com.pronoiahealth.olhie.client.widgets.scrolldiv.ScrollDiv.java Source code

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Here is the source code for com.pronoiahealth.olhie.client.widgets.scrolldiv.ScrollDiv.java

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/*******************************************************************************
 * Copyright (c) 2013 Pronoia Health LLC.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     Pronoia Health LLC - initial API and implementation
 *******************************************************************************/
package com.pronoiahealth.olhie.client.widgets.scrolldiv;

import static com.google.gwt.query.client.GQuery.$;

import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;

import org.jboss.errai.ui.shared.api.annotations.DataField;
import org.jboss.errai.ui.shared.api.annotations.Templated;

import com.google.gwt.dom.client.Style.Overflow;
import com.google.gwt.query.client.Function;
import com.google.gwt.query.client.GQuery;
import com.google.gwt.query.client.Properties;
import com.google.gwt.query.client.css.CSS;
import com.google.gwt.user.client.DOM;
import com.google.gwt.user.client.Element;
import com.google.gwt.user.client.Event;
import com.google.gwt.user.client.ui.Composite;

/**
 * ScrollDiv.java<br/>
 * Responsibilities:<br/>
 * 1.
 * 
 * @author John DeStefano
 * @version 1.0
 * @since Oct 21, 2013
 * 
 */
@Templated("#root")
public class ScrollDiv extends Composite {

    @DataField("root")
    private Element root = DOM.createDiv();

    private GQuery scrollLink;

    /**
     * Constructor
     * 
     */
    public ScrollDiv() {
    }

    /**
     * Access to the root element
     * 
     * @return
     */
    public Element getRootElement() {
        return root;
    }

    @PostConstruct
    protected void postConstruct() {
        // Activate full page scrolling
        // Get the root div
        final GQuery gObj = $(root);

        // Make sure its overflow is set to auto
        gObj.css(CSS.OVERFLOW.with(Overflow.AUTO));

        // Create the scroll link
        scrollLink = $("<a href=\"#\" class=\"ph-BulletinBoard-Scrollup\">Scroll</a>");

        // Append the link to the root div
        gObj.append(scrollLink);

        // Bind the scroll event
        gObj.bind(Event.ONSCROLL, new Function() {
            @Override
            public boolean f(Event e) {
                GQuery rootDiv = $(e);
                int scrollTop = rootDiv.scrollTop();
                if (scrollTop > 100) {
                    scrollLink.fadeIn(500, new Function() {
                        @Override
                        public void f(com.google.gwt.dom.client.Element e) {
                            $(e).css(Properties.create("opacity: 1.0;"));
                            // super.f(e);
                        }
                    });
                } else {
                    scrollLink.fadeOut(500, new Function() {
                        @Override
                        public void f(com.google.gwt.dom.client.Element e) {
                            $(e).css(Properties.create("opacity: 0.0;"));
                            // super.f(e);
                        }
                    });
                }
                return super.f(e);
            }
        });

        // Bind to the scrollup link
        scrollLink.bind(Event.ONCLICK, new Function() {
            @Override
            public boolean f(Event e) {
                gObj.animate("scrollTop: 0", 500, (Function) null);
                return false;
            }
        });
    }

    @PreDestroy
    protected void preDestroy() {
        $(root).unbind(Event.ONSCROLL);
        scrollLink.unbind(Event.ONCLICK);
        scrollLink.remove();
    }

}