AChartEngineライブラリに問題があります。XYSeriesのインスタンスでremove（index）を呼び出すと、nullポインター例外が発生します。シリーズが存在し、クラッシュの直前にセットカウントを表示していることを知っているので、それは奇妙です。
public View addDataView(){
int datasetCount = dataset.getSeriesAt(0).getItemCount();
XYSeries seriesA = dataset.getSeriesAt(0);
XYSeries seriesB = dataset.getSeriesAt(1);
/** Enforce max data points on the displayed chart */
if (datasetCount > maximumDataPoints - 1) {
System.out.println("SizeOfSeries: "+seriesA.getItemCount());
seriesA.remove(0);
seriesB.remove(0);
}
//d.getTime() format: 1357120800000
seriesA.add(new Date().getTime(), 20 + new Random().nextInt() % 100); // PR // TODO
seriesB.add(new Date().getTime(), 20 + new Random().nextInt() % 100); // BO // TODO;
dataset = new XYMultipleSeriesDataset();
dataset.addSeries(seriesA);
dataset.addSeries(seriesB);
autoscroll();
return ChartFactory.getTimeChartView(context, dataset, renderer, "`ss h:mm a");
}
関連するlogcat出力は次のとおりです。
01-04 14:16:31.806: I/System.out(25215): SizeOfSeries: 20
01-04 14:16:31.806: D/AndroidRuntime(25215): Shutting down VM
01-04 14:16:31.806: W/dalvikvm(25215): threadid=1: thread exiting with uncaught exception (group=0x410fa300)
01-04 14:16:31.806: E/AndroidRuntime(25215): FATAL EXCEPTION: main
01-04 14:16:31.806: E/AndroidRuntime(25215): java.lang.NullPointerException
01-04 14:16:31.806: E/AndroidRuntime(25215): at org.achartengine.model.XYSeries.getY(XYSeries.java:169)
01-04 14:16:31.806: E/AndroidRuntime(25215): at org.achartengine.model.XYSeries.initRange(XYSeries.java:83)
01-04 14:16:31.806: E/AndroidRuntime(25215): at org.achartengine.model.XYSeries.remove(XYSeries.java:140)
01-04 14:16:31.806: E/AndroidRuntime(25215): at charts.Chart.addDataView(Chart.java:75)
01-04 14:16:31.806: E/AndroidRuntime(25215): at com.example.pml.PulseRateActivity$ChartThread.onProgressUpdate(PulseRateActivity.java:68)
01-04 14:16:31.806: E/AndroidRuntime(25215): at com.example.pml.PulseRateActivity$ChartThread.onProgressUpdate(PulseRateActivity.java:1)
01-04 14:16:31.806: E/AndroidRuntime(25215): at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:647)
01-04 14:16:31.806: E/AndroidRuntime(25215): at android.os.Handler.dispatchMessage(Handler.java:99)
01-04 14:16:31.806: E/AndroidRuntime(25215): at android.os.Looper.loop(Looper.java:137)
01-04 14:16:31.806: E/AndroidRuntime(25215): at android.app.ActivityThread.main(ActivityThread.java:4898)
01-04 14:16:31.806: E/AndroidRuntime(25215): at java.lang.reflect.Method.invokeNative(Native Method)
01-04 14:16:31.806: E/AndroidRuntime(25215): at java.lang.reflect.Method.invoke(Method.java:511)
01-04 14:16:31.806: E/AndroidRuntime(25215): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1006)
01-04 14:16:31.806: E/AndroidRuntime(25215): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:773)
01-04 14:16:31.806: E/AndroidRuntime(25215): at dalvik.system.NativeStart.main(Native Method)