achartengine: duplicated chart after resume

Question

I am facing with a werid problem. The demos run well, but in my own app, If I switched to another app, and then switched back, there would be an small duplicated chart on the left bottom.

The chart in my app will be updated(add new (x,y) and repaint) at intervals.

Attached are the original image and image after switched back.

I suspect there are some problems with my onResume() method.

@Override
protected void onResume() {
    super.onResume();

    if (mChartView == null) {
        LinearLayout layout = (LinearLayout) findViewById(R.id.linearlayout_chart);
        mChartView = ChartFactory.getLineChartView(this, mDataSet, mRenderer);
        mRenderer.setClickEnabled(true);
        mRenderer.setSelectableBuffer(100);


        mChartView.setOnClickListener(new OnClickListener() {
            public void onClick(View v) {

            }
        });
        mChartView.setOnLongClickListener(new OnLongClickListener() {
             public boolean onLongClick(View v) {
                 return false;
             }
         });
         mChartView.addZoomListener(new ZoomListener() {

             public void zoomApplied(ZoomEvent e) {
             }
             public void zoomReset() {
             }
         }, true, true);

         mChartView.addPanListener(new PanListener() {
             public void panApplied() {}
         });

         layout.addView(mChartView, new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));
    }

    mChartView.repaint();

}

I cannot figure out why did this happen, does anyone have the same problem?

The normal chart:

After switched back from another app:

Android 3.2 (API Level 13) AChartEngine version 0.7.0 Asus EEE pad

Answer 1

If you are just adding new data, you should just fill dataset with new data and repaint the graph. You create graph onCreate and just refresh it when you add new data.

look at: creating timechar.

Code for refresh - for example in link should be:

private void updateData(List<Point> data) {
        int size= data.size();
        int lastsize = time_series.getItemCount();
        if (lastsize < size) {
        //add new data
        for (int i = lastsize ; i < size; i++) {
            try {
                Point p = pointslist.get(i);
                series.add(p.x,p.y);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }

        mChartView.repaint();
    }
    }

Here you add only new points from your list. I had value object here called Point:

public class Point {
       public Date x;
       public double y;

       public Point() {
         super();
       };
}

You can use your own object or just 2D array.

Hope it helps, Toni