title: How to combine a multiple series bar chart and a line chart
body: <p>I'd like to combine a bar chart with 2 data series and a line chart in AChartEngine but I was not able to do that. In  the AChartEngine demo I found only an example which combines a single series bar chart and a line Chart (Combined temperature).</p>
  
  <p>What I'd like:
  <a href="http://i.imgur.com/Jxq0BTV.jpg" rel="nofollow">http://i.imgur.com/Jxq0BTV.jpg</a></p>
  
  <p>If I define 3 series (2 for bar chart, 1 for line chart) in a dataset for a combined XY chart like this:
  <code>ChartFactory.getCombinedXYChartView(ctx, dataset, renderer, new String[] { BarChart.TYPE, BarChart.TYPE, LineChart.TYPE });</code></p>
  
  <p>...then I get this result:
  <a href="http://i.imgur.com/71HAPo3.jpg" rel="nofollow">http://i.imgur.com/71HAPo3.jpg</a></p>
  
  <p>If I define 3 series and 2 chart types:<br>
  <code>ChartFactory.getCombinedXYChartView(ctx, dataset, renderer, new String[] { BarChart.TYPE, LineChart.TYPE });</code></p>
  
  <p>...then I get an exception:<br>
  <code>java.lang.IllegalArgumentException: Dataset, renderer and types should be not null and the datasets series count should be equal to the types length<br>
  at org.achartengine.ChartFactory.getCombinedXYChartView(ChartFactory.java:202)</code></p>
  
  <p>Do I misunderstand something or does AChartEngine simply not support a multiple series bar chart and a line chart in combination?</p>