GraphView format label discard some digits for very big data

Question

I am using graphview library and trying to format label of graph to time in 'HH' format from millisecond. I give each x value of datapoint in series as millisecond which is really big like '1.442440833138E12'. And after that i make my custom LabelFormatter like below:

        @Override
        public String formatLabel(double value, boolean isValueX) {
            if (isValueX) {
                SimpleDateFormat format = new SimpleDateFormat("HH");

                Date date = new Date((long) value);
                Log.i("formatLabel", Double.toString(date.getTime()));
                return format.format(date);
            } else {
                return super.formatLabel(value, isValueX);
            }
        }

But when i looked at my graph, it was not same to what i put in, like when i put millisecond equal to 07 hour, the graph showed 11 hour or 01 hour as i change using setNumHorizontalLabels. So i tried to find what was wrong, and when i put log output code up that formatLabel method, the log output was like below:

09-17 20:03:50.287  28093-28093/? I/formatLabel﹕ 1.44243E12
09-17 20:03:50.287  28093-28093/? I/formatLabel﹕ 1.44244E12
09-17 20:03:50.287  28093-28093/? I/formatLabel﹕ 1.44245E12
09-17 20:03:50.287  28093-28093/? I/formatLabel﹕ 1.44246E12
09-17 20:03:50.292  28093-28093/? I/formatLabel﹕ 1.44247E12

which is supposed to look like '1.442440833138E12'. I also tried to make custom DefaultFormatter with number precision with minimum '12' digits but result was same.

Can someone explain to me why this happens?

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Here's my code of adding datapoints into each series.

DataPoint[] data1=new DataPoint[SIZE] ;
for(int i=0;i<SIZE;i++)
{
  data1=new DataPoint(new Date(time),value) ;
  //test whether x prints all full millisecond
  Log.i("formatLabel", Double.toString(data1.getX()));

}

LineGraphSeries<DataPoint> series=new LineGraphSeries(data1) ;

when i saw a log output when i give each datapoint's x value with date, i get full millisecond notation like '1.442440833138E12'. But in my custom formatLabel instance above, it is truncated. I hope user can get my problem more clearly and give me some solution...

score 1 · Accepted Answer · answered Sep 17 '15 at 11:25

You should add date/times to a series like this:

series.appendData(new DataPoint(new Date(time), value), true, Integer.MAX_VALUE);

And format the label like this:

graph.getGridLabelRenderer().setLabelFormatter(
        new DateAsXAxisLabelFormatter(getActivity(),
                        SimpleDateFormat.getDateInstance(SimpleDateFormat.SHORT)) {
            @Override
            public String formatLabel(double value, boolean isValueX) {
                if (isValueX)
                    return super.formatLabel(value, isValueX);
                else
                    // format Y-axis label
            }
        });

(the example uses the default short SimpleDateFormat instance)

Looking at your label formatting code: there is no need to instantiate SimpleDateFormat for each data point.

_@M66B_Thanks for comment. I tried your way but didn't work though. I edited my post with code of creating datapoint with date and adding datapoint array into series. — 강신욱, Sep 17 '15 at 12:55
Try using *Integer.toString* instead of *Double.toString*. A time is not a floating point number, but an integer. — M66B, Sep 17 '15 at 13:25

GraphView format label discard some digits for very big data

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1 Answers1