Now that you know how to design a Palm application, let’s describe its two components. After that we will look at how they communicate with each other.
Most Palm solutions are composed of a handheld application and desktop conduit:
The handheld portion has an icon that is displayed in the application list. Users will usually use the Palm Install Tool from a Windows or Macintosh machine to install your application (it’ll be installed on the next synchronization).
When a user puts a Palm OS device in its cradle and presses the HotSync button, the handheld application begins communicating with the desktop conduit. For example, the Address Book has a built-in conduit that synchronizes the address book information on the handheld with the address book information in the Palm Desktop PIM. If a new entry has been made in either place, it is copied to the other. If an entry has been modified either place, it is copied to the other. If an entry has been deleted in one place, it is usually deleted in the other.
Third parties provide other conduits that replace the Address Book conduit so that the device’s address book synchronizes with other PIMs (Microsoft Outlook, for example). You’ll usually want to write a conduit for your application’s database that will upload/download information in a manner appropriate for your application.
For example, the Expense conduit reads the expense information from the handheld, fills in a spreadsheet based on the information, and then deletes the information from the handheld. From the users’ point of view, this is ideal; they get their information in a standard, easy-to-use form: a spreadsheet on the desktop. The Palm OS application doesn’t have to worry about creating reports; its only purpose is recording expense information.
If you don’t want to write your own conduit, then a backup conduit is provided. It backs up any database that:
Doesn’t already have a conduit responsible for it
Has been marked as a database that should be backed up
Note
There have been four different Windows versions of HotSync shipped to users (1.0, 1.1, 2.0, and 3.0). You’ll probably want to target HotSync 1.1 or later. It’s also reasonable to target HotSync 3.0, since it is available by download from http://www.palm.com.
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