android - aChartEngine; getting SeriesSelection from within onTouchListener -

i'm creating line chart, using xyseries, etc. working great, except i'm finding impossible graphicalview.getcurrentseriesandpoint() within callbacks of ontouchllistener. have both , onclick , ontouch on chart, need handle other gestures data point onclicks.

when use onclicklistener, works expected; calls chartview.getcurrentseries... returns seriesselection. however, once set ontouchelistener, breaks.

i started standard means of mixing two, maintain touch state within ontouchlistener, , when resolves motionevent.action_up, if determine it's click, invoke performclick on passed in view, chart/graphicalview, results in null return getcurrentseriesandpoint call. here's code; nothing special going on here:

case motionevent.action_up:                          if (onclick)                             {                             log.d(tag, "actionup onclick should clicking, " +                                                "and mcurrentss: " + mcurrentseriesselection);                             seriesselection ss = ((graphicalview)v).getcurrentseriesandpoint(); //always null                             if (ss == null)                                 {                                 log.d(tag, "no point clicked");                                 }                             else                                 {                                 log.d(tag, "handle overlays on point: " + ss);                                 mlistener.userdidclickpoint(ss);                                  }                             return true;                             }... 

ss null. tried call on reference have chart/graph...view directly, , still null. next idea making call during ontouch's motionevent.action_down block, , tried both direct call on view, , performclick on view see if grab ss there, this:

case motionevent.action_down:                         onclick = true;                         //mcurrentseriesselection var hang onto results;              ends null                         mcurrentseriesselection = mchart.getcurrentseriesandpoint();                         //this doesn't work either, call in onclick return null                         v.performclick();                         log.d(tag, "the current series selection in ontouch action down: " +                                            mcurrentseriesselection);                         break; 

now thoroughly confused, search more knowledge, , come across wonderful post, involves getting current series, , iterating on each of it's points, comparing view position coordinate (while accounting point size set on renderer, even), wrap on method of own:

private seriesdatapoint seriespointforclickedviewwithmotionevent(view v, motionevent event)         {         seriesdatapoint sdp = null;         seriesselection ss = null;         point screencoordinate = null;         (int = 0; < mseries.getitemcount(); i++)             {             log.d(tag, "mseries.getx i: " + mseries.getx(i));             log.d(tag, "mseries.gety i: " + mseries.gety(i));             double[] xy = mxychart.toscreenpoint(new double[]{mseries.getx(i), mseries.gety(i)}, 0);              double dx = (xy[0] - event.getx());             double dy = (xy[1] - event.gety());             double distance = math.sqrt(dx * dx + dy * dy);             if (distance <= 2 * mrenderer.getpointsize())                 {                 screencoordinate = new point((float) xy[0],                                                     (float) xy[1]);                 ss = mxychart.getseriesandpointforscreencoordinate(screencoordinate);                 sdp = new seriesdatapoint(ss, screencoordinate);                 break;                 }             }         return sdp;         } 

(where seriesdatapoint simple class i'm using pass stuff need caller; ignore it) problem is:

double[] xy = mxychart.toscreenpoint(new double[]{mseries.getx(i), mseries.gety(i)}, 0); 

crashed npe, though mxychart, , mseries , not null , valid. total bummer...

so, i'm out of ideas on how accomplish need do, getting seriesselection corresponding clicked chart point. thanks.

my error thinking referencing same line chart graphical view using, , not. ended redoing way instantiate graphicalview, using (context, abstractchart) constructor, , passing in linechart instance. once done, problem line:

double[] xy = mxychart.toscreenpoint(new double[]{mseries.getx(i), mseries.gety(i)}, 0); 

no longer crashed, , able determine series point clicked within ontouch handling. so, in short, have make sure linechart you're calling method on in fact 1 being rendered part of constructing graphicalview. know that's been mentioned elsewhere, didn't connect @ first, so, reiterating here. thanks.