android - Data from accelerometer to achartengine in realtime -

i'm new android , still playing it. however, ran problem , got stuck. i'm trying take data accelerometer , plot using achartengine in real time. found tutorial first saves data accelerometer , plots it. though can run on emulator, once deploy on nexus 4 running jelly bean, application crashes. can't seem figure out why. have suggestions?

public class mainactivity extends activity implements sensoreventlistener,onclicklistener {  private button butstart, butstop; private linearlayout layout; private boolean started = false; private sensormanager sensormanager;   private static graphicalview view; private linechart line = new linechart(); private long t;  @override protected void oncreate(bundle savedinstancestate) {     super.oncreate(savedinstancestate);     setcontentview(r.layout.activity_main);       layout = (linearlayout) findviewbyid(r.id.chart_container);     sensormanager = (sensormanager) getsystemservice(context.sensor_service);     new arraylist<accelemoterdata>();       butstart = (button) findviewbyid(r.id.butstart);     butstop = (button) findviewbyid(r.id.butstop);      butstart.setonclicklistener(this);     butstop.setonclicklistener(this);      butstart.setenabled(true);     butstop.setenabled(false);  }  @override public boolean oncreateoptionsmenu(menu menu) {     getmenuinflater().inflate(r.menu.main, menu);     return true; } @override public void onaccuracychanged(sensor sensor, int accuracy) {     // todo auto-generated method stub  }  @override public void onsensorchanged(sensorevent event) {     if (started) {          double x = event.values[0];         double y = event.values[1];         double z = event.values[2];         long time = system.currenttimemillis();         accelemoterdata data = new accelemoterdata(time, x, y, z);          line.addnewdata(data, t);         view.repaint();         } }  @override public void onclick(view v) {     switch (v.getid()) {     case r.id.butstart:          view = line.getview(this);         setcontentview(view);         butstop.setenabled(true);         butstart.setenabled(false);         new arraylist<accelemoterdata>();         started = true;         t = system.currenttimemillis();         sensor accelerometer = sensormanager.getdefaultsensor(sensor.type_accelerometer);         sensormanager.registerlistener(this, accelerometer,sensormanager.sensor_delay_fastest);           break;     case r.id.butstop:         butstop.setenabled(false);         butstart.setenabled(true);         started = false;         sensormanager.unregisterlistener(this);         layout.removeallviews();          break;     default:         break;      }     } 

}

public class linechart {  private graphicalview view;    private timeseries xseries = new timeseries("x"); private timeseries yseries = new timeseries("y"); private timeseries zseries = new timeseries("z");  private xymultipleseriesdataset dataset = new xymultipleseriesdataset();  xyseriesrenderer xrenderer = new xyseriesrenderer(); xyseriesrenderer yrenderer = new xyseriesrenderer(); xyseriesrenderer zrenderer = new xyseriesrenderer();  xymultipleseriesrenderer multirenderer = new xymultipleseriesrenderer();  public linechart() {       dataset.addseries(xseries);     dataset.addseries(yseries);     dataset.addseries(zseries);       xrenderer.setcolor(color.red);     xrenderer.setpointstyle(pointstyle.circle);     xrenderer.setfillpoints(true);     xrenderer.setlinewidth(1);     xrenderer.setdisplaychartvalues(false);       yrenderer.setcolor(color.green);     yrenderer.setpointstyle(pointstyle.circle);     yrenderer.setfillpoints(true);     yrenderer.setlinewidth(1);     yrenderer.setdisplaychartvalues(false);       zrenderer.setcolor(color.blue);     zrenderer.setpointstyle(pointstyle.circle);     zrenderer.setfillpoints(true);     zrenderer.setlinewidth(1);     zrenderer.setdisplaychartvalues(false);       multirenderer.setxlabels(0);     multirenderer.setlabelscolor(color.red);     multirenderer.setcharttitle("t vs (x,y,z)");     multirenderer.setxtitle("sensor data");     multirenderer.setytitle("values of acceleration");     multirenderer.setzoombuttonsvisible(true);      multirenderer.addseriesrenderer(xrenderer);     multirenderer.addseriesrenderer(yrenderer);     multirenderer.addseriesrenderer(zrenderer); }  public graphicalview getview(context context)  {     view =  chartfactory.getlinechartview(context, dataset, multirenderer);     return view; }  public void addnewdata(accelemoterdata data, long t) {     xseries.add(data.gettime()-t, data.getx());     yseries.add(data.gettime()-t, data.gety());     zseries.add(data.gettime()-t, data.getz());  } 

}

of course need class accelerometerdata, copy , paste code , write class accelerometerdata using criteria, , works me. except, changed this:

line.addnewdata(data, time); 

in main activity.

and class accelerometerdata (well in case changed name because spanish), change name accelerometerdata , should work.

    public class datosacelerometro { private long time; private float x; private float y; private float z;  public datosacelerometro(long time, float x, float y,float z) {     this.time=time;     this.x = x;     this.y = y;     this.z = z; }      public long gettime(){            return time;     }  public float getx() {        return x; }  public float gety() {     return y; }  public float getz(){     return z; } 

}

i hope fix unknowing error. ;)