Handling Selections
The JList
class in Swing depends on a second model, this one to monitor the
elements that have been selected by the user. As with the list data
model, the programmer is given a wide latitude of control when
dealing with selections. Swing uses a simple interface for models
that handle list
selections—ListSelection-Model — and
also provides a default
implementation—DefaultListSelection-Model.
The ListSelectionModel Interface
The ListSelectionModel
interface outlines the methods
necessary for managing list selections. Selections are represented by
a series of ranges, where each range is defined by its endpoints. For
example, if the elements “One,” “Two,”
“Three,” “Six,” “Seven,” and
“Nine” were selected in the opening example of the
chapter, the list selection model would contain three entries that
specified the ranges {1,3} and {6,7} and {9,9}. All selection range
endpoints are zero-based. If only one element is present in a range,
such as with “Nine,” both endpoints are identical.
Properties
Table 7.5 shows the properties of the
ListSelectionModel interface. The first four
properties of the list selection model can be used to retrieve
various indices in the list that are currently selected. The
anchorSelectionIndex
and
leadSelectionIndex properties represent the anchor
and lead indices of the most recent range of selections. The
maxSelectionIndex
and
minSelectionIndex properties return the largest and smallest selected index in the entire list, respectively. ...
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