Android library dialog month picker
Date and Time
Android PickerView
This library allows you to create a completely customizable calendar
Android NTP time library. Get the true current time impervious to device clock time
Fully customizable calendar with a wide variety of features
Adaptation of the JSR-310 backport for Android
Easypeasy date functions
Building a better date/time library for Swift
Schedule timing task in Swift using a fluent API
Swift4 Date extension library