//callback -> StartActivityForResult
 protected override void OnActivityResult(int requestCode, Result resultCode, Intent data)
 {
     base.OnActivityResult(requestCode, resultCode, data);
     if (resultCode == Result.Ok)
     {
         ble.Scanner();
     }
     else
     {
         flag_connessioneBLE = false;
         Handler mHandler = new Handler();
         mHandler.PostDelayed(new Action(delegate {
             Finish();
         }), 5000);
         Toast.MakeText(this, "BLE Spento!", ToastLength.Short).Show();
     }
 }
        protected override void OnResume()
        {
            base.OnResume();

            ble = new BluetoothScanner(this, this, this);
            ble.ScanResultEvent += Ble_ScanResultEvent;

            mListView            = FindViewById <ListView>(Resource.Id.listView1);
            adapterList          = new DeviceAdapter(this, ble.mLeDevices);
            mListView.Adapter    = adapterList;
            mListView.ItemClick += MListView_ItemClick;

            if (ble.mBluetoothAdapter != null)
            {
                if (!ble.mBluetoothAdapter.IsEnabled)
                {
                    if (flag_connessioneBLE)
                    {
                        Intent enableBtIntent = new Intent(BluetoothAdapter.ActionRequestEnable);
                        StartActivityForResult(enableBtIntent, 2);
                    }
                }
                else
                {
                    ble.Scanner();
                }
            }
            else
            {
                Handler mHandler = new Handler();
                mHandler.PostDelayed(new Action(delegate {
                    Finish();
                }), 2500);
                Toast.MakeText(this, "BLE Not Supported!", ToastLength.Short).Show();
            }
        }