This chapter addresses the following issues:
What makes a cross-device system feel coherent (see page 4)
Why it’s complicated to understand how an IoT system works, and how
we might help users with this (see page 7)
Deciding on the best way to distribute functionality between different
devices in the system (see page 14).
Determining which UI elements and interactions need to be consistent
across devices, and which don’t (see page 25).
Dealing with data and content synchronization issues in the UI (see page
31).
Designing interactions that require switching between devices (see page
39).
Cross-platform UX and usability
Many of the tools of UX design and HCI originate from a time when an
interaction was usually a single user using a single device. This was almost
always a desktop computer, which they’d be using to complete a work-like
task, giving it more or less their full attention.
The reality of our digital lives moved on from this long ago. Many of us own
multiple internet-capable devices such as smartphones, tablets and connected
TVs, used for leisure as well as work. They have different form factors, may
be used in different contexts and some of them come with specific sensing
capabilities, such as mobile location.
Cross-platform UX is an area of huge interest to the practitioner community.
But academic researchers have given little attention to defining the properties
of good cross-platform UX. This has left a gap between practice and theory
that needs addressing.
In industry practice cross-platform UX has often proceeded device by device.
Designers begin with a key reference device and subsequent interfaces are
treated as adaptations. In the early days of smartphones this reference device
was often the desktop. In recent years the ‘mobile first’ approach has