1 /*
2 * Copyright (c) 2010, 2016, Oracle and/or its affiliates. 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. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package javafx.scene.control;
27
28 import javafx.scene.control.skin.LabelSkin;
29 import com.sun.javafx.scene.NodeHelper;
30
31 import javafx.beans.property.ObjectProperty;
32 import javafx.beans.property.ObjectPropertyBase;
33 import javafx.beans.value.ChangeListener;
34 import javafx.beans.value.WritableValue;
35 import javafx.css.StyleableProperty;
36 import javafx.scene.AccessibleRole;
37 import javafx.scene.Node;
38
39 /**
40 * Label is a non-editable text control. A Label is useful for displaying
41 * text that is required to fit within a specific space, and thus may need
42 * to use an ellipsis or truncation to size the string to fit. Labels also are
43 * useful in that they can have mnemonics which, if used, will send focus to
44 * the Control listed as the target of the <code>labelFor</code> property.
45 * <p>
46 * Label sets focusTraversable to false.
47 * </p>
48 *
49 * <p>Example:
50 * <pre><code>Label label = new Label("a label");</code></pre>
51 * @since JavaFX 2.0
52 */
53 public class Label extends Labeled {
54
55 /***************************************************************************
56 * *
57 * Constructors *
58 * *
59 **************************************************************************/
60
61 /**
62 * Creates an empty label
63 */
64 public Label() {
65 initialize();
66 }
67
68 /**
69 * Creates Label with supplied text.
70 * @param text null text is treated as the empty string
71 */
72 public Label(String text) {
73 super(text);
74 initialize();
75 }
76
77 /**
78 * Creates a Label with the supplied text and graphic.
79 * @param text null text is treated as the empty string
80 * @param graphic a null graphic is acceptable
81 */
82 public Label(String text, Node graphic) {
83 super(text, graphic);
84 initialize();
85 }
86
87 private void initialize() {
88 getStyleClass().setAll("label");
89 setAccessibleRole(AccessibleRole.TEXT);
90 // Labels are not focus traversable, unlike most other UI Controls.
91 // focusTraversable is styleable through css. Calling setFocusTraversable
92 // makes it look to css like the user set the value and css will not
93 // override. Initializing focusTraversable by calling set on the
94 // CssMetaData ensures that css will be able to override the value.
95 ((StyleableProperty<Boolean>)(WritableValue<Boolean>)focusTraversableProperty()).applyStyle(null, Boolean.FALSE);
96 }
97
98 /***************************************************************************
99 * *
100 * Properties *
101 * *
102 **************************************************************************/
103
104 private ChangeListener<Boolean> mnemonicStateListener = (observable, oldValue, newValue) -> {
105 NodeHelper.showMnemonicsProperty(Label.this).setValue(newValue);
106 };
107
108 /**
109 * A Label can act as a label for a different Control or
110 * Node. This is used for Mnemonics and Accelerator parsing.
111 * This allows setting of the target Node.
112 * @return the label for this node
113 */
114 public ObjectProperty<Node> labelForProperty() {
115 if (labelFor == null) {
116 labelFor = new ObjectPropertyBase<Node>() {
117 Node oldValue = null;
118 @Override protected void invalidated() {
119 if (oldValue != null) {
120 NodeHelper.getNodeAccessor().setLabeledBy(oldValue, null);
121 NodeHelper.showMnemonicsProperty(oldValue).removeListener(mnemonicStateListener);
122 }
123 final Node node = get();
124 if (node != null) {
125 NodeHelper.getNodeAccessor().setLabeledBy(node, Label.this);
126 NodeHelper.showMnemonicsProperty(node).addListener(mnemonicStateListener);
127 NodeHelper.setShowMnemonics(Label.this, NodeHelper.isShowMnemonics(node));
128 } else {
129 NodeHelper.setShowMnemonics(Label.this, false);
130 }
131 oldValue = node;
132 }
133
134 @Override public Object getBean() {
135 return Label.this;
136 }
137
138 @Override public String getName() {
139 return "labelFor";
140 }
141 };
142
143 }
144 return labelFor;
145 }
146 private ObjectProperty<Node> labelFor;
147
148 public final void setLabelFor(Node value) { labelForProperty().setValue(value); }
149 public final Node getLabelFor() { return labelFor == null ? null : labelFor.getValue(); }
150
151 /***************************************************************************
152 * *
153 * Methods *
154 * *
155 **************************************************************************/
156
157 /** {@inheritDoc} */
158 @Override protected Skin<?> createDefaultSkin() {
159 return new LabelSkin(this);
160 }
161
162 /***************************************************************************
163 * *
164 * CSS Support *
165 * *
166 **************************************************************************/
167
168 /**
169 * Returns the initial focus traversable state of this control, for use
170 * by the JavaFX CSS engine to correctly set its initial value. This method
171 * is overridden as by default UI controls have focus traversable set to true,
172 * but that is not appropriate for this control.
173 *
174 * @since 9
175 */
176 @Override protected Boolean getInitialFocusTraversable() {
177 return Boolean.FALSE;
178 }
179
180 }