A GridBagConstraints object specifies the location and
area of the component's display area within the container
and how the component is laid out inside its
display area. The GridBagConstraints, in conjunction
with the component's minimum size and the preferred size of the
component's container, determines where the component is placed
within the applet.
The GridBagConstraints() constructor is trivial
GridBagConstraints gbc = new
GridBagConstraints();
Your interaction with a GridBagConstraints object
takes place through its eleven fields and fifteen mnemonic
constants.
I'll demonstrate by showing you how to lay out this calculator.
Notice that it has a TextField and 18 buttons of
varying sizes, and naturally lends itself to a description as a
grid.
The discussion assumes that you have imported all the necessary
classes, particularly java.awt.GridBagLayout,
java.awt.GridBagConstraints, java.awt.Button
and java.awt.TextField. It also assumes you have
created a GridBagConstraints object named
displayConstraints like this
GridBagConstraints displayConstraints = new
GridBagConstraints();