Navigation management occurs in a mobile device during a directory up-down
scroll and it involves a user interface and a directory (e.g., mobile
directory of photos). The directory is a tree-shaped hierarchy of nodes
such that any node on the directory is selectable by a user via the user
interface. This way navigation can flow up-down through the directory.
Additionally, the navigation management involves associating a state and
one or more action items with each node and saving the state. The state
is an expanded or collapsed condition of the node. If the state of a
particular node is expanded, additional nodes at a lower level of the
hierarchy are presented to the user. If its state is collapsed only that
particular node is presented and the other nodes are hidden. The user
interface includes for any node selected by the user its associated one
or more action items.