com.google.gwt.sample.showcase.client.content.lists.CwListBox.java Source code

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Here is the source code for com.google.gwt.sample.showcase.client.content.lists.CwListBox.java

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/*
 * Copyright 2008 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.showcase.client.content.lists;

import com.google.gwt.core.client.GWT;
import com.google.gwt.core.client.RunAsyncCallback;
import com.google.gwt.event.dom.client.ChangeEvent;
import com.google.gwt.event.dom.client.ChangeHandler;
import com.google.gwt.i18n.client.Constants;
import com.google.gwt.sample.showcase.client.ContentWidget;
import com.google.gwt.sample.showcase.client.ShowcaseAnnotations.ShowcaseData;
import com.google.gwt.sample.showcase.client.ShowcaseAnnotations.ShowcaseSource;
import com.google.gwt.sample.showcase.client.ShowcaseAnnotations.ShowcaseStyle;
import com.google.gwt.user.client.rpc.AsyncCallback;
import com.google.gwt.user.client.ui.HTML;
import com.google.gwt.user.client.ui.HorizontalPanel;
import com.google.gwt.user.client.ui.ListBox;
import com.google.gwt.user.client.ui.VerticalPanel;
import com.google.gwt.user.client.ui.Widget;

/**
 * Example file.
 */
@ShowcaseStyle(".gwt-ListBox")
public class CwListBox extends ContentWidget {
    /**
     * The constants used in this Content Widget.
     */
    @ShowcaseSource
    public static interface CwConstants extends Constants {
        String[] cwListBoxCars();

        String[] cwListBoxCategories();

        String cwListBoxDescription();

        String cwListBoxName();

        String cwListBoxSelectAll();

        String cwListBoxSelectCategory();

        String[] cwListBoxSports();

        String[] cwListBoxVacations();
    }

    /**
     * An instance of the constants.
     */
    @ShowcaseData
    private final CwConstants constants;

    /**
     * Constructor.
     *
     * @param constants the constants
     */
    public CwListBox(CwConstants constants) {
        super(constants.cwListBoxName(), constants.cwListBoxDescription(), true);
        this.constants = constants;
    }

    /**
     * Initialize this example.
     */
    @ShowcaseSource
    @Override
    public Widget onInitialize() {
        // Create a panel to align the Widgets
        HorizontalPanel hPanel = new HorizontalPanel();
        hPanel.setSpacing(20);

        // Add a drop box with the list types
        final ListBox dropBox = new ListBox(false);
        String[] listTypes = constants.cwListBoxCategories();
        for (int i = 0; i < listTypes.length; i++) {
            dropBox.addItem(listTypes[i]);
        }
        dropBox.ensureDebugId("cwListBox-dropBox");
        VerticalPanel dropBoxPanel = new VerticalPanel();
        dropBoxPanel.setSpacing(4);
        dropBoxPanel.add(new HTML(constants.cwListBoxSelectCategory()));
        dropBoxPanel.add(dropBox);
        hPanel.add(dropBoxPanel);

        // Add a list box with multiple selection enabled
        final ListBox multiBox = new ListBox(true);
        multiBox.ensureDebugId("cwListBox-multiBox");
        multiBox.setWidth("11em");
        multiBox.setVisibleItemCount(10);
        VerticalPanel multiBoxPanel = new VerticalPanel();
        multiBoxPanel.setSpacing(4);
        multiBoxPanel.add(new HTML(constants.cwListBoxSelectAll()));
        multiBoxPanel.add(multiBox);
        hPanel.add(multiBoxPanel);

        // Add a handler to handle drop box events
        dropBox.addChangeHandler(new ChangeHandler() {
            public void onChange(ChangeEvent event) {
                showCategory(multiBox, dropBox.getSelectedIndex());
                multiBox.ensureDebugId("cwListBox-multiBox");
            }
        });

        // Show default category
        showCategory(multiBox, 0);
        multiBox.ensureDebugId("cwListBox-multiBox");

        // Return the panel
        return hPanel;
    }

    @Override
    protected void asyncOnInitialize(final AsyncCallback<Widget> callback) {
        GWT.runAsync(CwListBox.class, new RunAsyncCallback() {

            public void onFailure(Throwable caught) {
                callback.onFailure(caught);
            }

            public void onSuccess() {
                callback.onSuccess(onInitialize());
            }
        });
    }

    /**
     * Display the options for a given category in the list box.
     *
     * @param listBox the ListBox to add the options to
     * @param category the category index
     */
    @ShowcaseSource
    private void showCategory(ListBox listBox, int category) {
        listBox.clear();
        String[] listData = null;
        switch (category) {
        case 0:
            listData = constants.cwListBoxCars();
            break;
        case 1:
            listData = constants.cwListBoxSports();
            break;
        case 2:
            listData = constants.cwListBoxVacations();
            break;
        }
        for (int i = 0; i < listData.length; i++) {
            listBox.addItem(listData[i]);
        }
    }
}