// OnCreate, called once to initialize the activity.
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    messages = (TextView) findViewById(R.id.messages);
    adapter = BluetoothAdapter.getDefaultAdapter();
    if (adapter == null) {
      // Device does not support Bluetooth
    }

    if (!adapter.isEnabled()) {
      Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
      startActivityForResult(enableBtIntent, 1);
    }

    connectButton = (Button) findViewById(R.id.connectButton);
    connectButton.setVisibility(View.INVISIBLE);
    // connectButton.setBackgroundColor(0xffffff00);
    // connectButton.setText("Start Scanning");
    beginScan();
    animatedCircleLoadingView = (AnimatedCircleLoadingView) findViewById(R.id.circle_loading_view);
    animatedCircleLoadingView.startIndeterminate();

    //        connectButton.setOnClickListener(new View.OnClickListener() {
    //            public void onClick(View v) {
    //
    //                beginScan();
    //
    //            }
    //        });

  }
        // Called when a remote characteristic changes (like the RX characteristic).
        @Override
        public void onCharacteristicChanged(
            BluetoothGatt gatt, BluetoothGattCharacteristic characteristic) {

          super.onCharacteristicChanged(gatt, characteristic);
          vitaminValue = characteristic.getStringValue(0);

          Intent intent = new Intent(MainActivity.this, ResultsActivity.class);
          intent.putExtra(EXTRA_MESSAGE, vitaminValue);
          startActivity(intent);

          animatedCircleLoadingView.stopOk();

          presentValue();
        }