protected override async Task ScanAsync(CancellationToken cancellationToken)
{
// start a scan if bluetooth is present and enabled
if (BluetoothAdapter.DefaultAdapter?.IsEnabled ?? false)
{
try
{
ScanFilter scanFilter = new ScanFilter.Builder()
.SetServiceUuid(new ParcelUuid(_deviceIdService.Uuid))
.Build();
List <ScanFilter> scanFilters = new List <ScanFilter>(new[] { scanFilter });
ScanSettings.Builder scanSettingsBuilder = new ScanSettings.Builder()
.SetScanMode(global::Android.Bluetooth.LE.ScanMode.Balanced);
// return batched scan results periodically if supported on the BLE chip
if (BluetoothAdapter.DefaultAdapter.IsOffloadedScanBatchingSupported)
{
scanSettingsBuilder.SetReportDelay((long)(ScanDurationMS / 2.0));
}
// start a fresh manager delegate to collect/read results
_bluetoothScannerCallback = new AndroidBluetoothClientScannerCallback(_deviceIdService, _deviceIdCharacteristic, this);
BluetoothAdapter.DefaultAdapter.BluetoothLeScanner.StartScan(scanFilters, scanSettingsBuilder.Build(), _bluetoothScannerCallback);
TaskCompletionSource <bool> scanCompletionSource = new TaskCompletionSource <bool>();
cancellationToken.Register(() =>
{
try
{
BluetoothAdapter.DefaultAdapter.BluetoothLeScanner.StopScan(_bluetoothScannerCallback);
}
catch (Exception ex)
{
SensusServiceHelper.Get().Logger.Log("Exception while stopping scan: " + ex.Message, LoggingLevel.Normal, GetType());
}
finally
{
scanCompletionSource.TrySetResult(true);
}
});
await scanCompletionSource.Task;
}
catch (Exception ex)
{
SensusServiceHelper.Get().Logger.Log("Exception while scanning: " + ex.Message, LoggingLevel.Normal, GetType());
}
}
}