Using Dates With The Graphview Library

I'm using GraphView library (see: https://github.com/jjoe64/GraphView or http://www.jjoe64.com/p/graphview-library.html) But I would like to use Date/Time for the X-as. Does anyone

Solution 1:

This is the correct way to do this

You just have to use the unix timestamp (seconds from 1.01.1970) as x value.

Then you can set a custom label formatter and convert the unix timestamp to a String:

final java.text.DateFormatdateTimeFormatter= DateFormat.getTimeFormat(mActivity);

LineGraphViewgraphView=newLineGraphView(mActivity, entry.getValue()) {
    @Overrideprotected String formatLabel(double value, boolean isValueX) {
        if (isValueX) {
            // transform number to timereturn dateTimeFormatter.format(newDate((long) value*1000));
        } else {
            returnsuper.formatLabel(value, isValueX);
        }
    }
};

Solution 2:

GraphView is a great library to use, i find it the easiest as well. The first step in doing this would be to add a String Variable in the GraphViewData Class within GraphView.java. Like So:

staticpublicclassGraphViewData {
    publicfinaldouble valueX;
    publicfinaldouble valueY;
    publicfinal String valueDate;

    publicGraphViewData(double valueX, double valueY,String valueDate) {
        super();
        this.valueX = valueX;
        this.valueY = valueY;
        this.valueDate = valueDate;
    }
}

When you create your GraphViewData object when creating a GraphView Graph, you will need to add the date data in string form (along with the X and Y).

Lets say you have 80 data points in your graph (index 0 - 79). There is a method within GraphView that is responsible for generating and returning the horizontal labels, i believe its called generateHorLabels. Instead of just returning the X Value (0-79), Use the X value to get the String from the GraphData object.

In the code you have now, it should have the following in a for loop

labels[i] = formatLabel(min + ((max-min)*i/numLabels), true);

instead of the above, you could do something like this.

Double temp =  Double.valueOf(formatLabel(min + ((max-min)*i/numLabels), true));
int rounded =(int)Math.round(temp); 
labels[i] = values[rounded].valueDate;

Hope this helped!

Solution 3:

Here's the updated answer from jjoe64, with the x-values obtained from Date#getTime()

finalDateFormatdateTimeFormatter= DateFormat.getDateTimeInstance();        
    graphView = newLineGraphView(context, "Chart");
    graphView.setCustomLabelFormatter(newCustomLabelFormatter() 
    {
        @Overridepublic String formatLabel(double value, boolean isValueX) 
        {
            if (isValueX)
            {
                return dateTimeFormatter.format(newDate((long) value));
            }
            returnnull; // let graphview generate Y-axis label for us
        }
    });

Solution 4:

I created the horizontal labels at the same time I was setting the values:

publicvoidinitializeLineGraphView() {

    // Get last weeks entries from the DB
    ArrayList<Entry> entries = DbManager.getInstance().getLastWeeksEntries(newDate());
    String[] hLabels = newString[entries.size()];
    GraphView.GraphViewData[] graphViewData = newGraphView.GraphViewData[entries.size()];

    for(inti=0; i < entries.size(); i++) {

        Entryentry= entries.get(i);
        intpain= entry.getPain();
        graphViewData[i] = newGraphView.GraphViewData(i, pain);

        // Generate the horizontal labelsSimpleDateFormatsdf=newSimpleDateFormat("EEE");
        StringdayOfWeek= sdf.format(entry.getDate());
        hLabels[i] = dayOfWeek;

    }

    mSeries = newGraphViewSeries("", null, graphViewData);
    GraphViewgraphView=newLineGraphView(getActivity(), "");
    graphView.addSeries(mSeries);
    graphView.setHorizontalLabels(hLabels);
    graphView.setVerticalLabels(newString[] {"10", "5", "0"});
    mLineGraphView = graphView;

}