Update Line Chart every second

Question

I want to use one of the classes in this example

I'm displaying the line chart

In my case the x-axis represents time so I want to update the chart each second by calling execute function bellow and doing the following: 1-adding more points 2-Moving the Pan to my current time

so in the end I'm expecting to see the lines on the plot moving with time

I tried creating a function called update which create a new thread and calling it from onResume but the application crashes and I get

AndroidRuntime(23861): FATAL EXCEPTION: Thread-11775
AndroidRuntime(23861): android.view.ViewRootImpl$CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views.
AndroidRuntime(23861): android.view.ViewRootImpl$CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views.
AndroidRuntime(23861):  at android.view.ViewRootImpl.checkThread(ViewRootImpl.java:5908)
AndroidRuntime(23861):  at android.view.ViewRootImpl.requestLayout(ViewRootImpl.java:837)
AndroidRuntime(23861):  at android.view.View.requestLayout(View.java:15792)
AndroidRuntime(23861):  at android.widget.RelativeLayout.requestLayout(RelativeLayout.java:358)
AndroidRuntime(23861):  at android.view.ViewGroup.removeAllViews(ViewGroup.java:3902)

here is my main class

public class ChartDemo extends Activity {
    private AverageCubicTemperatureChart TCh = new AverageCubicTemperatureChart();
    RelativeLayout LayoutToDisplayChart;

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        LayoutToDisplayChart=(RelativeLayout)findViewById(R.id.relative_layout1);
    }

  @Override
   protected void onResume() {
    super.onResume();
    Intent achartIntent = TCh.execute(this,LayoutToDisplayChart);
    AverageCubicTemperatureChart.update(this,LayoutToDisplayChart);

    }
 }

The code for the class AverageCubicTemperatureChart

/**
  * Average temperature demo chart.
 */
public class AverageCubicTemperatureChart implements IDemoChart  {
 /**
 * Returns the chart name.
 * 
* @return the chart name
*/
    public String getName() {
        return "Average temperature";
    }

    public static void update(Context c, RelativeLayout p)
    {
       thread = new Thread() {
      public void run() {
          while(true) {
              try {
                  Thread.sleep(1000);
              } catch (InterruptedException e) {
                  e.printStackTrace();
              }

              parent.removeAllViews();
              execute(c,p);

          }
      }
  };
  thread.start();
     }

    /**
    * Returns the chart description.
    * 
    * @return the chart description
    */
    public String getDesc() {
        return "The average temperature in 4 Greek islands (cubic line chart)";
    }

     /**
     * Executes the chart demo.
     * 
     * @param context the context
     * @return the built intent
     */
    public Intent execute(Context context,RelativeLayout parent) {
        String[] titles = new String[] { "Crete", "Corfu", "Thassos", "Skiathos" };
        List<double[]> x = new ArrayList<double[]>();
        for (int i = 0; i < titles.length; i++) {
           x.add(new double[] { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 });
        }
        List<double[]> values = new ArrayList<double[]>();
        values.add(new double[] { 12.3, 12.5, 13.8, 16.8, 20.4, 24.4, 26.4, 26.1, 23.6, 20.3, 17.2,
                                 13.9 });
        values.add(new double[] { 10, 10, 12, 15, 20, 24, 26, 26, 23, 18, 14, 11 });
        values.add(new double[] { 5, 5.3, 8, 12, 17, 22, 24.2, 24, 19, 15, 9, 6 });
        values.add(new double[] { 9, 10, 11, 15, 19, 23, 26, 25, 22, 18, 13, 10 });
        int[] colors = new int[] { Color.BLUE, Color.GREEN, Color.CYAN, Color.YELLOW };
        PointStyle[] styles = new PointStyle[] { PointStyle.CIRCLE, PointStyle.DIAMOND,
                                                PointStyle.TRIANGLE, PointStyle.SQUARE };
        XYMultipleSeriesRenderer renderer = AbstractDemoChart.buildRenderer(colors, styles);
        int length = renderer.getSeriesRendererCount();
        for (int i = 0; i < length; i++) {
             ((XYSeriesRenderer) renderer.getSeriesRendererAt(i)).setFillPoints(true);
        }
        AbstractDemoChart.setChartSettings(renderer, "Average temperature", "Month", "Temperature", 0, 100, 0, 100,
        Color.LTGRAY, Color.LTGRAY);
        renderer.setXLabels(12);
        renderer.setYLabels(10);
        renderer.setShowGrid(true);
        renderer.setXLabelsAlign(Align.RIGHT);
        renderer.setYLabelsAlign(Align.RIGHT);
        renderer.setZoomButtonsVisible(true);
        renderer.setPanLimits(new double[] { 0, 200, 0, 100 });
        renderer.setZoomLimits(new double[] { 0, 200, 0, 100 });
        Intent intent = ChartFactory.getCubicLineChartIntent(context, AbstractDemoChart.buildDataset(titles, x, values),
        renderer, 0.33f, "Average temperature");
        mChartView2=ChartFactory.getCubeLineChartView(context,  AbstractDemoChart.buildDataset(titles, x, values), renderer, 0.33f); 
        parent.addView(mChartView2);
        return intent;
    }
}

Answer 1

You will have to use runOnUiThread()

As i already pointed out here: How to transfer the value of the string from thread to another?

To clarify: Your Logcat error means, that you cannot modify your parent-View in AverageCubicTemperatureChart because this Thread is not the owner of parent.

Changing the line parent.addView(mChartView2) to:

parent.runOnUiThread(new Runnable() {
    @Override
    public void run() {
        parent.addView(mChartView2);
    }
});

should solve your problem