UIOverlayView – painting on top of your subviews
My first baby steps are becoming toddler steps and the first classes of a generic library are forming. I have found that making my infamous calendar picker part of my technology shake-down projects, usually forces me to code parts that are very educational. So by now there is a Swing version (JCalendarPicker), a JavaFX 1.3 version (FXCalendarPicker, part of JFXtras) and soon an iOS version (KPCalendarPicker). The Swing version actually was very straight forward. The JavaFX version required me to build a spinner component for the year and month selection. The iOS had the same requirements as JFX, because the default UIPickerView takes up way too much space on the screen to be used as a subcomponent for CalendarPicker. So I developed KPMiniPickerView which basically is UIPickerView on the scale of a text field.
KPMiniPicker has the looks of a text field, but I needed some way to visually make it different, so users know that it is not a text field. I decided to do this by painting blue arrows on top of the childeren, showing the direction in which the minipicker could be slided.