Mpandroidchart: remove old data in real time ploting

[avrpic8]

Hi everybody,
I would like to draw data in real time , then remove old data.
I found this code but in latest version of mpandroidchart I cant find this metho,
so what should I do? please help me.

in latest version of library ,What is the alternative to this command?:
== set.getValues() ==
//================================================================
private static final int VISIBLE_NUM = 5;

private void refreshData(float value) {
LineData data = mChart.getData();
if (data != null) {
// at least one entry exists
LineDataSet set = data.getDataSetByIndex(0); // should not be null, because we created it before
set.setColor(Color.BLUE);
set.setDrawCircleHole(false);
set.setValueTextSize(9f);
data.addDataSet(set);
// check and remove oldest entry
if(set.getEntryCount() == VISIBLE_NUM) {
set.removeEntry(0); // remove oldest
// change Indexes - move to beginning by 1
for (Entry entry : set.getValues()) {
entry.setX(entry.getX() - 1);
}
}
// add Entry to the end of Line with X position = getEntryCount(), Y pos as = value
data.addEntry(new Entry(set.getEntryCount(), value), 0);
} else {
// create all necessary stuff on the first run
ArrayList dataSets = new ArrayList<>(); // create
data = new LineData(dataSets); // create

       LineDataSet mySet = new LineDataSet(null, getString(R.string.my_graph_name)); // create empty
       mySet.setColor(Color.BLUE);
       // ..... the rest of settings
       data.addDataSet(mySet); // should be assigned to parent BEFORE adding new Entry
       data.addEntry(new Entry(mySet.getEntryCount(), value), 0); // add FIRST Entry to single mySet with index=0
       mChart.setData(data);
    }

// notify about changes
mChart.notifyDataSetChanged();
mChart.invalidate();
}

/////////////////////////////////////
Thank you and best regard.

[avrpic8]

Is it correct? but not work yet, please help.

    `LineData` dataChart = mainChart.getData();

    if (dataChart != null) {

        ILineDataSet set = dataChart.getDataSetByIndex(0);

        if (set == null) {
            set = createSet(ColorTemplate.rgb(colorChart),ColorTemplate.rgb(colorFill));
            dataChart.addDataSet(set);
        }

        dataChart.addEntry(new Entry(set.getEntryCount(),sensorEvent.values[2]),0);
        dataChart.notifyDataChanged();

        if(set.getEntryCount() > 20){
            set.removeFirst();
            dataChart.notifyDataChanged();
        }

        // let the chart know it's data has changed
        mainChart.notifyDataSetChanged();
        // limit the number of visible entries
        mainChart.setVisibleXRangeMaximum(20);
        mainChart.moveViewToX(dataChart.getEntryCount());``

and when use this method my chart become ,

and when I remove this code "if(set.getEntryCount())......"
and then mainChart.setVisibleXRangeMaximum(20) to mainChart.setVisibleXRangeMaximum(300) become correct.

so,what should I do to remove old data from the chart?

[salceson]

We have something like this in the code in utility class:

public class ChartUtils {
    private static final int MAX_ENTRIES = 50;
    // (more code, irrelevant for the issue...)
    public static void removeOutdatedEntries(DataSet... dataSets) {
        for (DataSet ds : dataSets) {
            while (ds.getEntryCount() > MAX_ENTRIES) {
                ds.removeFirst();
            }
        }
    }
}

We call it like this:

ChartUtils.removeOutdatedEntries(dataSet);
lineData.notifyDataChanged();
chart.notifyDataSetChanged();
chart.invalidate();

It works perfectly :)

[avrpic8]

Hi my bro thanks for your answer,
but I have the same problem yet.
This is my output result:
(I set Max Entry to 50) -> when I use the bottom code the result is correct.

`

    dataChart = mainChart.getData();

    if (dataChart != null) {

        set = (LineDataSet) dataChart.getDataSetByIndex(0);
        if (set == null) {
            set = createSet(ColorTemplate.rgb(colorChart), ColorTemplate.rgb(colorFill));
            dataChart.addDataSet(set);
        }


        dataChart.addEntry(new Entry(set.getEntryCount(), sensorEvent.values[2]), 0);
        dataChart.notifyDataChanged();
        //ChartUtils.removeEntries(set);
        mainChart.notifyDataSetChanged();
        mainChart.invalidate();

        mainChart.setVisibleXRangeMaximum(MAX_ENTRIES);
        mainChart.moveViewToX(dataChart.getEntryCount());
    }

and when I use this code again the output is incorrect.
`dataChart = mainChart.getData();

    if (dataChart != null) {

        set = (LineDataSet) dataChart.getDataSetByIndex(0);
        if (set == null) {
            set = createSet(ColorTemplate.rgb(colorChart), ColorTemplate.rgb(colorFill));
            dataChart.addDataSet(set);
        }


        dataChart.addEntry(new Entry(set.getEntryCount(), sensorEvent.values[2]), 0);
        dataChart.notifyDataChanged();
        ChartUtils.removeEntries(set);
        mainChart.notifyDataSetChanged();
        mainChart.invalidate();

        //mainChart.setVisibleXRangeMaximum(MAX_ENTRIES);
        //mainChart.moveViewToX(dataChart.getEntryCount());
    }`

As you can see in the second case,points are connected vertically.
So what is wrong?

