TreeEditor


1   /*******************************************************************************
2    * Copyright (c) 2000, 2007 IBM Corporation and others.
3    * All rights reserved. This program and the accompanying materials
4    * are made available under the terms of the Eclipse Public License v1.0
5    * which accompanies this distribution, and is available at
6    * http://www.eclipse.org/legal/epl-v10.html
7    *
8    * Contributors:
9    *     IBM Corporation - initial API and implementation
10   *******************************************************************************/
11  package org.eclipse.swt.custom;
12  
13  
14  import org.eclipse.swt.*;
15  import org.eclipse.swt.events.*;
16  import org.eclipse.swt.graphics.*;
17  import org.eclipse.swt.widgets.*;
18  
19  /**
20  *
21  * A TreeEditor is a manager for a Control that appears above a cell in a Tree and tracks with the
22  * moving and resizing of that cell.  It can be used to display a text widget above a cell
23  * in a Tree so that the user can edit the contents of that cell.  It can also be used to display
24  * a button that can launch a dialog for modifying the contents of the associated cell.
25  *
26  * <p> Here is an example of using a TreeEditor:
27  * <code><pre>
28  *   final Tree tree = new Tree(shell, SWT.BORDER);
29  *   for (int i = 0; i &lt; 3; i++) {
30  *       TreeItem item = new TreeItem(tree, SWT.NONE);
31  *       item.setText("item " + i);
32  *       for (int j = 0; j &lt; 3; j++) {
33  *           TreeItem subItem = new TreeItem(item, SWT.NONE);
34  *           subItem.setText("item " + i + " " + j);
35  *       }
36  *   }
37  *   
38  *   final TreeEditor editor = new TreeEditor(tree);
39  *   //The editor must have the same size as the cell and must
40  *   //not be any smaller than 50 pixels.
41  *   editor.horizontalAlignment = SWT.LEFT;
42  *   editor.grabHorizontal = true;
43  *   editor.minimumWidth = 50;
44  *   
45  *   tree.addSelectionListener(new SelectionAdapter() {
46  *       public void widgetSelected(SelectionEvent e) {
47  *           // Clean up any previous editor control
48  *           Control oldEditor = editor.getEditor();
49  *           if (oldEditor != null) oldEditor.dispose();
50  *   
51  *           // Identify the selected row
52  *           TreeItem item = (TreeItem)e.item;
53  *           if (item == null) return;
54  *   
55  *           // The control that will be the editor must be a child of the Tree
56  *           Text newEditor = new Text(tree, SWT.NONE);
57  *           newEditor.setText(item.getText());
58  *           newEditor.addModifyListener(new ModifyListener() {
59  *               public void modifyText(ModifyEvent e) {
60  *                   Text text = (Text)editor.getEditor();
61  *                   editor.getItem().setText(text.getText());
62  *               }
63  *           });
64  *           newEditor.selectAll();
65  *           newEditor.setFocus();
66  *           editor.setEditor(newEditor, item);
67  *       }
68  *   });
69  * </pre></code>
70  */
71  public class TreeEditor extends ControlEditor { 
72      Tree tree;
73      TreeItem item;
74      int column = 0;
75      ControlListener columnListener;
76      TreeListener treeListener;
77      Runnable   timer;
78      static final int TIMEOUT = 1500;
79      
80  /**
81  * Creates a TreeEditor for the specified Tree.
82  *
83  * @param tree the Tree Control above which this editor will be displayed
84  *
85  */
86  public TreeEditor (Tree tree) {
87      super(tree);
88      this.tree = tree;
89  
90      columnListener = new ControlListener() {
91          public void controlMoved(ControlEvent e){
92              layout();
93          }
94          public void controlResized(ControlEvent e){
95              layout();
96          }
97      };
98      timer = new Runnable   () {
99          public void run() {
100             layout ();
101         }
102     };
103     treeListener = new TreeListener () {
104         final Runnable   runnable = new Runnable  () {
105             public void run() {
106                 if (editor == null || editor.isDisposed()) return;
107                 if (TreeEditor.this.tree.isDisposed()) return;
108                 layout();
109                 editor.setVisible(true);
110             }
111         };
112         public void treeCollapsed(TreeEvent e) {
113             if (editor == null || editor.isDisposed ()) return;
114             editor.setVisible(false);
115             e.display.asyncExec(runnable);
116         }
117         public void treeExpanded(TreeEvent e) {
118             if (editor == null || editor.isDisposed ()) return;
119             editor.setVisible(false);
120             e.display.asyncExec(runnable);
121         }
122     };
123     tree.addTreeListener(treeListener);
124     
125     // To be consistent with older versions of SWT, grabVertical defaults to true
126     grabVertical = true;
127 }
128 
129 Rectangle computeBounds () {
130     if (item == null || column == -1 || item.isDisposed()) return new Rectangle(0, 0, 0, 0);
131     Rectangle cell = item.getBounds(column);
132     Rectangle rect = item.getImageBounds(column);
133     cell.x = rect.x + rect.width;
134     cell.width -= rect.width;
135     Rectangle area = tree.getClientArea();
136     if (cell.x < area.x + area.width) {
137         if (cell.x + cell.width > area.x + area.width) {
138             cell.width = area.x + area.width - cell.x;
139         }
140     }
141     Rectangle editorRect = new Rectangle(cell.x, cell.y, minimumWidth, minimumHeight);
142 
143     if (grabHorizontal) {
144         if (tree.getColumnCount() == 0) {
145             // Bounds of tree item only include the text area - stretch out to include 
146             // entire client area
147             cell.width = area.x + area.width - cell.x;
148         }
149         editorRect.width = Math.max(cell.width, minimumWidth);
150     }
151     
152     if (grabVertical) {
153         editorRect.height = Math.max(cell.height, minimumHeight);
154     }
155     
156     if (horizontalAlignment == SWT.RIGHT) {
157         editorRect.x += cell.width - editorRect.width;
158     } else if (horizontalAlignment == SWT.LEFT) {
159         // do nothing - cell.x is the right answer
160     } else { // default is CENTER
161         editorRect.x += (cell.width - editorRect.width)/2;
162     }
163     // don't let the editor overlap with the +/- of the tree
164     editorRect.x = Math.max(cell.x, editorRect.x);
165     
166     if (verticalAlignment == SWT.BOTTOM) {
167         editorRect.y += cell.height - editorRect.height;
168     } else if (verticalAlignment == SWT.TOP) {
169         // do nothing - cell.y is the right answer
170     } else { // default is CENTER
171         editorRect.y += (cell.height - editorRect.height)/2;
172     }
173     return editorRect;
174 }
175 
176 /**
177  * Removes all associations between the TreeEditor and the row in the tree.  The
178  * tree and the editor Control are <b>not</b> disposed.
