StatisticsActivity.java

    public void showDatePickerDialog(final View v) {
        Calendar cal = Calendar.getInstance();

        DatePickerDialog datePickerDialog = new DatePickerDialog(v.getContext(),
                android.R.style.Theme_Holo_Light_Dialog_MinWidth,
                new DatePickerDialog.OnDateSetListener() {
                    @Override
                    public void onDateSet(DatePicker view, int year, int monthOfYear, int dayOfMonth) {
                        Calendar calendarInstance = Calendar.getInstance();
                        calendarInstance.set(year, monthOfYear, dayOfMonth);
                        ((EditText) v).setText(df.format(calendarInstance.getTime()));
                    }
                }, cal.get(Calendar.YEAR), cal.get(Calendar.MONTH), cal.get(Calendar.DATE));

        datePickerDialog.show();
    }