Datapoint Index in Marker

[anbuck]

I'm trying to implement the deletion of data points. The user touches a data point and the marker appears and includes a delete button. However, for this to work, I need the data point index so that I know which data point to delete. The Highlight class contains a dataset index and a data index, but no data point index.

[Priyanshi-Z]

Can you give more details with some example of code like what you have done so far to achieve it.

[sahruday]

By having dataset Index, we can remove and pass the values to the chart again to redraw the graph, make sure you are calling notifyDataSetChanged() except for Pie Chart.

[anbuck]

The issue is that there is no way directly to tell the index of the datapoint that was clicked, so instead I have to loop through all of the datapoints in that dataset index and try to match the values to the datapoint that was clicked. Here is an example for a time-based line graph:

public String onTooltipRefresh(final int datasetIndex, final float datapointX, final float datapointY)
{
    if (displayTooltipCallback != null)
    {
        final Date datapointDate = new Date(minTimestampFinal + (Math.round((double)datapointX) * DateConstants.MILLISECONDS_PER_MINUTE));

        // The graphing library doesn't give us the data point index that was clicked, so we have to look through all of the data to find it
        final LineChartDataset<Date, Double> dataset = lineDatasets.get(datasetIndex);
        for (int i = 0; i < dataset.getXValues().size(); ++i)
        {
            // Due to floating point error, we have to approximate the X into a date value
            if (Math.abs(dataset.getXValues().get(i).getTime() - datapointDate.getTime()) < (DateConstants.MILLISECONDS_PER_MINUTE * 5)
                    && dataset.getYValues().get(i).floatValue() == datapointY)
            {
                return displayTooltipCallback.onDisplayTooltipText(datasetIndex, i, Float.toString(datapointY));
            }
        }
    }

    return null;
}

[sahruday]

We have chartTouchListeners for every chart in it we can override onSingelTapUp(MotionEvent e)

override fun onSingleTapUp(e: MotionEvent?): Boolean {
                if (e != null) {
                    val highlight = mChart?.getHighlightByTouchPoint(e.x, e.y)
                    if (highlight != null) {
                        val x = highlight.x.toInt()
                        val entry = chart.data.dataSet.getEntryForIndex(x)
                    }
                }
                return super.onSingleTapUp(e)
            }

Here we can get Index and entry by using highlight

[barbeau]

One way to accomplish this is to add the index to the Entry in the data when first creating it:

data.addEntry(new Entry(x, y, dataSet.getEntryCount() + 1), GRAPH_DATA);

And then you can retrieve it from the Entry after it's tapped:

  public void refreshContent(Entry e, Highlight highlight) {

    textView.setText("Index: " + (int) e.getData()));
    ...