179  */
180 public void dispose () {
181     if (tree != null && !tree.isDisposed()) {
182         if (this.column > -1 && this.column < tree.getColumnCount()){
183             TreeColumn treeColumn = tree.getColumn(this.column);
184             treeColumn.removeControlListener(columnListener);
185         }
186         if (treeListener != null) tree.removeTreeListener(treeListener);
187     }
188     columnListener = null;
189     treeListener = null;
190     tree = null;
191     item = null;
192     column = 0;
193     timer = null;
194     super.dispose();
195 }
196 
197 /**
198 * Returns the zero based index of the column of the cell being tracked by this editor.
199 *
200 * @return the zero based index of the column of the cell being tracked by this editor
201 *
202 * @since 3.1
203 */
204 public int getColumn () {
205     return column;
206 }
207 
208 /**
209 * Returns the TreeItem for the row of the cell being tracked by this editor.
210 *
211 * @return the TreeItem for the row of the cell being tracked by this editor
212 */
213 public TreeItem getItem () {
214     return item;
215 }
216 
217 void resize () {
218     layout();
219     /*
220      * On some platforms, the table scrolls when an item that
221      * is partially visible at the bottom of the table is
222      * selected.  Ensure that the correct row is edited by
223      * laying out one more time in a timerExec().
224      */
225     if (tree != null) {
226         Display display = tree.getDisplay();
227         display.timerExec(-1, timer);
228         display.timerExec(TIMEOUT, timer);
229     }
230 }
231 
232 /**
233 * Sets the zero based index of the column of the cell being tracked by this editor.
234 * 
235 * @param column the zero based index of the column of the cell being tracked by this editor
236 *
237 * @since 3.1
238 */
239 public void setColumn(int column) {
240     int columnCount = tree.getColumnCount();
241     // Separately handle the case where the tree has no TreeColumns.
242     // In this situation, there is a single default column.
243     if (columnCount == 0) {
244         this.column = (column == 0) ? 0 : -1;
245         resize();
246         return;
247     }
248     if (this.column > -1 && this.column < columnCount){
249         TreeColumn treeColumn = tree.getColumn(this.column);
250         treeColumn.removeControlListener(columnListener);
251         this.column = -1;
252     }
253 
254     if (column < 0  || column >= tree.getColumnCount()) return; 
255         
256     this.column = column;
257     TreeColumn treeColumn = tree.getColumn(this.column);
258     treeColumn.addControlListener(columnListener);
259     resize();
260 }
261 
262 public void setItem (TreeItem item) {
263     this.item = item;
264     resize();
265 }
266 
267 /**
268 * Specify the Control that is to be displayed and the cell in the tree that it is to be positioned above.
269 *
270 * <p>Note: The Control provided as the editor <b>must</b> be created with its parent being the Tree control
271 * specified in the TreeEditor constructor.
272 * 
273 * @param editor the Control that is displayed above the cell being edited
274 * @param item the TreeItem for the row of the cell being tracked by this editor
275 * @param column the zero based index of the column of the cell being tracked by this editor
276 *
277 * @since 3.1
278 */
279 public void setEditor (Control editor, TreeItem item, int column) {
280     setItem(item);
281     setColumn(column);
282     setEditor(editor);
283 }
284 public void setEditor (Control editor) {
285     super.setEditor(editor);
286     resize();
287 }
288 
289 /**
290 * Specify the Control that is to be displayed and the cell in the tree that it is to be positioned above.
291 *
292 * <p>Note: The Control provided as the editor <b>must</b> be created with its parent being the Tree control
293 * specified in the TreeEditor constructor.
294 * 
295 * @param editor the Control that is displayed above the cell being edited
296 * @param item the TreeItem for the row of the cell being tracked by this editor
297 */
298 public void setEditor (Control editor, TreeItem item) {
299     setItem(item);
300     setEditor(editor);
301 }
302 
303 public void layout () {
304     if (tree == null || tree.isDisposed()) return;
305     if (item == null || item.isDisposed()) return;  
306     int columnCount = tree.getColumnCount();
307     if (columnCount == 0 && column != 0) return;
308     if (columnCount > 0 && (column < 0 || column >= columnCount)) return;
309     super.layout();
310 }
311 }
312
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