Frames, panels and layouts - An Introduction to Graphical User Interfaces with Java Swing - page 17

Figure 2.4 A frame generated by SimplePanelFrameDriver with a border layout. Note
that the panel at 'West' has been constructed with width 50 and height 20. While the width
is obeyed, the height has changed to fill the available space

specified by the constants CENTER , NORTH , SOUTH , EAST and WEST . These constants
are defined in class BorderLayout ; see Figure 2.5a). If a border component is not
present, then the central component extends in that direction. The central com-
ponent usually contains the main information. The border components contain
additional information such as a status bar in the 'South'-component. To insert a
component childComp into the content pane at location pos we use method

this .getContentPane().add(childComp,pos)

where pos is one of the constants BorderLayout.CENTER , BorderLayout.NORTH ,
BorderLayout.SOUTH , BorderLayout.EAST or BorderLayout.WEST .
The code for class SimplePanelFrame and the listing for the driver class
SimplePanelFrameDriver follow. The first class is derived from SimpleFrame .
The five panels are created in its constructor and then embedded into the content
pane. The driver class generates a SimplePanelFrame and makes it visible. The
result is shown in Figure 2.4. There one can see that all the border panels are sized
to span the entire width or height of the content pane. The other dimensions are
the default width and height, which are 10 on most platforms. The white panel
CPWest at 'West' has width 50 as specified in its constructor. The height specifi-
cation of 20 is ignored in the layout; the height of panel CPWest is extended to fill
the available height inside the frame. The central component is also extended to
fill all the space in the middle.

File: its/SimpleFrameWithPanels/SimplePanelFrame.java

package its.SimpleFrameWithPanels; 1.

2.
3.

import java.awt.*;

import javax.swing.JFrame; 4.

import its.SimpleFrame.SimpleFrame; 5.

6.