PopupList


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  import org.eclipse.swt.*;
14  import org.eclipse.swt.events.*;
15  import org.eclipse.swt.graphics.*;
16  import org.eclipse.swt.widgets.*;
17  /**
18  * A PopupList is a list of selectable items that appears in its own shell positioned above
19  * its parent shell.  It is used for selecting items when editing a Table cell (similar to the
20  * list that appears when you open a Combo box).
21  *
22  * The list will be positioned so that it does not run off the screen and the largest number of items
23  * are visible.  It may appear above the current cursor location or below it depending how close you 
24  * are to the edge of the screen.
25  */
26  public class PopupList {
27      Shell  shell;
28      List   list;
29      int    minimumWidth;
30  /** 
31  * Creates a PopupList above the specified shell.
32  * 
33  * @param parent a Shell control which will be the parent of the new instance (cannot be null)
34  */
35  public PopupList(Shell parent) {
36      this (parent, 0);
37  }
38  /** 
39  * Creates a PopupList above the specified shell.
40  * 
41  * @param parent a widget which will be the parent of the new instance (cannot be null)
42  * @param style the style of widget to construct
43  * 
44  * @since 3.0 
45  */
46  public PopupList(Shell parent, int style) {
47      shell = new Shell(parent, checkStyle(style));
48      
49      list = new List(shell, SWT.SINGLE | SWT.V_SCROLL);  
50  
51      // close dialog if user selects outside of the shell
52      shell.addListener(SWT.Deactivate, new Listener() {
53          public void handleEvent(Event e){   
54              shell.setVisible (false);
55          }
56      });
57      
58      // resize shell when list resizes
59      shell.addControlListener(new ControlListener() {
60          public void controlMoved(ControlEvent e){}
61          public void controlResized(ControlEvent e){
62              Rectangle shellSize = shell.getClientArea();
63              list.setSize(shellSize.width, shellSize.height);
64          }
65      });
66      
67      // return list selection on Mouse Up or Carriage Return
68      list.addMouseListener(new MouseListener() {
69          public void mouseDoubleClick(MouseEvent e){}
70          public void mouseDown(MouseEvent e){}
71          public void mouseUp(MouseEvent e){
72              shell.setVisible (false);
73          }
74      });
75      list.addKeyListener(new KeyListener() {
76          public void keyReleased(KeyEvent e){}
77          public void keyPressed(KeyEvent e){
78              if (e.character == '\r'){
79                  shell.setVisible (false);
80              }
81          }
82      });
83      
84  }
85  private static int checkStyle (int style) {
86      int mask = SWT.LEFT_TO_RIGHT | SWT.RIGHT_TO_LEFT;
87      return style & mask;
88  }
89  /**
90  * Gets the widget font.
91  * <p>
92  * @return the widget font
93  *
94  * @exception SWTException <ul>
95  *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
96  *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
97  *   </ul>
98  */
99  public Font getFont () {
100     return list.getFont();
101 }
102 /**
103 * Gets the items.
104 * <p>
105 * This operation will fail if the items cannot
106 * be queried from the OS.
107 *
108 * @return the items in the widget
109 *
110 * @exception SWTException <ul>
111 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
112 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
113 *   </ul>
114 */
115 public String  [] getItems () {
116     return list.getItems();
117 }
118 /**
119 * Gets the minimum width of the list.
120 *
121 * @return the minimum width of the list
122 */
123 public int getMinimumWidth () {
124     return minimumWidth;
125 }
126 /**
127 * Launches the Popup List, waits for an item to be selected and then closes the PopupList.
