Apple Newton Programmer’s Newton 2.0 (for Newton 2.0) - Manual (Page 229)

C H A P T E R 6
Pickers, Pop-up Views, and Overviews
Overview Protos 6-29
The picker definition (described in the next section) is a data definition frame that
is provides the routines to create a name reference from an entry, an entry alias,
another name reference, a straight frame, or just to create a canonical empty name
reference (if no data is provided). It also retrieves the data from a name reference.
Finally, it provides some information about the name reference to support actions
like tapping and highlighting.
You also need to define the soup to query. Both this and the query specification can
be defined either in the data definition or in the list picker.
Using the Data Definitions Frame in a List Picker 6
The pickerDef slot of the list picker holds a data definition frame that determines
the overall behavior of the list picker. This frame should be based on
protoNameRefDataDef or protoPeopleDataDef , or at should least support
the required slots.
Here is an example:
pickerDef:= {
_proto: protoNameRefDataDef,
name: "Widgets",
class: '|nameRef.widget|,
entryType: 'widget,
soupToQuery:"Widgets",
querySpec: {indexPath: 'name},
columns: kColumns,
};
Specifying Columns 6
The columns slot hold an array that determines how the columns in the list picker
are displayed. Here’s an example of column specification array:
columns:= [{
fieldPath:'name,// path for field to display in column
optional:true,// not required -- unnamed widget
tapWidth:155},// width for checkbox & name combined
{
fieldPath:'price,// path for field to display
in column
optional:nil,// price is required
tapWidth:0}];// width -- to right end of view