Up vs. Back or in other terms hierarchy vs. chronology is one of the User Experience aspects touched upon in my post UML: Modelling User Interfaces Part 1 – Hierarchy and Navigation. The Android methodology for UI navigation has received some attention over the years and the largest change to date was brought in with the introduction of the Action Bar as part of Android 3.0+.

This is the first post in a series that looks at the modelling of User Interface (UI) related software using UML.

The main purpose of the post is to explore how we effectively model the navigation of a tree-like hierarchy, especially when considering the premise “In a tree structure there is one and only one path from any point to any other point”.

The tl;dr is that UML does not necessarily have the ability to represent UI concepts of hierarchy and navigation effectively.