achartengine toScreenPoint(double) always returns nullPointerException

Question

Every time I call this method it return nullpointerexception:

java.lang.NullPointerException at org.achartengine.chart.XYChart.toScreenPoint(XYChart.java:867)

Answer 1

There used to be this bug in an older version of AChartEngine. I suggest you update to 1.1.0.

Also, please note that the chart must have been already displayed when calling the method. If the chart didn't display on screen then there is no way to calculate that.