Apple Newton Utilities Guia do Utilizador descarregar pdf (Página 759)

100

101

CHAPTER 21

Routing Interface

Using Routing 21-11

The VerifyRoutingInfo method is passed two parameters, the target

information frame obtained by

GetTargetInfo, and the partially initialized item

frame obtained from

NewItem. The VerifyRoutingInfo method allows you a

chance to verify or change the target item before the routing slip is opened.

Normally you would return the same target frame that was passed in, possibly

modiﬁed. To cancel the routing operation, you can return

nil from this method.

Note that the system sends the VerifyRoutingInfo message only if it is imple-

mented by your application; otherwise, the routing operation continues without it.

If multiple items are being routed, the target object (constructed by

CreateTargeCursor) encapsulates them all. In your VerifyRoutingInfo

method, you can use the function

GetTargetCursor to return a cursor to

navigate the items. Then you can iterate through the cursor using the cursor

methods

Entry, Next, and Prev, as described in Chapter 11, “Data Storage and

Retrieval.” Note that only these three cursor methods are supported for use with

cursors returned by

GetTargetCursor.

Getting and Setting the Current Format 21

Next, the Routing interface sends your application base view the

GetDefaultFormat message. The purpose of this message is to get the default

format so that when the routing slip is opened, the format can be initially set to the

default. Normally, the default format for a particular transport is simply the last

format used with that transport from that application. This information is stored in

the

lastFormats slot of your application base view. Unless you want to do

something special, you don’t need to implement the

GetDefaultFormat method

because this is a root view method that is found by inheritance. The root view

method simply gets the default format symbol from the

lastFormats slot.

The format can be changed by the user, or by the system (if no last format is found,

the default is set to the ﬁrst one that is found). When the format is changed, the

Routing interface sends your application base view the

SetDefaultFormat

message. The purpose of this message is to store the default format symbol for later

use. Normally, this is stored in the

lastFormats slot in the application base

view. Unless you want to do something special, you don’t need to implement the

SetDefaultFormat method because this is a root view method that is found by

inheritance. The root view method simply sets the new format symbol in the

lastFormats slot of your application base view.

The

lastFormats frame contains a slot for each transport that has been used

from your application. Whenever a transport is selected, the system ﬁrst checks

your application for the

lastFormats frame and for a slot within that frame

named with the symbol of the transport being used. If the slot is found, it contains

the symbol of the last format used by that transport. Then the system searches for a

format whose

symbol slot matches it.

1 2 ... 754 755 756 757 758 759 760 761 762 763 764 ... 941 942

Comentários a estes Manuais

Sem comentários

Apple Newton Utilities Guia do Utilizador Página 759

Comentários a estes Manuais

Manuais e produtos relacionados com Software Apple Newton Utilities