CODEWITHSUNDEEP
androidmpandroidchart
Alexandr Sushkov
Alexandr Sushkov

Reputation: 591

ValueFormatter throws IndexOutOfBoundsException

I have a small problem. I'm trying to make a listView of BarCharts, where xAxis represents categories, and yAxis - cost.

Here is my data. entry

entries.add(new BarEntry(xAxis, cost, categoryName));

xAxis is just a position in chart, I put category name as 3rd parameter. Then I put it in array list of BarData

ArrayList<BarData> months = new ArrayList<>(); 
BarDataSet set = new BarDataSet(entries, monthName);
ArrayList<IBarDataSet> dataSets = new ArrayList<>();
dataSets.add(set);
BarData barData = new BarData(dataSets);
months.add(barData);

Then in adapter I set value formatter 

BarData data = getItem(position);
...
xAxis.setValueFormatter(new MyValueFormatter(data.getDataSetByIndex(0)));

and in MyValueFormatter I'm trying to get category name from entry and set it as xAxis value.

public class MyValueFormatter implements IAxisValueFormatter {

private IBarDataSet mDataSet;

public StatisticByMonthValueFormatter(IBarDataSet data) {
    mDataSet = data;
}

@Override
public String getFormattedValue(float value, AxisBase axis) {
    return (String) mDataSet.getEntryForIndex((int) value).getData();
}
}

This woks, but sometimes when I'm scrolling list view I get

java.lang.IndexOutOfBoundsException: Invalid index 4, size is 2.

I know, that bug in the getFormattedValue method in MyValueFormatter, but i don't understand how can I fix this, or how implement this in the right way?

Upvotes: 1

Views: 1141

Answers (1)

David Rawson
David Rawson

Reputation: 21447

DataSet#getEntryForIndex(int index)

is the wrong method to call here. Entry in a DataSet are stored in a backing array and this method will get the Entry at that index in the backing array. This doesn't always correspond to the Entry for that x-value (the x-value on the chart). Hence, the IndexOutOfBoundsException.

You would want to do something this instead:

return (String) mDataSet.getEntryXPos(float value).getData();

See the javadoc for DataSet for further explanation

Upvotes: 3

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