在自定义的一个Control上面显示一个ToolTip，它能显示节点的详细信息,如下图Dengues的实现:
它的实现代码在：
1 /**
2 * Qiang.Zhang.Adolf@gmail.com class global comment. Detailled comment <br/>
3 *
4 * $Id: Dengues.epf Qiang.Zhang.Adolf@gmail.com 2008-4-29 qiang.zhang $
5 *
6 */
7 public class WarehouseNodeToolTip extends ToolTip {
8
9 private final static int X_SHIFT;
10
11 static {
12 if ("gtk".equals(SWT.getPlatform()) || "carbon".equals(SWT.getPlatform())) {
13 X_SHIFT = -26;
14 } else {
15 X_SHIFT = -23;
16 }
17 }
18
19 private final static int Y_SHIFT = 1;
20
21 private IWarehouseNode node;
22
23 private final Control control;
24
25 /**
26 * Qiang.Zhang.Adolf@gmail.com WarehouseNodeToolTip constructor comment.
27 *
28 * @param control
29 */
30 public WarehouseNodeToolTip(Control control) {
31 super(control);
32 setShift(new Point(1, 1));
33 this.control = control;
34 }
35
36 /*
37 * (non-Javadoc)
38 *
39 * @see org.eclipse.jface.window.ToolTip#createToolTipContentArea(org.eclipse.swt.widgets.Event,
40 * org.eclipse.swt.widgets.Composite)
41 */
42 @Override
43 protected Composite createToolTipContentArea(Event event, Composite parent) {
44 Composite composite = createToolTipContentAreaComposite(parent);
45 addIconAndLabel(composite, WarehouseLabelUtil.getNodeIcon(node), node.getLabel());
46 IWarehouseObject object = node.getObject();
47 if (object != null) {
48 Object data2 = object.getData();
49 if (data2 instanceof Storage) {
50 addIconAndLabel(composite, null, ((Storage) data2).getComment());
51 }
52 }
53 return composite;
54 }
55
56 /**
57 * Qiang.Zhang.Adolf@gmail.com Comment method "addIconAndLabel".
58 *
59 * @param parent
60 * @param composite
61 */
62 private void addIconAndLabel(Composite composite, Image image, String label) {
63 Label imageLabel = new Label(composite, SWT.NONE);
64 imageLabel.setForeground(composite.getDisplay().getSystemColor(SWT.COLOR_INFO_FOREGROUND));
65 imageLabel.setBackground(composite.getDisplay().getSystemColor(SWT.COLOR_INFO_BACKGROUND));
66 imageLabel.setLayoutData(new GridData(GridData.HORIZONTAL_ALIGN_BEGINNING | GridData.VERTICAL_ALIGN_BEGINNING));
67 imageLabel.setImage(image);
68
69 Label textLabel = new Label(composite, SWT.NONE);
70 textLabel.setForeground(composite.getDisplay().getSystemColor(SWT.COLOR_INFO_FOREGROUND));
71 textLabel.setBackground(composite.getDisplay().getSystemColor(SWT.COLOR_INFO_BACKGROUND));
72 textLabel.setLayoutData(new GridData(GridData.FILL_HORIZONTAL | GridData.VERTICAL_ALIGN_CENTER));
73 textLabel.setText(removeTrailingNewline(DenguesTextUtil.getNotNullString(label)));
74 }
75
76 /**
77 * Qiang.Zhang.Adolf@gmail.com Comment method "removeTrailingNewline".
78 *
79 * @param text
80 * @return
81 */
82 private String removeTrailingNewline(String text) {
83 if (text.endsWith("\n")) {
84 return text.substring(0, text.length() - 1);
85 }
86 return text;
87 }
88
89 /*
90 * (non-Javadoc)
91 *
92 * @see org.eclipse.jface.window.ToolTip#getLocation(org.eclipse.swt.graphics.Point, org.eclipse.swt.widgets.Event)
93 */
94 @Override
95 public Point getLocation(Point tipSize, Event event) {
96 Widget widget = getTipWidget(event);
97 if (widget != null) {
98 Rectangle bounds = getBounds(widget);
99 if (bounds != null) {
100 return control.toDisplay(bounds.x + X_SHIFT, bounds.y + bounds.height + Y_SHIFT);
101 }
102 }
103 return super.getLocation(tipSize, event);
104 }
105
106 /*
107 * (non-Javadoc)
108 *
109 * @see org.eclipse.jface.window.ToolTip#shouldCreateToolTip(org.eclipse.swt.widgets.Event)
110 */
111 @Override
112 protected boolean shouldCreateToolTip(Event event) {
113 node = null;
114 if (super.shouldCreateToolTip(event)) {
115 Widget tipWidget = getTipWidget(event);
116 if (tipWidget != null) {
117 Rectangle bounds = getBounds(tipWidget);
118 if (bounds != null && control.getBounds().contains(bounds.x, bounds.y)) {
119 node = getWarehouseNode(tipWidget);
120 }
121 }
122 }
123 if (node == null) {
124 hide();
125 return false;
126 } else {
127 return true;
128 }
129 }
130
131 /**
132 * Qiang.Zhang.Adolf@gmail.com Comment method "getWarehouseNode".