There is my other part of my code.
` private void initMainChart() {

    mainChart = (LineChart) findViewById(R.id.mainChart);

    //mainChart.getAxisLeft().setDrawGridLines(false);
    mainChart.getAxisRight().setDrawGridLines(false);
    mainChart.getAxisRight().setDrawLabels(false);
    //mainChart.getXAxis().setDrawGridLines(false);
    //mainChart.getAxisLeft().setDrawLabels(false);
    //mainChart.getXAxis().setDrawLabels(false);

    mainChart.setDescription(desc);
    //mainChart.setBackgroundColor(Color.LTGRAY);

    // setting Left Axis
    YAxis leftAxis = mainChart.getAxisLeft();
    leftAxis.setAxisMaximum(30f);
    leftAxis.setAxisMinimum(-30f);

    LineData data = new LineData();
    // add empty data
    mainChart.setData(data);

    //mainChart.animateX(1000);
    ///mainChart.animateXY(500,500);
    //mainChart.setTouchEnabled(false);
    //mainChart.setHardwareAccelerationEnabled(true);
    mainChart.setDrawBorders(true);
    mainChart.setDragEnabled(false);

    //mainChart.setVisibleYRangeMaximum(set.getYMax() + 12, YAxis.AxisDependency.LEFT);
`}

` private LineDataSet createSet(int colorChart, int colorFill) {

    LineDataSet set = new LineDataSet(null, "Dynamic Data");
    //set.setAxisDependency(YAxis.AxisDependency.LEFT);
    set.setColor(colorChart);
    //set.setDrawCircles(false);
    set.setCircleRadius(4f);
    set.setLineWidth(3f);
    //set.setDrawFilled(true);
    set.setFillColor(colorFill);
    set.setFillAlpha(65);
    set.setDrawHighlightIndicators(false);
    //set.setHighLightColor(Color.rgb(244, 117, 117));
    set.setDrawValues(false);
    return set;
}`

` private static class ChartUtils{

    public static void removeEntries(DataSet... dataSets) {

        for(DataSet ds: dataSets){

            while (ds.getEntryCount() > MAX_ENTRIES) {
                ds.removeFirst();
                ds.notifyDataSetChanged();
            }
        }
    }
}`

again, please help me and I am waiting for your answer.
Thanks sir,
best regard.

[salceson]

This is happening due to the fact that you are adding entries to chart instead of data set.
Instead of this line:

dataChart.addEntry(new Entry(set.getEntryCount(), sensorEvent.values[2]), 0);

try:

set.addEntry(new Entry(set.getEntryCount(), sensorEvent.values[2]));

As no data is added to set, the set.getEntryCount() is returning same value all the time and that's why you have data with same x coordinate.

[avrpic8]

Hi ,thanks for your answer my bro.
I try a lot but I have the same problem.
I dont Where is my mistake?
I'm so confused.
this is my code :
`dataChart = mainChart.getData();

    if (dataChart != null) {

        DataSet set = (DataSet) dataChart.getDataSetByIndex(0);
        if (set == null) {
            set = createSet(ColorTemplate.rgb(colorChart), ColorTemplate.rgb(colorFill));
            dataChart.addDataSet((LineDataSet) set);
        }


        ChartUtils.removeEntries(set);
        set.addEntry(new Entry(set.getEntryCount(), sensorEvent.values[2]));
        dataChart.notifyDataChanged();

        mainChart.notifyDataSetChanged();
        mainChart.invalidate();

} private static class ChartUtils{

    public static void removeEntries(DataSet... dataSets) {

        for(DataSet ds: dataSets){

            while (ds.getEntryCount() > MAX_ENTRIES) {
                ds.removeFirst();
                //ds.notifyDataSetChanged();
            }
        }
    }
}`

Is it a bug in this version?,I dont know.
It seems no different between dataChart.addEntry and set.addEntry when I add them.
please help
thank you again.

[avrpic8]

Hi everybody,
The problem was solved.
I should add this lines.

if(set.getEntryCount() == MAX_ENTRIES) { set.removeFirst(); // change Indexes - move to beginning by 1 for (Entry entry : set.getValues() entry.setX(entry.getX() - 1); }

[royseberg]

The last comment by avrpic8 worked fine for me. Now I'm working with Visual C# on a similar line Chart and I need to implement the same solution to the problem of removing the first entry in a series, and the problem is that the series then collapses, so any suggestions on how to "translate" the following method for reordering the series:

       for(Entry entry : set.getValues() entry.setX(entry.getX() -1)

in Visual C# ???
Thanks in advance.