Feb 14, principles 1

1
Feb 14, principles 12

• Focus on users and their tasks
• Identify the users
• Clarify the purpose (goal software helps users
  achieve)
• What advantage does the software offer (what do
  users like or dislike about status quo)
• What will the users have to learn or do
  differently to use the software?
• What conceptual model do the users already have
  about their task and the data they use to perform
  it?
• What are the skills or expertise of the user
  pertaining to the goal tasks?
• Become acquainted with representative users,
  collaborate with them in the task domain.
• Conduct a detailed task analysis (understand the
  context of the task domain and the relative
  importance of task)

2
Consider Function, Then Presentation

• Doesnt mean do GUI last
• What mental model does the user bring to the GUI?
• What data does the GUI permit the user to
  manipulate? What manipulations does the user
  want to do?
• What options controls, settings, and choices does
  the GUI make available to the user what are the
  defaults, and with what frequency does the user
  need to modify these settings?
• Create a conceptual model, not an interface
  description, keep it simple, make it correspond
  to tasks (clarify the types of objects processed
  and the kinds of actions performed on them).

3
Function, cont

• Develop a lexicon of terminology relating to each
  user-visible concept
• Write task scenarios (user cases)
• Outline criteria for product documentation and
  usability testing
• Make first cut at implementation architecture by
  considering objects identified

4
Chapter 15 Intermediate Containers

• JPanel (grouping container)
• Generally opaque with painted backgrounds
• Set layout manager individually (setLayout() or
  constructor option)
• Use add() methods to place component in panel
• tutorial example
• Text example
• ScrollPane (for large or growable displays)
• Assign client component upon construction, add to
  contentPane (if at preferred size, no scroll
  bars)
• Works with Jviewport for pictures
• Uses JScrollBar and can use other objects such as
  the illustrated Rule and Corner.
• On-line description
• Scrolling-Savvy Client
• This term is used to describe a client that
  implements the Scrollable interface whose 5
  methods provide information to the ScrollPane on
  how far to scroll when either a button or the
  track of the ScrollBar is clicked.

5
Intermediate cont

• Sizing
• When you put a client in a scroll pane it gives
  it to a JViewPort object which interacts with the
  ScrollPanes scrollBars to compute what is
  painted in the ScrollPanes center.
• The ScrollPanes dimensions are determined
• By the size of the container that holds it
• By its PreferredSize setting
• By the size of its 9 components.
• Its default preferredSize is to display its
  viewport at its perferredSize but this may not be
  possible if it has to display row and column
  headers in addition to the viewport.
• If the client is scrolling-savvy, the client will
  give the the viewport its preferredViewportSize
  which, if less than the actual size
  (perferredSize) will indicate scrollbars.
• Once realized the ScrollPane displays a computed
  portion of its client. If the perferredSize of
  the client changes, the ScollPane will not know
  this until client.revalidate() is executed to
  force all of the layout managers to re-compute.

6
Intermediate, cont

• Split Pane
• Usually the components are themselves
  ScrollPanes.
• Construtor with three arguments(dir, client1,
  client2)
• The focus is on the divider bar
• Horizontal or Vertical splits
• SetOneTouchExpandable(true)
• setDividerLocation(150) or (.25) means left/top
  percentage
• Initial sizes of each split area, range of motion
• Set Minimum size of component (down to 0)
• Perferred size of components (default?minimum)
• Can change components with setLeftComponent or
  setTopComponent
• Can add() but only twice (must remove to
  repopulate)
• Tabbed Pane
• Use add() to place other panes in tabs
• Takes as arguments label, icon, panel, and
  tool tip