133 *
134 * @param tipWidget
135 * @return
136 */
137 private IWarehouseNode getWarehouseNode(Widget hoverObject) {
138 if (hoverObject instanceof Widget) {
139 Object data = (hoverObject).getData();
140 if (data != null) {
141 if (data instanceof IWarehouseNode) {
142 return (IWarehouseNode) data;
143 }
144 }
145 }
146
147 return null;
148 }
149
150 private Rectangle getBounds(Widget widget) {
151 if (widget instanceof ToolItem) {
152 ToolItem w = (ToolItem) widget;
153 return w.getBounds();
154 }
155 if (widget instanceof TableItem) {
156 TableItem w = (TableItem) widget;
157 return w.getBounds();
158 }
159 if (widget instanceof TreeItem) {
160 TreeItem w = (TreeItem) widget;
161 return w.getBounds();
162 }
163 return null;
164 }
165
166 private Widget getTipWidget(Event event) {
167 Point widgetPosition = new Point(event.x, event.y);
168 Widget widget = event.widget;
169 if (widget instanceof ToolBar) {
170 ToolBar w = (ToolBar) widget;
171 return w.getItem(widgetPosition);
172 }
173 if (widget instanceof Table) {
174 Table w = (Table) widget;
175 return w.getItem(widgetPosition);
176 }
177 if (widget instanceof Tree) {
178 Tree w = (Tree) widget;
179 return w.getItem(widgetPosition);
180 }
181
182 return widget;
183 }
184
185 /**
186 * Qiang.Zhang.Adolf@gmail.com Comment method "createToolTipContentAreaComposite".
187 *
188 * @param parent
189 * @return
190 */
191 private Composite createToolTipContentAreaComposite(Composite parent) {
192 Composite composite = new Composite(parent, SWT.NONE);
193 GridLayout gridLayout = new GridLayout();
194 gridLayout.numColumns = 2;
195 gridLayout.marginWidth = 5;
196 gridLayout.marginHeight = 2;
197 composite.setLayout(gridLayout);
198 composite.setBackground(composite.getDisplay().getSystemColor(SWT.COLOR_INFO_BACKGROUND));
199 return composite;
200 }
201 }
202
还有在org.dengues.warehouse.viewers.WarehouseView的初始化函数中实现：
1 public void createPartControl(Composite parent) {
2 viewer = new WarehouseTreeViewer(parent, SWT.MULTI | SWT.H_SCROLL | SWT.V_SCROLL | SWT.BORDER);
3 WarehouseViewProvider denguesViewProvider = new WarehouseViewProvider(this);
4 viewer.setContentProvider(denguesViewProvider);
5 viewer.setLabelProvider(denguesViewProvider);
6 viewer.setSorter(new WarehouseViewNameSorter());
7 IViewSite viewSite = getViewSite();
8 viewer.setInput(viewSite);
9 getSite().setSelectionProvider(viewer);
10
11 makeActions();
12 hookContextMenu();
13 contributeToActionBars();
14 WarehouseViewFactory.initDragAndDrop(viewer);
15 hookDoubleClickAction();
16 nodeToolTip = new WarehouseNodeToolTip(viewer.getControl());//新建一个Tooltip
17 setPartName(Messages.getString("WarehouseView.Title.Name")); //$NON-NLS-1$
18 }
19
并添加两个Listener：
1 viewer.getTree().addFocusListener(new FocusAdapter() {
2
3 @Override
4 public void focusLost(FocusEvent e) {
5 nodeToolTip.hide();
6 }
7 });
8
9 viewer.getTree().addKeyListener(new KeyListener() {
10
11 public void keyPressed(KeyEvent e) {
12 if (e.keyCode == SWT.ESC) {
13 nodeToolTip.hide();
14 }
15 }
16
17 public void keyReleased(KeyEvent e) {
18 }
19
20 });
这样就可以了。
Dengues论坛(http://groups.google.com/group/dengues/),一个很好的Eclipse开发者乐园.