Scroll finish listener of Line chart in mpandroidchart

Question

How to listen to the scroll finish event in mpandroidchart.

I overrided the OnChartGestureListener and OnChartValueSelectedListener but it does not seems to work. onChartTranslate() method gets callback even after the scroll gets end.

onChartGestureStart() gets called when the user touches the chart and onChartGestureEnd() gets called once the user stops touching the chart.

So, i need to catch the event which gets called when the scroll gets finished.

So, Can you give a headsup on how to listen to the scroll end of linechart in mpandroidchart.

You can refer this link https://github.com/PhilJay/MPAndroidChart/wiki/The-Axis — Stuti Kasliwal, Dec 18 '18 at 09:33

Mahesh Chandra · Answer 1 · 2019-03-05T15:29:59.817

this worked for me checked both the start and end of scroll in chart

chart.setOnTouchListener(new View.OnTouchListener() {
    @Override
    public boolean onTouch(View v, MotionEvent event) {
    if(!(chart.getLowestVisibleX() == chart.getXAxis().getAxisMinimum() || chart.getHighestVisibleX() == chart.getXAxis().getAxisMaximum())){
        // Do your work here
        Toast.makeText(getContext(),"Hello Scroll to end check working",Toast.LENGTH_LONG).show();
        return false;
    }
});

score 1 · Answer 2 · answered Dec 27 '18 at 08:06

1

You need to do something as follows:

@Override
        public void onChartGestureEnd(MotionEvent me, ChartTouchListener.ChartGesture lastPerformedGesture)
        {
            if(data.getEntryCount() == (int) chart.getHighestVisibleX())
            {
                // Do your work here
                Toast.makeText(getContext(),"Hello Scroll to end check working",Toast.LENGTH_LONG).show();
            }
        }

This will check if your scroll has reached for last value on x-Axis. You may need little bit customization in that but this is the way to do so.

answered Dec 27 '18 at 08:06

Muhammad Saad Rafique

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Thanks for your answer. OnChartGestureEnd gets called when the user takes finger from the chart. But it can't listen whether the chart is scrolling or not. I want to listen whether the chart has finished scrolling. Could you please help me on this – Kanagalingam Jan 02 '19 at 07:22
The check inside checks if you have finished scrolling. I know that this will trigger when the user remove finger from screen but the check inside check if chart is scrolled to the end along x-Axis or not. Implement this and check if its working or not then you will have the idea about what I am talking! – Muhammad Saad Rafique Jan 02 '19 at 08:11
Thanks for your reply. I tried your code. I don't want to check whether the scroll has reached the end of the chart (last value on x-Axis). My requirement is to get the center value of the chart when scroll event finishes. For example, Chart may have 1000 entries. When the user scrolls and the scroll event finishes near 500th entry in chart, I need to get that particular view port visible to the user to get the centre value. Am i clear to you else can i attach a image regarding my requirement bro.. Thanks – Kanagalingam Jan 02 '19 at 08:41

score 1 · Answer 3 · answered Feb 08 '20 at 13:11

the more better way is to use library's own listener with this logic like:

override fun onChartTranslate(me: MotionEvent?, dX: Float, dY: Float) {
                if(dX > 0){
                    //backward dragging
                }
                else if(mChart.highestVisibleX == mChart.xAxis.axisMaximum){
                    //forward dragging reached at max (can not be dragged more)
                }
            }

score 0 · Answer 4 · answered Jul 29 '22 at 14:41

I struggled with the same problem a lot. After i could not find solution, what i did is to set

chart.setDragDecelerationEnabled(false);

Thus there is no continuation of scrolling after touch up and i could get the last X coordinates with

  chart.setOnChartGestureListener(new OnChartGestureListener() {

        @Override
        public void onChartGestureStart(MotionEvent me, ChartTouchListener.ChartGesture lastPerformedGesture) {
        }

        @Override
        public void onChartGestureEnd(MotionEvent me, ChartTouchListener.ChartGesture lastPerformedGesture) {

            float lastX = holder.chart.getLowestVisibleX();
            saved_x.set(position,  lowX);
        }

});

Scroll finish listener of Line chart in mpandroidchart

4 Answers4