Apple 2 manual Roll Views

C H A P T E R 2

Container Views

Roll Views

In a roll view several discrete, fixed-size subviews are arranged one above another like pictures on a filmstrip. A roll view invariably contains more subviews than can be displayed in full detail at once. To see a subview that’s not currently displayed, a user can scroll through the subviews. Alternatively, a user can see an overview consisting of one-line subview titles.

In most applications, users don’t find roll views useful. Studies show that users tend not to use scrolling to access different subviews, finding it easier to pick from a list than to remember the relative position of subviews. Usually it makes more sense to implement the subviews of a roll view as individual slips, and list their titles in an overview. For example, the overviews of the built-in Preferences and Formulas applications list the titles of individual slips, and users cannot scroll from slip to slip.

For more information on scrolling and overview, see “Scrolling” on page 2-36 and “Overview” beginning on page 2-44.

Roll views bear some resemblance to the paper roll structure of the Notepad, but there are several major distinctions. For one, users can create new notes in the Notepad but cannot create new subviews in a roll view. Users can also vary the length of notes in the Notepad, but a roll view’s subview sizes are fixed. Moreover, a roll view’s summary cannot scroll and can display at most 16 one-line subview descriptions. There can be more than 16 subviews; to see beyond the 16th subview, a user must scroll subview by subview, starting with the 16th one.

Roll Views 2-27