@Override
            public void onStartTrackingTouch(final @NonNull RangeSlider slider) {
                if (grace == null) {
                    grace = (slider.getValueTo() - slider.getValueFrom()) / 20.0f;
                }
                lastThumb = slider.getActiveThumbIndex(); // on touch start it's the active thumb
                final List<Float> values = slider.getValues();
                if (lastThumb >= 0 && lastThumb < values.size()) {
                    lastValue = values.get(lastThumb);
                } else {
                    lastValue = null;
                }
            }
View displays and maintains a slider where user can select single or range of items from a sorted item list.
Tapping on a thumb allows manual value input
main/src/main/java/cgeo/geocaching/ui/ContinuousRangeSlider.java