ch.sebastienzurfluh.swissmuseum.parcours.client.view.bookletnavigator.InteractiveCarousel.java Source code

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Here is the source code for ch.sebastienzurfluh.swissmuseum.parcours.client.view.bookletnavigator.InteractiveCarousel.java

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/*
 * Copyright 2012-2013 Sebastien Zurfluh
 * 
 * This file is part of "Parcours".
 * 
 * "Parcours" is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * 
 * "Parcours" 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 for more details.
 * 
 *  You should have received a copy of the GNU General Public License
 *  along with "Parcours".  If not, see <http://www.gnu.org/licenses/>.
 */

package ch.sebastienzurfluh.swissmuseum.parcours.client.view.bookletnavigator;

import ch.sebastienzurfluh.swissmuseum.core.client.control.eventbus.EventBus;
import ch.sebastienzurfluh.swissmuseum.core.client.control.eventbus.events.PageChangeRequest;
import ch.sebastienzurfluh.swissmuseum.core.client.model.Model;
import ch.sebastienzurfluh.swissmuseum.core.client.model.structure.DataReference;
import ch.sebastienzurfluh.swissmuseum.core.client.model.structure.MenuData;
import ch.sebastienzurfluh.swissmuseum.parcours.client.control.TimeMachine;

import com.google.gwt.event.logical.shared.SelectionEvent;
import com.google.gwt.event.logical.shared.SelectionHandler;
import com.google.gwt.user.client.Command;
import com.google.gwt.user.client.ui.Widget;
import com.googlecode.mgwt.ui.client.widget.Carousel;

/** This extended {@link Carousel} sends notifications through {@link EventBus} when a page is 
 * turned.
 *
 * @author Sebastien Zurfluh
 *
 */
public class InteractiveCarousel extends Carousel {
    private int widgetCount = 0;

    public InteractiveCarousel(final EventBus eventBus, final Model model) {
        super();
        widgetCount = 0;

        addSelectionHandler(new SelectionHandler<Integer>() {
            int previousSelection = -1;

            @Override
            public void onSelection(SelectionEvent<Integer> event) {
                if (previousSelection == -1) {
                    previousSelection = event.getSelectedItem();
                    deferedSetSelectedPage(1);
                } else {
                    if ((event.getSelectedItem() == 0 || event.getSelectedItem() == widgetCount - 1)) {
                        previousSelection = -1;
                        eventBus.fireEvent(new PageChangeRequest(DataReference.SUPER));
                    } else if (previousSelection < event.getSelectedItem()) {
                        previousSelection = event.getSelectedItem();

                        // WORKAROUND
                        // get the next page reference (without using the model's dedicated method
                        int i = 0;
                        for (MenuData menuData : model.getAllPageMenusInCurrentGroup()) {
                            if (i == event.getSelectedItem()) {
                                eventBus.fireEvent(new PageChangeRequest(menuData.getReference()));
                                break;
                            }
                            i++;
                        }
                        // END OF WORKAROUND
                    } else if (previousSelection > event.getSelectedItem()) {
                        previousSelection = event.getSelectedItem();
                        eventBus.fireEvent(new PageChangeRequest(model.getPreviousPageMenu().getReference()));
                    }
                }
            }
        });
    }

    private boolean isDeferedSetSelectedPage = false;
    private int deferedSelectedPage = 1;

    /**
     * We may need to defer the selection of the page until the carousel is properly loaded.
     * @param index the index of the page we want to load.
     */
    private void deferedSetSelectedPage(final int index) {
        if (widgetCount > index) {
            isDeferedSetSelectedPage = false;
            setSelectedPage(index);
        } else {
            isDeferedSetSelectedPage = true;
            deferedSelectedPage = index;
        }
    }

    @Override
    public void add(Widget w) {
        super.add(w);
        widgetCount++;
        if (isDeferedSetSelectedPage) {
            deferedSetSelectedPage(deferedSelectedPage);
        }
    }

    @Override
    public void clear() {
        super.clear();
        widgetCount = 0;
        isDeferedSetSelectedPage = false;
    }
}