17. models of the system


This exercise is based on the mobile phone scenario on the book website at: www.hcibook.com/e3/scenario/phone/.

List the main elements of the state of the phone (you can use programming language variable declarations for this) and then write down a step-by-step walkthrough of the state as the user accesses a shortcut at position '3' as in steps C.1C.10 of scenario C.

answer available for tutors only

If students have already done exercise 16.6, then they can be asked to make sure that this answer is consistent with their answer to that as the details of the state depend on fleshing out the design in the online scenario.

If they have not done 16.6 then the answer to this will include some design decisions.
Answer clearly needs to be consistent with answer to (ii) and with scenario:

  • State description (here in C syntax), may have one 'state' variable or one for menu and one for sub-menu one for state in sub-menu. Here just have single (most likely solution)

state description

Annotated scenario

The calculator worked example uses a tabular style, but the following is more an annotation of the scenario. Either is acceptable, The reason for not using tabular style here is simply space as the descriptions of each step are more complex than the simple key presses for the calculator.

scenario annotation

Other exercises in this chapter

ex.17.1 (ans), ex.17.2 (ans), ex.17.3 (ans), ex.17.4 (ans), ex.17.5 (tut), ex.17.6 (tut), ex.17.7 (tut), ex.17.8 (tut), ex.17.9 (tut), ex.17.10 (tut)

all exercises for this chapter