Firm foundation in the main hci principles, the book provides a working

7.4 Summary
In this chapter, we have studied one interactive application develop-
ment methodology called the MVC, which is based on the principle of 
the separation between the UI and core computational functionalities 
View/Controller
Model
Music Information
String FileName
ListEventList
SmartChordActivity
FileActivity
- Set up front end interface
- Show status (current file, tempo, ...)
- Select file
- Read file
- Set up model data structure
TempoActivity
- Select tempo
PlayActivity
- Read model data structure and
show chord information
Int Tempo
Figure 7.5 The MVC-based program structure for the No Sheets application introduced in 
Chapter 4.

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H U M A N – C O M P U T E R I N T E R A C T I O N 
of a given application. Such a separation of concerns allows for the 
two to be mixed and matched (for exploring different combinations 
of a proper set of functions and corresponding UIs) and lends itself 
to easier code maintenance. However, sometimes it is not very clear 
whether a given application can be cleanly separated into two parts, 
namely, the core function and UI. For example, suppose one is to 
implement several different “views” for different user groups for the 
same banking application, and yet another view for changing and 
selecting the views themselves. In this situation, it seems that the 
change-of-view functionality is one of the core functions and features 
of the application, yet in theory, the “view change” seems to belong to 
the View rather than the Model.
References
1. Olsen, Dan. 1998. Developing user interfaces: Interactive technologies. San 
Francisco, CA: Morgan Kaufman.
2. Krasner, Glenn E., and Stephen T. Pope. 1988. A cookbook for using the 
model-view controller user interface paradigm in SmallTalk-80. Journal 
of Object-Oriented Programming 1 (3): 26–49.

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8
U
S E R
I
N T E R FAC E
E
VA LUAT I O N
The last remaining part in the cycle of UI interactive software devel-
opment is the evaluation stage. Even if the developers may have 
strived to adhere to various HCI principles, guidelines, and rules 
and have applied the latest toolkits and implementation methodolo-
gies, the resulting UI or software is most probably not problem-free. 
Frequently, careful considerations in interaction and interface design 
may not even have been carried out in the first place. Aside from the 
fact that there may be things that the developer failed to oversee or 
consider, the overall development process was to be a gradual refine-
ment process to begin with, where the next refinement stages would 
be based on the evaluation results of the previous rounds. In this 
chapter, we will present several methods and examples of evaluation 
for user interfaces.