Prentice.Hall.Introduction.to.Java.Programming,.Brief.Version.9th.(2014).[sharethefiles.com]

17.7 Sliders 659
4
5 public class SliderDemo extends JFrame {
6 // Create horizontal and vertical sliders
7 private JSlider jsldHort = new JSlider(JSlider.HORIZONTAL);
8 private JSlider jsldVert = new JSlider(JSlider.VERTICAL);
9
10 // Create a MessagePanel
11 private MessagePanel messagePanel =
12 new MessagePanel("Welcome to Java");
13
14 public static void main(String[] args) {
15 SliderDemo frame = new SliderDemo();
16 frame.setTitle("SliderDemo");
17 frame.setLocationRelativeTo(null); // Center the frame
18 frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
19 frame.pack();
20 frame.setVisible(true);
21 }
22
23 public SliderDemo() {
24 // Add sliders and message panel to the frame
25 setLayout(new BorderLayout(5, 5));
26 add(messagePanel, BorderLayout.CENTER);
27 add(jsldVert, BorderLayout.EAST);
28 add(jsldHort, BorderLayout.SOUTH);
29
30 // Set properties for sliders
31 jsldHort.setMaximum(50);
32 jsldHort.setPaintLabels(true);
33 jsldHort.setPaintTicks(true);
34 jsldHort.setMajorTickSpacing(10);
35 jsldHort.setMinorTickSpacing(1);
36 jsldHort.setPaintTrack(false);
37 jsldVert.setInverted(true);
38 jsldVert.setMaximum(10);
39 jsldVert.setPaintLabels(true);
40 jsldVert.setPaintTicks(true);
41 jsldVert.setMajorTickSpacing(10);
42 jsldVert.setMinorTickSpacing(1);
43
44 // Register listener for the sliders
45 jsldHort.addChangeListener(new ChangeListener() {
46 @Override /** Handle scroll-bar adjustment actions */
47 public void stateChanged(ChangeEvent e) {
48 // getValue() and getMaximumValue() return int, but for better
49 // precision, use double
50 double value = jsldHort.getValue();
51 double maximumValue = jsldHort.getMaximum();
52 double newX = (value * messagePanel.getWidth() /
53 maximumValue);
54 messagePanel.setXCoordinate((int)newX);
55 }
56 });
57 jsldVert.addChangeListener(new ChangeListener() {
58 @Override /** Handle scroll-bar adjustment actions */
59 public void stateChanged(ChangeEvent e) {
60 // getValue() and getMaximum() return int, but for better
61 // precision, use double
62 double value = jsldVert.getValue();
63 double maximumValue = jsldVert.getMaximum();
horizontal slider
vertical slider
create frame
create UI
slider properties
listener
listener