1 import java.awt.BorderLayout;
2 import java.awt.Color;
3 import java.awt.GridLayout;
4 import javax.swing.JFrame;
5 import javax.swing.JLabel;
6 import javax.swing.JPanel;
7 import javax.swing.JSlider;
8 import javax.swing.event.ChangeListener;
9 import javax.swing.event.ChangeEvent;
10
11 public class ColorViewerFrame extends JFrame
12 {
13 private static final int FRAME_WIDTH = 300;
14 private static final int FRAME_HEIGHT = 400;
15
16 private JPanel colorPanel;
17 private JSlider redSlider;
18 private JSlider greenSlider;
19 private JSlider blueSlider;
20
21 public ColorViewerFrame()
22 {
23 colorPanel = new JPanel();
24
25 add(colorPanel, BorderLayout.CENTER);
26 createControlPanel();
27 setSampleColor();
28 setSize(FRAME_WIDTH, FRAME_HEIGHT);
29 }
30
31 public void createControlPanel()
32 {
33 class ColorListener implements ChangeListener
34 {
35 public void stateChanged(ChangeEvent event)
36 {
37 setSampleColor();
38 }
39 }
40
41 ChangeListener listener = new ColorListener();
42
43 redSlider = new JSlider(0, 255, 255);
44 redSlider.addChangeListener(listener);
45
46 greenSlider = new JSlider(0, 255, 175);
47 greenSlider.addChangeListener(listener);
48
49 blueSlider = new JSlider(0, 255, 175);
50 blueSlider.addChangeListener(listener);
51
52 JPanel controlPanel = new JPanel();
53 controlPanel.setLayout(new GridLayout(3, 2));
54
55 controlPanel.add(new JLabel("Red"));
56 controlPanel.add(redSlider);
57
58 controlPanel.add(new JLabel("Green"));
59 controlPanel.add(greenSlider);
60
61 controlPanel.add(new JLabel("Blue"));
62 controlPanel.add(blueSlider);
63
64 add(controlPanel, BorderLayout.SOUTH);
65 }
66
67 /**
68 Reads the slider values and sets the panel to
69 the selected color.
70 */
71 public void setSampleColor()
72 {
73 // Read slider values
74
75 int red = redSlider.getValue();
76 int green = greenSlider.getValue();
77 int blue = blueSlider.getValue();
78
79 // Set panel background to selected color
80
81 colorPanel.setBackground(new Color(red, green, blue));
82 colorPanel.repaint();
83 }
84 }