public void setUnitTextAppearance(int resId) {
        applyTextAppearance(getContext(), resId, unitLabelViews);
    }
Sets the text appearance for the small unit lables ("h", "m", "s") in the upper display area.

@param resId resource id of the style describing the text appearance.
android/third_party/time-duration-picker/src/main/java/mobi/upod/timedurationpicker/TimeDurationPicker.java