128 *
129 * @param rect the initial size and location of the PopupList; the dialog will be
130 *        positioned so that it does not run off the screen and the largest number of items are visible
131 *
132 * @return the text of the selected item or null if no item is selected
133 */
134 public String   open (Rectangle rect) {
135 
136     Point listSize = list.computeSize (rect.width, SWT.DEFAULT, false);
137     Rectangle screenSize = shell.getDisplay().getBounds();
138 
139     // Position the dialog so that it does not run off the screen and the largest number of items are visible
140     int spaceBelow = screenSize.height - (rect.y + rect.height) - 30;
141     int spaceAbove = rect.y - 30;
142 
143     int y = 0;
144     if (spaceAbove > spaceBelow && listSize.y > spaceBelow) {
145         // place popup list above table cell
146         if (listSize.y > spaceAbove){
147             listSize.y = spaceAbove;
148         } else {
149             listSize.y += 2;
150         }
151         y = rect.y - listSize.y;
152         
153     } else {
154         // place popup list below table cell
155         if (listSize.y > spaceBelow){
156             listSize.y = spaceBelow;
157         } else {
158             listSize.y += 2;
159         }
160         y = rect.y + rect.height;
161     }
162     
163     // Make dialog as wide as the cell
164     listSize.x = rect.width;
165     // dialog width should not be less than minimumWidth
166     if (listSize.x < minimumWidth)
167         listSize.x = minimumWidth;
168     
169     // Align right side of dialog with right side of cell
170     int x = rect.x + rect.width - listSize.x;
171     
172     shell.setBounds(x, y, listSize.x, listSize.y);
173     
174     shell.open();
175     list.setFocus();
176 
177     Display display = shell.getDisplay();
178     while (!shell.isDisposed () && shell.isVisible ()) {
179         if (!display.readAndDispatch()) display.sleep();
180     }
181     
182     String   result = null;
183     if (!shell.isDisposed ()) {
184         String   [] strings = list.getSelection ();
185         shell.dispose();
186         if (strings.length != 0) result = strings [0];
187     }
188     return result;
189 }
190 /**
191 * Selects an item with text that starts with specified String.
192 * <p>
193 * If the item is not currently selected, it is selected.  
194 * If the item at an index is selected, it remains selected.  
195 * If the string is not matched, it is ignored.
196 *
197 * @param string the text of the item
198 *
199 * @exception SWTException <ul>
200 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
201 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
202 *   </ul>
203 */
204 public void select(String   string) {
205     String  [] items = list.getItems();
206 
207     // find the first entry in the list that starts with the
208     // specified string
209     if (string != null){
210         for (int i = 0; i < items.length; i++) {
211             if (items[i].startsWith(string)){
212                 int index = list.indexOf(items[i]);
213                 list.select(index);
214                 break;
215             }
216         }
217     }
218 }
219 /**
220 * Sets the widget font.
221 * <p>
222 * When new font is null, the font reverts
223 * to the default system font for the widget.
224 *
225 * @param font the new font (or null)
226 * 
227 * @exception SWTException <ul>
228 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
229 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
230 *   </ul>
231 */
232 public void setFont (Font font) {
233     list.setFont(font);
234 }
235 /**
236 * Sets all items.
237 * <p>
238 * The previous selection is cleared.
239 * The previous items are deleted.
240 * The new items are added.
241 * The top index is set to 0.
242 *
243 * @param strings the array of items
244 *
245 * This operation will fail when an item is null
246 * or could not be added in the OS.
247 * 
248 * @exception IllegalArgumentException <ul>
249 *    <li>ERROR_NULL_ARGUMENT - if the items array is null</li>
250 *    <li>ERROR_INVALID_ARGUMENT - if an item in the items array is null</li>
251 * </ul>
252 * @exception SWTException <ul>
253 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
254 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
255 *   </ul>
256 */
257 public void setItems (String  [] strings) {
258     list.setItems(strings);
259 }
260 /**
261 * Sets the minimum width of the list.
262 *
263 * @param width the minimum width of the list
264 */
265 public void setMinimumWidth (int width) {
266     if (width < 0)
267         SWT.error(SWT.ERROR_INVALID_ARGUMENT);
268         
269     minimumWidth = width;
270 }
271 }
272
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