1 /*
2 * Copyright 1997-2005 Sun Microsystems, Inc. All Rights Reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Sun designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Sun in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
22 * CA 95054 USA or visit www.sun.com if you need additional information or
23 * have any questions.
24 */
25
26 package javax.swing;
27
28 import java.awt.Component;
29
30
31 /**
32 * Identifies components that can be used as "rubber stamps" to paint
33 * the cells in a JList. For example, to use a JLabel as a
34 * ListCellRenderer, you would write something like this:
35 * <pre>
36 * class MyCellRenderer extends JLabel implements ListCellRenderer {
37 * public MyCellRenderer() {
38 * setOpaque(true);
39 * }
40 *
41 * public Component getListCellRendererComponent(JList list,
42 * Object value,
43 * int index,
44 * boolean isSelected,
45 * boolean cellHasFocus) {
46 *
47 * setText(value.toString());
48 *
49 * Color background;
50 * Color foreground;
51 *
52 * // check if this cell represents the current DnD drop location
53 * JList.DropLocation dropLocation = list.getDropLocation();
54 * if (dropLocation != null
55 * && !dropLocation.isInsert()
56 * && dropLocation.getIndex() == index) {
57 *
58 * background = Color.BLUE;
59 * foreground = Color.WHITE;
60 *
61 * // check if this cell is selected
62 * } else if (isSelected) {
63 * background = Color.RED;
64 * foreground = Color.WHITE;
65 *
66 * // unselected, and not the DnD drop location
67 * } else {
68 * background = Color.WHITE;
69 * foreground = Color.BLACK;
70 * };
71 *
72 * setBackground(background);
73 * setForeground(foreground);
74 *
75 * return this;
76 * }
77 * }
78 * </pre>
79 *
80 * @see JList
81 * @see DefaultListCellRenderer
82 *
83 * @author Hans Muller
84 */
85 public interface ListCellRenderer
86 {
87 /**
88 * Return a component that has been configured to display the specified
89 * value. That component's <code>paint</code> method is then called to
90 * "render" the cell. If it is necessary to compute the dimensions
91 * of a list because the list cells do not have a fixed size, this method
92 * is called to generate a component on which <code>getPreferredSize</code>
93 * can be invoked.
94 *
95 * @param list The JList we're painting.
96 * @param value The value returned by list.getModel().getElementAt(index).
97 * @param index The cells index.
98 * @param isSelected True if the specified cell was selected.
99 * @param cellHasFocus True if the specified cell has the focus.
100 * @return A component whose paint() method will render the specified value.
101 *
102 * @see JList
103 * @see ListSelectionModel
104 * @see ListModel
105 */
106 Component getListCellRendererComponent(
107 JList list,
108 Object value,
109 int index,
110 boolean isSelected,
111 boolean cellHasFocus);
112 }
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