adapter: Already scanning.");
return;
}
_isScanning = true;
// clear out the list
_discoveredDevices = new List<IDevice>();
if (serviceUuids == null || !serviceUuids.Any())
{
if (Build.VERSION.SdkInt < BuildVersionCodes.Lollipop)
{
Mvx.Trace("Adapter < 21: Starting a scan for devices.");
//without filter
_adapter.StartLeScan(this);
}
else
{
Mvx.Trace("Adapter >= 21: Starting a scan for devices.");
if (_adapter.BluetoothLeScanner != null)
{
_adapter.BluetoothLeScanner.StartScan(_api21ScanCallback);
}
else
{
Mvx.Trace("Adapter >= 21: Scan failed. Bluetooth is probably off");
}
}
}
else
{
if (Build.VERSION.SdkInt < BuildVersionCodes.Lollipop)
{
var uuids = serviceUuids.Select(u => UUID.FromString(u.ToString())).ToArray();
Mvx.Trace("Adapter < 21: Starting a scan for devices.");
_adapter.StartLeScan(uuids, this);
}
else
{
Mvx.Trace("Adapter >=21: Starting a scan for devices with service ID {0}.", serviceUuids.First());
var scanFilters = new List<ScanFilter>();
foreach (var serviceUuid in serviceUuids)
{
var sfb = new ScanFilter.Builder();
sfb.SetServiceUuid(ParcelUuid.FromString(serviceUuid.ToString()));
scanFilters.Add(sfb.Build());
}
var ssb = new ScanSettings.Builder();
//ssb.SetCallbackType(ScanCallbackType.AllMatches);
if (_adapter.BluetoothLeScanner != null)
{
_adapter.BluetoothLeScanner.StartScan(scanFilters, ssb.Build(), _api21ScanCallback);
}
else
{
Mvx.Trace("Adapter >= 21: Scan failed. Bluetooth is probably off");
}
}
}
// in ScanTimeout seconds, stop the scan
_cancellationTokenSource = new CancellationTokenSource();
try
{
await Task.Delay(ScanTimeout, _cancellationTokenSource.Token);
Mvx.Trace("Adapter: Scan timeout has elapsed.");
StopScan();
TryDisposeToken();
_isScanning = false;
//important for this to be caled after _isScanning = false;
ScanTimeoutElapsed(this, new EventArgs());
}
catch (TaskCanceledException)
{
Mvx.Trace("Adapter: Scan was cancelled.");
StopScan();
TryDisposeToken();
_isScanning = false;
}
}
