Architecture of NewtApp

Layout Layer

This layer is responsible for displaying soup entries and scrolling:

Displaying soup entries
This layer uses a specified user interface (that is, what a display looks like on the Newton) to view a soup entry. A layout layer is also associated with a particular soup and will only display entries from that soup.

Soup registration
This layer is responsible for a given soup. It calls RegUnionSoup when a layout is opened and UnRegUnionSoup when it is closed.

Scrolling between entries
This layer handles scrolling forward and backward between entries. Different layout layers can handle scrolling differently.

Some layout layers want to display one entry at a time, while others might want to roll through entries so that they appear attached end to end. For example, the Names application displays only one entry at a time, and tapping the scroll arrows scrolls one entry at a time. A different layout type is used for the overview, where a number of rows are displayed, one per entry. Tapping the scroll arrows scrolls many rows at once. Yet another kind of layout is used by the Notepad. Here, entries are variable-sized and more than one may appear in the layout. Tapping the scroll arrows scrolls the entries. Entries may scroll off, and others may scroll on.


An online version of Programming for the Newton using Macintosh, 2nd ed. ©1996, 1994, Julie McKeehan and Neil Rhodes.

Last modified: 1 DEC 1996