Java Reference
In-Depth Information
Display 17.5
The Color Constants
Color.BLACK
Color.BLUE
Color.CYAN
Color.DARK_GRAY
Color.GRAY
Color.GREEN
Color.LIGHT_GRAY
Color.MAGENTA
Color.ORANGE
Color.PINK
Color.RED
Color.WHITE
Color.YELLOW
The class
Color
is in the
java.awt
package.
EXAMPLE:
A GUI with a Label and Color
Display 17.6 shows a class for GUIs with a label and a background color. We have
already discussed the use of color for this window. The label is used to display the text
string
"Close-window button works."
The label is created as follows:
JLabel aLabel
=
new
JLabel("Close-window button works.");
The label is added to the
JFrame
with the method
add
as shown in the following line
from Display 17.6:
add(aLabel);
The GUI class
ColoredWindow
in Display 17.6 programs the close-window button as
follows:
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
This way, when the user clicks the close-window button, the program ends. Note that
if the program has more than one window, as it does in Display 17.6, and the user
clicks the close-window button in any one window of the class
ColoredWindow
, then
the entire program ends and all windows go away.
Note that we set the title of the
JFrame
by making it an argument to
super
rather
than an argument to
setTitle
. This is another common way to set the title of a
JFrame
.
If you run the program
DemoColoredWindow
in Display 17.6, then the two windows
will be placed one on top of the other. To see both windows, you need to use your
mouse to move the top window.
