v.3.0.0-beta1 BarChart: ArrayIndexOutOfBoundsException when formatter applied, granularity is enabled and there's only one data point

[antohama]

Hi, I've faced an ArrayIndexOutOfBoundsException under following conditions:

• AxisValueFormatter is applied to x axis, where formatted value is an item of a list;
• granularity is enabled for x axis;
• the data consists of only one value.

Here's the stacktrace:

java.lang.ArrayIndexOutOfBoundsException: length=12; index=-1
at java.util.ArrayList.get(ArrayList.java:310)
at com.example.asuprun.tempconverter.AnotherActivity$1.getFormattedValue(AnotherActivity.java:65)
at com.github.mikephil.charting.components.AxisBase.getFormattedLabel(AxisBase.java:451)
at com.github.mikephil.charting.components.AxisBase.getLongestLabel(AxisBase.java:437)
at com.github.mikephil.charting.renderer.XAxisRenderer.computeSize(XAxisRenderer.java:78)
at com.github.mikephil.charting.renderer.XAxisRenderer.computeAxisValues(XAxisRenderer.java:73)
at com.github.mikephil.charting.renderer.XAxisRenderer.computeAxis(XAxisRenderer.java:66)
at com.github.mikephil.charting.charts.BarLineChartBase.notifyDataSetChanged(BarLineChartBase.java:339)
at com.github.mikephil.charting.charts.Chart.setData(Chart.java:318)
at com.example.asuprun.tempconverter.AnotherActivity.plotData(AnotherActivity.java:88)
at com.example.asuprun.tempconverter.AnotherActivity.toggleData(AnotherActivity.java:98)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:270)
at android.view.View.performClick(View.java:4780)
at android.view.View$PerformClick.run(View.java:19866)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5254)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)

Simplified code:

public class AnotherActivity extends AppCompatActivity {
    private ViewGroup chartView;
    private Map<String, Integer> data;
    private BarChart chart;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.chart_layout);

        chartView = (ViewGroup) findViewById(R.id.chart_view);
        chart = new BarChart(this);
        data = new LinkedHashMap<>();
        data.put("6/15", 36);
        data.put("8/15", 23);
        chartView.addView(chart);
        plotData();
    }

    private void plotData() {
        chart.clear();
        final ArrayList<String> xVals = new ArrayList<>();
        ArrayList<BarEntry> yVals = new ArrayList<>();

        for (Map.Entry<String, Integer> entry : data.entrySet()) {
            yVals.add(new BarEntry(xVals.size(), entry.getValue()));
            xVals.add(entry.getKey());
        }

        XAxis xAxis = chart.getXAxis();
        xAxis.setDrawGridLines(false);
        xAxis.setPosition(XAxis.XAxisPosition.BOTTOM);
        xAxis.setGranularityEnabled(true);
        xAxis.setValueFormatter(new AxisValueFormatter() {
                                    @Override
                                    public String getFormattedValue(float value, AxisBase axis) {
                                        try {
                                            return xVals.get((int) value);
                                        } catch (IndexOutOfBoundsException e) {
                                            e.printStackTrace();
                                            return "stub";
                                        }
                                    }

                                    @Override
                                    public int getDecimalDigits() {
                                        return 0;
                                    }
                                }
        );

        chart.getAxisRight().setEnabled(false);
        YAxis axisLeft = chart.getAxisLeft();
        axisLeft.setAxisMinValue(0f);
        axisLeft.setGranularityEnabled(true);
        axisLeft.setGranularity(1f);

        BarDataSet dataSet = new BarDataSet(yVals, "Data");
        BarData barData = new BarData(dataSet);
        barData.setBarWidth(0.7f);
        chart.setData(barData);
        chart.invalidate();
    }

    public void toggleData(View view) {
        if (data.size() > 1) {
            data.remove("8/15");
        } else {
            data.put("8/15", 23);
        }
        plotData();
    }
}

[PhilJay]

The crash occurred in the code that you yourself wrote. The only one who can prevent this crash from happening is you yourself.

When using the formatters of course you need to be aware that the value coming from the formatter might not fit any array or list you use in the formatter.

Offtopic: As a personal recommendation I suggest to never simply place code into a try-catch block for preventing crashes. But this is more of a stackoverflow topic.

[antohama]

Hi Phil! Thank you for your comment!
In this case formatter rely on the data list, which the values for chart are taken from, too.
Thus it cannot be predicted that its value don't fit the list. The issue appears due to extra values on both edges of the list, which is handled by the library. Shouldn't it provide means then to take care of formatting of those extra values?

[levianye]

I also meet such question,it seems label count be increased in the lib AxisRenderer.java in the function computeAxisValues,maybe we can rewrite it by self

[gao746700783]

i just solved this problem;
cause you used a custom valueFormatter,so,when reset chart data,you should reset your custom valueFormatter,it may help

[eprabhakar]

Well, I too got into the same problem, but with @PhilJay suggestion, I got a work around as follows

All you need to do is to change the method implementation from 

public String getFormattedValue(float value, AxisBase axis) {
            // "value" represents the position of the label on the axis (x or y)
             return mValues[(int) value];
}

To the following

public String getFormattedValue(float value, AxisBase axis) {
           // "value" represents the position of the label on the axis (x or y)
           if(mValues.length > (int) value) {
                return mValues[(int) value];
            } else return null;
 }

@PhilJay, please let me know if the above approach is OK.

[skh1993]

@gao746700783 I want to know how do you solve? how to reset valueFormatter

[antohama]

@skh1993 I think gao means calling setValueFormatter(null) on axis.

[skh1993]

antohama
Did you solve this problem?

[antohama]

@skh1993
yes, I'm checking whether the value is out of the list and return desired string in such case.

The concern that @antohama has raised is genuine.

Thanks much @eprabhakar , your solution did work for me

[MatheusDinni]

Anyone having the issue yet? I'm facing the same problem and no suggestions above worked for me :/

[MatheusDinni]

@eprabhakar i changed your return statement from null to "" and worked for me.

[mkamals1989]

gao746700783 : How did you reset the value formatter? Could you pls share the code for that?

[santhosh285]

Thanks to @PhilJay for this great library 👍

Thanks @eprabhakar & @antohama 👏

The below code solved the crash.

xAxis.setValueFormatter(new IAxisValueFormatter() {
            @Override
            public String getFormattedValue(float value, AxisBase axis) {
                if (value >= 0) {
                    if (mValues.length > (int) value) {
                        return mValues[(int) value];
                    } else return "";
                } else {
                    return "";
                }
            }
        });

NB: But it will not plot the line graph. So for the best result add a dummy value before it and make the data list size as two. And works all perfect.