Java tutorial
/* * Copyright (c) 2014, 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 java.util.Arrays; import java.util.Collection; import java.util.Collections; import com.sun.javafx.scene.control.skin.resources.ControlResources; import javafx.application.Platform; import javafx.beans.property.ReadOnlyObjectProperty; import javafx.collections.ObservableList; import javafx.geometry.Pos; import javafx.scene.control.ButtonBar.ButtonData; import javafx.scene.layout.GridPane; import javafx.scene.layout.Priority; import javafx.scene.layout.Region; /** * A dialog that shows a list of choices to the user, from which they can pick * one item at most. * * @see Dialog * @param <T> The type of the items to show to the user, and the type that is returned * via {@link #getResult()} when the dialog is dismissed. * @since JavaFX 8u40 */ public class ChoiceDialog<T> extends Dialog<T> { /************************************************************************** * * Fields * **************************************************************************/ private final GridPane grid; private final Label label; private final ComboBox<T> comboBox; private final T defaultChoice; /************************************************************************** * * Constructors * **************************************************************************/ /** * Creates a default, empty instance of ChoiceDialog with no set items and a * null default choice. Users of this constructor will subsequently need to * call {@link #getItems()} to specify which items to show to the user. */ public ChoiceDialog() { this((T) null, (T[]) null); } /** * Creates a new ChoiceDialog instance with the first argument specifying the * default choice that should be shown to the user, and all following arguments * considered a varargs array of all available choices for the user. It is * expected that the defaultChoice be one of the elements in the choices varargs * array. If this is not true, then defaultChoice will be set to null and the * dialog will show with the initial choice set to the first item in the list * of choices. * * @param defaultChoice The item to display as the pre-selected choice in the dialog. * This item must be contained within the choices varargs array. * @param choices All possible choices to present to the user. */ public ChoiceDialog(T defaultChoice, @SuppressWarnings("unchecked") T... choices) { this(defaultChoice, choices == null ? Collections.emptyList() : Arrays.asList(choices)); } /** * Creates a new ChoiceDialog instance with the first argument specifying the * default choice that should be shown to the user, and the second argument * specifying a collection of all available choices for the user. It is * expected that the defaultChoice be one of the elements in the choices * collection. If this is not true, then defaultChoice will be set to null and the * dialog will show with the initial choice set to the first item in the list * of choices. * * @param defaultChoice The item to display as the pre-selected choice in the dialog. * This item must be contained within the choices varargs array. * @param choices All possible choices to present to the user. */ public ChoiceDialog(T defaultChoice, Collection<T> choices) { final DialogPane dialogPane = getDialogPane(); // -- grid this.grid = new GridPane(); this.grid.setHgap(10); this.grid.setMaxWidth(Double.MAX_VALUE); this.grid.setAlignment(Pos.CENTER_LEFT); // -- label label = DialogPane.createContentLabel(dialogPane.getContentText()); label.setPrefWidth(Region.USE_COMPUTED_SIZE); label.textProperty().bind(dialogPane.contentTextProperty()); dialogPane.contentTextProperty().addListener(o -> updateGrid()); setTitle(ControlResources.getString("Dialog.confirm.title")); dialogPane.setHeaderText(ControlResources.getString("Dialog.confirm.header")); dialogPane.getStyleClass().add("choice-dialog"); dialogPane.getButtonTypes().addAll(ButtonType.OK, ButtonType.CANCEL); final double MIN_WIDTH = 150; comboBox = new ComboBox<T>(); comboBox.setMinWidth(MIN_WIDTH); if (choices != null) { comboBox.getItems().addAll(choices); } comboBox.setMaxWidth(Double.MAX_VALUE); GridPane.setHgrow(comboBox, Priority.ALWAYS); GridPane.setFillWidth(comboBox, true); this.defaultChoice = comboBox.getItems().contains(defaultChoice) ? defaultChoice : null; if (defaultChoice == null) { comboBox.getSelectionModel().selectFirst(); } else { comboBox.getSelectionModel().select(defaultChoice); } updateGrid(); setResultConverter((dialogButton) -> { ButtonData data = dialogButton == null ? null : dialogButton.getButtonData(); return data == ButtonData.OK_DONE ? getSelectedItem() : null; }); } /************************************************************************** * * Public API * **************************************************************************/ /** * Returns the currently selected item in the dialog. * @return the currently selected item */ public final T getSelectedItem() { return comboBox.getSelectionModel().getSelectedItem(); } /** * Returns the property representing the currently selected item in the dialog. * @return the currently selected item property */ public final ReadOnlyObjectProperty<T> selectedItemProperty() { return comboBox.getSelectionModel().selectedItemProperty(); } /** * Sets the currently selected item in the dialog. * @param item The item to select in the dialog. */ public final void setSelectedItem(T item) { comboBox.getSelectionModel().select(item); } /** * Returns the list of all items that will be displayed to users. This list * can be modified by the developer to add, remove, or reorder the items * to present to the user. * @return the list of all items that will be displayed to users */ public final ObservableList<T> getItems() { return comboBox.getItems(); } /** * Returns the default choice that was specified in the constructor. * @return the default choice */ public final T getDefaultChoice() { return defaultChoice; } /************************************************************************** * * Private Implementation * **************************************************************************/ private void updateGrid() { grid.getChildren().clear(); grid.add(label, 0, 0); grid.add(comboBox, 1, 0); getDialogPane().setContent(grid); Platform.runLater(() -> comboBox.requestFocus()); } }