private void refreshChart() {
   // TODO Auto-generated method stub
   Float lightNum = collection.getLight();
   int index = mDataCache.addLightData(lightNum);
   if (index == 1) {
     mCurrentSeries.clear();
   }
   mCurrentSeries.add(index, lightNum);
   mChartView.repaint();
 }
  @Override
  public void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    mDataCache = DataCache.getInstance();

    mDataset = new XYMultipleSeriesDataset();
    mRenderer = new XYMultipleSeriesRenderer();
    // Renderer
    // Basic
    mRenderer.setMargins(new int[] {100, 150, 30, 100});
    mRenderer.setChartTitleTextSize(20);
    mRenderer.setApplyBackgroundColor(true);
    mRenderer.setBackgroundColor(0xffE8E8E7);
    mRenderer.setMarginsColor(0xffE8E8E7);
    mRenderer.setLegendTextSize(15);
    mRenderer.setPointSize(5);
    mRenderer.setShowLegend(true);
    mRenderer.setClickEnabled(false);
    // Axes
    mRenderer.setAxisTitleTextSize(50);
    mRenderer.setBarSpacing(50);
    mRenderer.setYTitle("Light");
    // mRenderer.setAxesColor(Color.BLACK);
    // Labels
    // mRenderer.setLabelsColor(Color.WHITE);
    mRenderer.setLabelsTextSize(35);
    mRenderer.setXLabels(0);
    mRenderer.setYLabels(10);
    mRenderer.setYAxisMin(0);
    mRenderer.setYAxisMax(1000);
    mRenderer.setXLabelsColor(Color.BLACK);
    mRenderer.setYLabelsColor(0, Color.BLACK);
    mRenderer.setXLabelsAngle(-45f);
    mRenderer.setXLabelsAlign(Align.CENTER);
    mRenderer.setYLabelsAlign(Align.RIGHT);

    mRenderer.setPanEnabled(false, false);
    mRenderer.setZoomEnabled(false, false);
  }