How can I use dates from a DatePicker element to be the x-axis values on a MPAndroidChart?

I am attempting to create a line graph using MPAndroidChart where the user enters a date (either today or a previous day) using a DatePicker and then enters a separate value for that date. The issue I am having is how to format that date from the DatePicker for saving it on a SQLite database, and then to take it out and use it for the x-axis of my graph. I have tried all of the different methods I have seen here and on the documentation, but they seem to be more for real-time data and not for graphs using previous days.

I am pretty much lost of the best way to go about this. Any help or advice would be apprecaited.

use custom valueformatter

class DateValueFormatter extends ValueFormatter {
    private SimpleDateFormat dateFormat = new SimpleDateFormat("dd-MM-yyyy");
    private List<Date> dateList;

    public DateValueFormatter(List<Date> dateList) {
        this.dateList = dateList;
    }

    @Override
    public String getAxisLabel(float value, AxisBase axis) {
        int axisValue = (int) value;
        if (axisValue >= 0 && axisValue < dateList.size()) {
            return dateFormat.format(dateList.get(axisValue));
        } else {
            return "";
        }
    }
}

and set xaxis value formatter

chart.getXAxis().setValueFormatter(new DateValueFormatter(datelist));