Java tutorial
/* * Copyright (c) 2010, 2017, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package javafx.scene.control; import javafx.beans.property.BooleanProperty; import javafx.beans.property.BooleanPropertyBase; import javafx.scene.Node; /** * <p> * A {@link MenuItem} that can be toggled between selected and unselected states. * It is intended that CheckMenuItem be used in conjunction with the * {@link Menu} or {@link ContextMenu} controls. * <p> * Creating and inserting a CheckMenuItem into a Menu is shown below. <pre><code> final subsystem1 = new CheckMenuItem("Enabled"); subsystem1.setOnAction(new EventHandler<ActionEvent>() { public void handle(ActionEvent e) { System.out.println("subsystem1 #1 Enabled!"); } }); Menu subsystemsMenu = new Menu("Subsystems"); subsystemsMenu.add(subsystem1); </code></pre> * <p> * Of course, the approach shown above separates out the definition of the * CheckMenuItem from the Menu, but this needn't be so. * <p> * To ascertain the current state of the CheckMenuItem, you should refer to the * {@link #selectedProperty() selected} boolean. An example use case may be the following example: <pre><code> final checkMenuItem = new CheckMenuItem("Show Widget"); subsystem1.setOnAction(new EventHandler<ActionEvent>() { public void handle(ActionEvent e) { System.out.println("Show the widget!"); } }); private final BooleanProperty widgetShowing(); public final boolean isWidgetShowing() { return widgetShowing.get(); ) public final void setWidgetShowing(boolean value) { widgetShowingProperty().set(value); } public final BooleanProperty widgetShowingProperty() { if (widgetShowing == null) { widgetShowing = new SimpleBooleanProperty(this, "widgetShowing", true); } return widgetShowing; } widgetShowing.bind(checkMenuItem.selected); </code></pre> * <p> * Typically a CheckMenuItem will be rendered such that, when selected, it shows * a check (or tick) mark in the area normally reserved for the MenuItem * graphic. Of course, this will vary depending on the skin and styling specified. * * @see Menu * @see MenuItem * @see RadioMenuItem * * @since JavaFX 2.0 */ public class CheckMenuItem extends MenuItem { /*************************************************************************** * * * Constructors * * * **************************************************************************/ public CheckMenuItem() { this(null, null); } /** * Constructs a CheckMenuItem and sets the display text with the specified text. * @param text the display text */ public CheckMenuItem(String text) { this(text, null); } /** * Constructs a CheckMenuItem and sets the display text with the specified text * and sets the graphic {@link Node} to the given node. * @param text the display text * @param graphic the graphic Node */ public CheckMenuItem(String text, Node graphic) { super(text, graphic); getStyleClass().add(DEFAULT_STYLE_CLASS); } /*************************************************************************** * * * Properties * * * **************************************************************************/ /** * Represents the current state of this CheckMenuItem. Bind to this to be * informed whenever the user interacts with the CheckMenuItem (and causes the * selected state to be toggled). * * @defaultValue false */ private BooleanProperty selected; public final void setSelected(boolean value) { selectedProperty().set(value); } public final boolean isSelected() { return selected == null ? false : selected.get(); } public final BooleanProperty selectedProperty() { if (selected == null) { selected = new BooleanPropertyBase() { @Override protected void invalidated() { // force validation get(); // update the styleclass if (isSelected()) { getStyleClass().add(STYLE_CLASS_SELECTED); } else { getStyleClass().remove(STYLE_CLASS_SELECTED); } } @Override public Object getBean() { return CheckMenuItem.this; } @Override public String getName() { return "selected"; } }; } return selected; } /*************************************************************************** * * * Stylesheet Handling * * * **************************************************************************/ private static final String DEFAULT_STYLE_CLASS = "check-menu-item"; private static final String STYLE_CLASS_SELECTED = "selected"; }