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1 package com.sshtools.ui.swing;
2
3 import java.awt.BorderLayout  ;
4 import java.awt.Component ;
5 import java.awt.Dimension ;
6 import java.awt.Point ;
7 import java.awt.event.ActionEvent ;
8 import java.awt.event.ActionListener ;
9 import javax.swing.JButton ;
10 import javax.swing.JPanel ;
11 import javax.swing.JViewport ;
12 import javax.swing.plaf.basic.BasicArrowButton ;
13
14 public class ScrollingPanel extends JPanel implements ActionListener {
15
16 protected JButton north;
17 protected JButton south;
18 protected JViewport viewport;
19 protected int incr = 48;
20
21 public ScrollingPanel(Component component) {
22 setLayout(new BorderLayout ());
23 north = new BasicArrowButton (BasicArrowButton.NORTH);
24 south = new BasicArrowButton (BasicArrowButton.SOUTH);
25 viewport = new JViewport ();
26 add(north, BorderLayout.NORTH);
27 add(viewport, BorderLayout.CENTER);
28 add(south, BorderLayout.SOUTH);
29 viewport.setView(component);
30 north.addActionListener(this);
31 south.addActionListener(this);
32 setAvailableActions();
33 }
34
35 public void setIncrement(int incr) {
36 this.incr = incr;
37 }
38
39 public void actionPerformed(ActionEvent event) {
40 Dimension view = new Dimension (getSize().width, getSize().height - north.getPreferredSize().height - south.getPreferredSize().height);
41 Dimension pane = viewport.getView().getPreferredSize();
42 Point top = viewport.getViewPosition();
43 if (event.getSource() == north) {
44 if (top.y < incr) {
45 viewport.setViewPosition(new Point (0, 0));
46 } else {
47 viewport.setViewPosition(new Point (0, top.y - incr));
48 }
49 }
50 if (event.getSource() == south) {
51 int max = pane.height - view.height;
52 if (top.y > (max - incr)) {
53 view = viewport.getExtentSize();
54 max = Math.max(pane.height - view.height, 0);
55 viewport.setViewPosition(new Point (0, max));
56 } else {
57 viewport.setViewPosition(new Point (0, top.y + incr));
58 }
59 }
60 setAvailableActions();
61 }
62
63 public void setAvailableActions() {
64 Dimension view = getSize();
65 Dimension pane = viewport.getView().getPreferredSize();
66 Point top = viewport.getViewPosition();
67 }
70 }
71 |
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Java API By Example, From Geeks To Geeks.