MPAndroidChart with null values

Question

I\'m using the MPAndroidChart and am really enjoying it.

A \'little\' need I have is that I can put null values to the \'entrys\'. I\'m monitoring the apache conecti

Answer 1

My solution is to draw another DataSet with TRANSPARENT (or arbitrary) color: - chart with fixed number of X values - Y values are updated periodically - boolean flag indicate transparent part (or another color)

private static final int SERIES_SIZE = 360; 
int xIndex = -1;
float xIndexVal;
private LineChart chart;
private boolean currentFlag;

public void createChart(LineDataSet dataSet) {
    LineData chartData = new LineData();
    prepareDataSet(dataSet);
    chartData.addDataSet(dataSet);
    for (int i = 0; i < SERIES_SIZE; i++) {
        chartData.addXValue("" /*+ i*/);
    }
    chart.setData(chartData);

}

private void prepareDataSet(LineDataSet dataSet, YAxis axis, int color) {
    // configure set 
}


public void update(Float val, boolean flag) {
    List dsl = chart.getData().getDataSets();
    Log.d("chart", String.format("%s --- %d sets, index %d", descr,  dsl.size(), xIndex));

    if (xIndex == SERIES_SIZE - 1) {

        // remove all entries at X index 0
        for (int i = 0; i < chart.getData().getDataSetCount(); i++) {
            Entry entry0 = chart.getData().getDataSetByIndex(i).getEntryForIndex(0);
            if (entry0 != null && entry0.getXIndex() == 0) {
                chart.getData().removeEntry(entry0, i);
                Log.d("chart", String.format("entry 0 removed from dataset %d, %d entries in the set", i, chart.getData().getDataSetByIndex(i).getEntryCount()));
            }
            else {
                Log.d("chart", String.format("all %d entries in the set kept", chart.getData().getDataSetByIndex(i).getEntryCount()));
            }
        }

        // remove empty set, if any
        for (Iterator mit = dsl.iterator(); mit.hasNext(); ) {
            if (mit.next().getEntryCount() == 0) {
                mit.remove();
                Log.d("chart", String.format("set removed, %d sets", dsl.size()));
            }
        }

        // move all entries by -1
        for (ILineDataSet ds : dsl) {
            for (Entry entry : ((LineDataSet)ds).getYVals()) {
                entry.setXIndex(entry.getXIndex() - 1);
            }
        }
    }
    else {
        xIndex++;
    }

    if (currentFlag != flag) {
        currentFlag = !currentFlag;
        LineDataSet set = new LineDataSet(null, "");
        prepareDataSet(set, chart.getAxisLeft(), currentFlag ?  Color.TRANSPARENT : Color.BLUE);
        chart.getData().addDataSet(set);

        if (xIndex != 0) {
            chart.getData().addEntry(new Entry(xIndexVal, xIndex - 1), dsl.size() - 1);
        }
    }

    xIndexVal = val;

    chart.getData().addEntry(new Entry(val, xIndex), dsl.size() - 1);

    chart.notifyDataSetChanged();
    chart.invalidate();
}