How to set datelabels in Graphview (Android) exactly under the datapoint with the datevalue of the datapoint?

Question

I am using the Graphview with a DataPoint[] from a database. The DataPoint[] has the following datapoints:

1. [1.582381477E12/0.0] (date is 2020-02-22 14:24:37),
2. [1.58238148E12/1.0] (date is 2020-02-22 14:24:40),
3. [1.582381489E12/2.0] (date is 2020-02-22 14:24:49),
4. [1.582381491E12/3.0] (date is 2020-02-22 14:24:51),
5. [1.582381497E12/4.0] (date is 2020-02-22 14:24:57),
6. [1.582381511E12/5.0] (date is 2020-02-22 14:25:11)

I`m using this code for my GraphView:

    DataPoint[] dataPoints = getSucccessData(exercise.getExersiseNumber());
    LineGraphSeries<DataPoint> mLGS = new LineGraphSeries<>(dataPoints);
    mLGS.setDrawDataPoints(true);
    graphView = findViewById(R.id.gvGraphView);

    simpleDateFormat = new SimpleDateFormat("dd-M-yyyy hh:mm:ss");

    graphView.getGridLabelRenderer().setLabelFormatter(new DefaultLabelFormatter(){
        @Override
        public String formatLabel(double value, boolean isValueX) {

            if(isValueX){
                return simpleDateFormat.format(new Date((long)value));
            }
            else {
                return super.formatLabel(value, isValueX);
            }
        }
    });
        graphView.removeAllSeries();
        graphView.addSeries(mLGS);
        graphView.getViewport().setMinY(0);
        graphView.getViewport().setMaxY(5);
        graphView.getViewport().setYAxisBoundsManual(true);
        graphView.getViewport().setMinX(dataPoints[0].getX());
        graphView.getViewport().setMaxX(dataPoints[dataPoints.length - 1].getX());
        graphView.getGridLabelRenderer().setNumHorizontalLabels(dataPoints.length -1);
        graphView.getViewport().setXAxisBoundsManual(true);
        graphView.getGridLabelRenderer().setHumanRounding(false, true);
        graphView.getGridLabelRenderer().setHorizontalLabelsAngle(90);
        graphView.getViewport().setScrollableY(true);
        graphView.getViewport().setScrollableY(true);
        graphView.getViewport().setScalable(true);
        graphView.getViewport().scrollToEnd();
        graphView.getViewport().setScrollable(true);

The result ist this Graph:

As you can see the Xaxis labes are except from the first and the last one not the x-Values of my datapoints and they are not directly unter a specific datapoint. They are datevalues in a range between the first and the last x-Value of my datapoints and the distance between them is not the same. The more time is between the x-Values the more distance is between the datapoints.

I want to have the exact x-Value of my datapoints as Xaxis-Label, no other Xaxis-Labels and the distance between the datapoints should always be the same no matter how much time is between the dates.

How can I do this?