Java Reference
In-Depth Information
}
Directory "Sketcher 5 displaying a font dialog"
The
JSplitPane
constructor does it all. The first argument specifies that the pane supports two com-
ponents, one above the other. You can probably guess that for side-by-side components you specify
JSplitPane.HORIZONTAL_SPLIT
. If the second constructor argument is
true
, the components are redrawn
continuously as the divider is dragged. If it is
false
the components are not redrawn until you stop dragging
the divider.
The third argument is the component to go at the top, or to the left for
HORIZONTAL_SPLIT
, and the fourth
argument is the component to go at the bottom, or to the right, as the case may be.
NOTE
You don't need to do it here, but you can change the components in a split pane.
You have four methods to do this:
setLeftComponent()
and
setRightComponent()
for a
horizontal arrangement of the panes, and
setTopComponent()
and
setBottomComponent()
for a vertical arrangement of the panes. You just pass a reference to the component you
want to set to whichever method you want to use. There are also corresponding
get
meth-
ods to retrieve the components in a split pane. You can even change the orientation by call-
ing the
setOrientation()
method and passing either
JSplitPane.HORIZONTAL_SPLIT
or
JSplitPane.VERTICAL_SPLIT
to it.
There is a facility to provide a widget on the divider to collapse and restore either pane. You don't need
it, but if you want to try this here, you can add the following statement after the
JSplitPane
constructor
call:
splitPane.setOneTouchExpandable(true);
Calling this method with the argument as
false
removes the widget.
After you have created the
splitPane
object, you add it to the
dataPane
panel with constraints that make
it fill the full width of the container.
Next you can add the font size selection mechanism.
Using a Spinner
You could use another list for this, but to broaden your horizons you use another Swing component, a
javax.swing.JSpinner
object. A
JSpinner
object displays a sequence of numbers or objects, and the user
can select any one from the set. The spinner displays up and down arrows at the side of the spinner for step-
ping through the list. You can also use the keyboard up and down arrow keys for this.
The sequence of choices in a spinner is managed by a
javax.swing.SpinnerModel
object. There are
three concrete spinner model classes defined in the
javax.swing
package. The one you use depends on
what sort of items you are choosing from:
•
SpinnerNumberModel
is a model for a sequence of numbers. Numbers are stored internally and
returned as type
Number
, which is the superclass of the classes that encapsulate the primitive nu-
