Swing I - Java - page 920

Display 17.11 Using Panels (part 4 of 4)

Resulting GUI (After clicking Gray button)

Adding Color
You color a JFrame as follows:

JFrame_Object .getContentPane().setBackground( Color );

If this is inside a constructor for the JFrame , then the expression simplifies to

getContentPane().setBackground( Color );

or the equivalent

this .getContentPane().setBackground( Color );

You color a button, label, or any other component (which is not a JFrame ) as follows:

Component_Object .setBackground( Color );

Note that getContentPane() is only used with a JFrame .
EXAMPLE (INSIDE A CONSTRUCTOR FOR A DERIVED CLASS OF JFrame )

getContentPane().setBackground(Color.WHITE);
JButton redButton = new JButton("Red");
redButton.setBackground(Color.RED);

The Container Class
The class called Containe r is in the java.awt package. Any descendent class of the
class Container can have components added to it (or, more precisely, can have compo-
nents added to objects of the class). The class JFrame is a descendent class of the class

Container