com.google.livingstories.client.ui.Lightbox.java Source code

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Here is the source code for com.google.livingstories.client.ui.Lightbox.java

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/**
 * Copyright 2010 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.livingstories.client.ui;

import com.google.gwt.event.dom.client.ClickEvent;
import com.google.gwt.event.dom.client.ClickHandler;
import com.google.gwt.event.logical.shared.CloseEvent;
import com.google.gwt.event.logical.shared.CloseHandler;
import com.google.gwt.event.shared.HandlerRegistration;
import com.google.gwt.user.client.DOM;
import com.google.gwt.user.client.Window;
import com.google.gwt.user.client.ui.HorizontalPanel;
import com.google.gwt.user.client.ui.Image;
import com.google.gwt.user.client.ui.Label;
import com.google.gwt.user.client.ui.PopupPanel;
import com.google.gwt.user.client.ui.VerticalPanel;
import com.google.gwt.user.client.ui.Widget;
import com.google.livingstories.client.lsp.event.EventBus;
import com.google.livingstories.client.lsp.event.PopupImageLoadedEvent;
import com.google.livingstories.client.util.Constants;
import com.google.livingstories.client.util.LivingStoryControls;

/**
 * A widget that displays content in a centered popup window, with the background dimmed.
 */
public class Lightbox extends AutoHidePopupPanel {
    private Image closeButton;
    private HandlerRegistration popupImageLoadedHandler;

    public Lightbox() {
        super(true);
        addCloseHandler(new CloseHandler<PopupPanel>() {
            @Override
            public void onClose(CloseEvent<PopupPanel> event) {
                popupImageLoadedHandler.removeHandler();
                popupImageLoadedHandler = null;
                LivingStoryControls.showGlass(false);
            }
        });

        closeButton = new Image(Constants.CLOSE_IMAGE_URL);
        closeButton.addClickHandler(new ClickHandler() {
            public void onClick(ClickEvent e) {
                hide();
            }
        });
    }

    /**
     * Show an item in the lightbox. If we have specific knowledge of the desired rendering
     * dimensions we sometimes put the contents in a scroll panel.
     * @param title the title to use
     * @param item the widget to render in the lightbox
     */
    public void showItem(String title, Widget item) {
        VerticalPanel canvas = new VerticalPanel();
        DOM.setStyleAttribute(canvas.getElement(), "padding", "10px");
        if (title != null) {
            canvas.add(createHeaderPanel(title));
        }

        canvas.add(item);

        setWidget(canvas);
        center();
        LivingStoryControls.showGlass(true);

        if (popupImageLoadedHandler != null) {
            popupImageLoadedHandler.removeHandler();
        }
        popupImageLoadedHandler = EventBus.INSTANCE.addHandler(PopupImageLoadedEvent.TYPE,
                new PopupImageLoadedEvent.Handler() {
                    public void onImageLoaded(PopupImageLoadedEvent e) {
                        center();
                    }
                });
    }

    /**
     * Reimplementation of center() that does not allow the popup to extend above or to the left
     * of the current scroll position.
     */
    @Override
    public void center() {
        setPopupPositionAndShow(new PositionCallback() {
            @Override
            public void setPosition(int offsetWidth, int offsetHeight) {
                int left = Math.max(0, (Window.getClientWidth() - getOffsetWidth()) / 2);
                int top = Math.max(0, (Window.getClientHeight() - getOffsetHeight()) / 2);
                setPopupPosition(Window.getScrollLeft() + left, Window.getScrollTop() + top);
            }
        });
    }

    @Override
    public void hide() {
        super.hide();
    }

    private Widget createHeaderPanel(String title) {
        HorizontalPanel headerPanel = new HorizontalPanel();
        headerPanel.setWidth("100%");
        headerPanel.setHorizontalAlignment(HorizontalPanel.ALIGN_LEFT);
        Label titleLabel = new Label(title);
        titleLabel.addStyleName("lightboxTitle");
        headerPanel.add(titleLabel);
        headerPanel.setHorizontalAlignment(HorizontalPanel.ALIGN_RIGHT);
        headerPanel.add(closeButton);
        return headerPanel;
    }
}