Advanced Swing Containers - The Definitive Guide to Java Swing - page 404

JViewport Class
The JViewport component is rarely used on its own outside a JScrollPane . It normally lives
within the center of a JScrollPane and uses the ViewportLayout manager to respond to posi-
tioning requests to display a part of a large Component within a smaller space. In addition to
residing in the center of a JScrollPane , JViewport is also used for the row and column headers
of a JScrollPane .

Creating a JViewport
There's only one constructor for creating a JViewport : the no-argument version: public
JViewport() . Once you've created the JViewport , you place a component within it by using
setView(Component) .

JViewport Properties
Table 11-10 shows the 13 properties of JViewport . Setting the layout manager to something
other than ViewportLayout is possible but not recommended because the layout manager
makes the JViewport do its work properly.

Table 11-10. JViewport Properties
Property Name

Data Type Access

accessibleContext AccessibleContext Read-only

border Border Write-only

changeListeners ChangeListener[ ] Read-only

extentSize Dimension Read-write

insets Insets

Read-only

optimizedDrawingEnabled boolean Read-only

scrollMode int Read-write

UI ViewportUI

Read-write bound

UIClassID String Read-only

view Component Read-write

viewPosition Point Read-write

viewRect Rectangle Read-only

viewSize Dimension Read-write

Because of scrolling complexity and for performance reasons, the JViewport doesn't support
a border. Trying to change the border to a non- null value with setBorder(Border) throws an