/* * 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 tree = new Tree();  public Trees() {    for (int i = 0; i < fProto.length; ++i) {      createItem(fProto[i]);      tree.addItem(fProto[i].item);    }    tree.addTreeListener(this);    initWidget(tree);  }  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());    }  }}