I solved the problem. I don't know why but if you use " mRenderer.setPanEnabled(false,false); " in initialization, you can never re activate panning. So I tried to initialize differently:
XYMultipleSeriesRenderer mRenderer;
GraphicalView graphView;
public GraphicalView getView(Context context) {
... some initialization code ...
mRenderer.setPanEnabled(true, false); //first you should left x-axis pan enabled
graphView = ChartFactory.getTimeChartView(context, dataset, mRenderer,
"HH:mm:ss");
mRenderer.setPanEnabled(false,false); //After you created GraphicalView you can disable pan safely
return graphView;
}
And the code that re enables/disables pan :
public void setFreeStyle(boolean isFree){
if (isFree) {
mRenderer.setPanEnabled(true, true);
graphView.repaint();
}else {
mRenderer.setPanEnabled(false,false);
graphView.repaint();
}
}