com.google.gwt.sample.kitchensink.client.Trees.java Source code

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Here is the source code for com.google.gwt.sample.kitchensink.client.Trees.java

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/*
 * Copyright 2006 Google Inc.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */
package com.google.gwt.sample.kitchensink.client;

import com.google.gwt.user.client.ui.Tree;
import com.google.gwt.user.client.ui.TreeItem;
import com.google.gwt.user.client.ui.TreeListener;

/**
 * Demonstrates the {@link com.google.gwt.user.client.ui.Tree} widget.
 */
public class Trees extends Sink implements TreeListener {

    private static class PendingItem extends TreeItem {
        public PendingItem() {
            super("Please wait...");
        }
    }

    private static class Proto {
        public Proto[] children;
        public TreeItem item;
        public String text;

        public Proto(String text) {
            this.text = text;
        }

        public Proto(String text, Proto[] children) {
            this(text);
            this.children = children;
        }
    }

    private static Proto[] fProto = new Proto[] {
            new Proto("Beethoven", new Proto[] {
                    new Proto("Concertos",
                            new Proto[] { new Proto("No. 1 - C"), new Proto("No. 2 - B-Flat Major"),
                                    new Proto("No. 3 - C Minor"), new Proto("No. 4 - G Major"),
                                    new Proto("No. 5 - E-Flat Major"), }),
                    new Proto(
                            "Quartets",
                            new Proto[] {
                                    new Proto("Six String Quartets"), new Proto("Three String Quartets"),
                                    new Proto("Grosse Fugue for String Quartets"), }),
                    new Proto("Sonatas",
                            new Proto[] { new Proto("Sonata in A Minor"), new Proto("Sonata in F Major"), }),
                    new Proto("Symphonies",
                            new Proto[] { new Proto("No. 1 - C Major"), new Proto("No. 2 - D Major"),
                                    new Proto("No. 3 - E-Flat Major"), new Proto("No. 4 - B-Flat Major"),
                                    new Proto("No. 5 - C Minor"), new Proto("No. 6 - F Major"),
                                    new Proto("No. 7 - A Major"), new Proto("No. 8 - F Major"),
                                    new Proto("No. 9 - D Minor"), }), }),
            new Proto("Brahms", new Proto[] {
                    new Proto("Concertos",
                            new Proto[] { new Proto("Violin Concerto"), new Proto("Double Concerto - A Minor"),
                                    new Proto("Piano Concerto No. 1 - D Minor"),
                                    new Proto("Piano Concerto No. 2 - B-Flat Major"), }),
                    new Proto("Quartets", new Proto[] { new Proto("Piano Quartet No. 1 - G Minor"),
                            new Proto("Piano Quartet No. 2 - A Major"), new Proto("Piano Quartet No. 3 - C Minor"),
                            new Proto("String Quartet No. 3 - B-Flat Minor"), }),
                    new Proto("Sonatas",
                            new Proto[] { new Proto("Two Sonatas for Clarinet - F Minor"),
                                    new Proto("Two Sonatas for Clarinet - E-Flat Major"), }),
                    new Proto("Symphonies",
                            new Proto[] { new Proto("No. 1 - C Minor"), new Proto("No. 2 - D Minor"),
                                    new Proto("No. 3 - F Major"), new Proto("No. 4 - E Minor"), }), }),
            new Proto("Mozart",
                    new Proto[] { new Proto("Concertos",
                            new Proto[] { new Proto("Piano Concerto No. 12"), new Proto("Piano Concerto No. 17"),
                                    new Proto("Clarinet Concerto"), new Proto("Violin Concerto No. 5"),
                                    new Proto("Violin Concerto No. 4"), }), }), };

    public static SinkInfo init() {
        return new SinkInfo("Trees", "GWT has a built-in <code>Tree</code> widget.  "
                + "The tree is focusable and has keyboard support as well.") {
            public Sink createInstance() {
                return new Trees();
            }
        };
    }

    private Tree fTree = new Tree();

    public Trees() {
        for (int i = 0; i < fProto.length; ++i) {
            createItem(fProto[i]);
            fTree.addItem(fProto[i].item);
        }

        fTree.addTreeListener(this);
        initWidget(fTree);
    }

    public void onShow() {
    }

    public void onTreeItemSelected(TreeItem item) {
    }

    public void onTreeItemStateChanged(TreeItem item) {
        TreeItem child = item.getChild(0);
        if (child instanceof PendingItem) {
            item.removeItem(child);

            Proto proto = (Proto) item.getUserObject();
            for (int i = 0; i < proto.children.length; ++i) {
                createItem(proto.children[i]);
                item.addItem(proto.children[i].item);
            }
        }
    }

    private void createItem(Proto proto) {
        proto.item = new TreeItem(proto.text);
        proto.item.setUserObject(proto);
        if (proto.children != null)
            proto.item.addItem(new PendingItem());
    }
}