Deactivation 2 – Apple Newton Programmer’s Newton 2.0 (for Newton 2.0) User Manual

Page 78

C H A P T E R 2

Getting Started

2-6

Package Loading, Activation, and Deactivation

IMPORTANT

Any changes that you make to the system in the

InstallScript

function must be reversed in the

RemoveScript

function. For example, if you register your

application for certain system services or install print formats,
stationery, or other objects in the system, you must reverse
these changes and remove or unregister these objects in the

RemoveScript

function. If you fail to do this, such changes

cannot be removed by the user, and if your application is on a
card, they won’t be able to remove the card without getting a
warning message to put the card back.

▲

Only applications and auto parts use the

InstallScript

function. Note that the

InstallScript

function takes one extra argument when used for an auto part.

Applications built using the NewtApp framework require special

InstallScript

and

RemoveScript

functions. For details, see Chapter 4,

“NewtApp Applications.”

Deactivation

The

RemoveScript

function in a package part is executed when an application or

auto part is deactivated.

This function lets you perform any special deinstallation operations that you need
to do, any clean-up, and any unregistration for system services that you registered
for in the

InstallScript

function.

Note that automatically removed auto parts do not use the

RemoveScript

function since such auto parts are removed immediately after the

InstallScript

is executed—the

RemoveScript

is not executed.

In addition to the

RemoveScript

function, another function,

DeletionScript

is executed when the user removes a package by deleting it from the Extras
Drawer. This function applies to all types of frame parts, and is actually executed
before the

RemoveScript

function.

The

DeletionScript

function is optional. It lets you do different clean-up

based on the assumption that the user is permanently deleting a package, rather
than simply ejecting the card on which it happens to reside. For example, in the

DeletionScript

function, you might want to delete all the soups created by the

application—checking with the user, of course, before performing such an
irreversible operation.