MPAndroidChart - In CombinedChart show Line Data and Bar Data on separate Buttons click respectively

0
votes

In MPAndroidChart library I have combined chart which consist of 1 Line data and 1 Bar data. I have 2 buttons lets say on

  • Button 1 click Bar Data should be shown and Line Data should Hide.
  • Button 2 click Line Data should be shown and Bar Data should Hide.

Initially I have loaded the Bar Chart same I have done on Button 1 Click event. What I am doing at the moment is

  • on Button 1 Click I do fllowing :

    CombinedData data = new CombinedData(getXAxisValues()); data.setData(generateBarData()); mChart.setData(data); mChart.invalidate();

  • on Button 2 Click:

    mChart.getData().removeDataSet(mChart.getData().getDataSetByIndex(0)); mChart.getData().notifyDataChanged(); mChart.notifyDataSetChanged() CombinedData data = new CombinedData(getXAxisValues()); data.setData(generateLineData()); mChart.setData(data); mChart.invalidate();

On Button 2 click it gives me following exception

java.lang.NullPointerException: Attempt to invoke virtual method 'void com.github.mikephil.charting.data.LineData.notifyDataChanged()' on a null object reference

I am new with Android programming. Kindly help me in this matter. Thanks in Advance.

1
androidmpandroidchart

1 Answers

0
votes

In on button 2 click you are removing the data from the chart and then trying to retrieve it to call notifyDataSetChanged. The chart is returning null because there is no data.

I would remove this line mChart.getData().notifyDataChanged(); it does nothing. And move mChart.notifyDataSetChanged() to below mChart.setData(data);