Apple Newton Utilities Uživatelská příručka stáhnout pdf (Strana 595)

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CHAPTER 16

Find

Using the Find Service 16-7

The only signiﬁcant difference between a date ﬁnd and a text ﬁnd is that a different

search method locates the items that are returned. To support text searches, you

must supply a

Find method. To support searching by date, you must supply a

DateFind method.

You can support any of these search methods independently of one another; for

example, you can implement the

Find method without implementing the

DateFind method.

You may also customize searches by adding a subset of data items from one

application to the Selected picker menu in the Find slip. Items added here may be,

for instance, a checkbook and ledger from a personal ﬁnance program.

A ﬁnder is a frame that enumerates items resulting from a Find operation. The

general characteristics of your ﬁnder are deﬁned by the proto it’s based on. The

system supplies two protos on which to base your ﬁnder: the

ROM_SoupFinder

or the

ROM_CompatibleFinder.

The

ROM_SoupFinder proto supports searching soup data. The

ROM_CompatibleFinder proto provides a framework, which you should

override, that supports searching data that is not soup based. When a ﬁnder based

on the

ROM_SoupFinder proto completes a search, it returns with a cursor which

is used to retrieve the found items from the application soup. When a ﬁnder based

on the

ROM_CompatibleFinder proto completes a search, it returns with the

actual found items in an array (the

items array).

If you store data in soups, there are standard ﬁnd methods deﬁned for the

ROM_SoupFinder proto that you can use. When you devise a different scheme,

you must use the

ROM_CompatibleFinder proto and deﬁne versions of the

ﬁnder methods that are tailored to your type of data storage.

After a search method scans your application’s data and returns a ﬁnder frame, you

must append it to the system-supplied

results array. Global and Selected ﬁnds

usually append more than one frame to this array, as multiple applications

complete their searches.

While a search continues, the system automatically provides user feedback on its

progress. When the search method completes, the system displays an overview list

of the items that were found.

For Global or Selected ﬁnds, each application (or data set, for a targeted data set

ﬁnd) in which items were found is identiﬁed by a heading, with the found items

listed under it. The application name that appears in this heading is supplied by the

title slot each application provides in its base view.

The system sends a

FindSoupExcerpt message to your application, which must

have a

FindSoupExcerpt method to respond to it. This method must extract and

return a string for the Find overview to display. If no items are found, the

FindSoupExcerpt message is not sent. If you are using the

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