Graphics and Java 2D - Java: How to Program Early Objects - page 563

The JColorChooser component (package javax.swing ) enables application users to
select colors. Figures 13.7-13.8 demonstrate a JColorChooser dialog. When you click the
Change Color button, a JColorChooser dialog appears. When you select a color and press
the dialog's OK button, the background color of the application window changes.

1 // Fig. 13.7: ShowColors2JFrame.java

2 // Choosing colors with JColorChooser.

3 import java.awt.BorderLayout;

4 import java.awt.Color;

5 import java.awt.event.ActionEvent;

6 import java.awt.event.ActionListener;

7 import javax.swing.JButton;

8 import javax.swing.JFrame;

9
10

import javax.swing.JColorChooser;

import javax.swing.JPanel;

11
12 public class ShowColors2JFrame extends JFrame

13 {

14 private final JButton changeColorJButton;

15 private Color color = Color.LIGHT_GRAY ;

16 private final JPanel colorJPanel;

17
18

// set up GUI

19

public ShowColors2JFrame()

20 {

21 super( "Using JColorChooser" );

22
23 // create JPanel for display color

24 colorJPanel = new JPanel();

25 colorJPanel.setBackground(color);

26
27 // set up changeColorJButton and register its event handler

28 changeColorJButton = new JButton( "Change Color" );

29 changeColorJButton.addActionListener(

30 new ActionListener() // anonymous inner class

31 {

32 // display JColorChooser when user clicks button

33 @Override

34 public void actionPerformed(ActionEvent event)

35 {

36 color = JColorChooser.showDialog(

ShowColors2JFrame. this , "Choose a color" , color); 37

38
39 // set default color, if no color is returned

40 if (color == null )

41 color = Color.LIGHT_GRAY ;

42
43 // change content pane's background color

44 colorJPanel.setBackground(color);

45 } // end method actionPerformed

46 } // end anonymous inner class

47 ); // end call to addActionListener

Fig. 13.7 | Choosing colors with JColorChooser . (Part 1 of 2.)