Java Reference
In-Depth Information
Summarizing, the following steps are necessary to use a grid-bag layout for
embedding components comp0 ,... compK ,... compN into parent component
parent :
Sketch the desired layout on paper and determine how many rows and columns
are necessary. Also determine the weights you want to use.
Create an instance gbl of GridBagLayout and assign it to parent by par-
ent.setLayout(gbl) .
For every component compK to be embedded do the following:
(a) Create an instance constraintsK of GridBagConstraints and set the pa-
rameters.
(b) Link the constraints constraintsK to compK using gbl.setConstraints-
(compK,constraintsK).
(c) Embed compK into parent by parent.add(compK) (or parent
.getContentPane().add(compK) in case parent is a frame).
Creating and setting the constraints for every component would result in many
lines of nearly identical code. In the example application GridBagFrame we de-
fined a private method easyConstraints that does all this work. It receives the
constraint values, the component and the layout as arguments. It then creates an
instance of GridBagConstraints , sets the values, and links constraints and com-
ponents. The field fill is always set to BOTH . The GUI created by this program is
shown in Figure 17.4.
Figure 17.4 The result of application GridBagFrame
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