automatic load of previous feeds on scrolling done

git-svn-id: http://svn.research-infrastructures.eu/public/d4science/gcube/trunk/portlets/user/news-feed@94027 82a268e6-3cf1-43bd-a215-b396298e98cf

.settings/org.eclipse.wst.common.component

@@ -4,9 +4,6 @@
     <wb-resource deploy-path="/" source-path="/src/main/webapp" tag="defaultRootSource"/>
     <wb-resource deploy-path="/WEB-INF/classes" source-path="/src/main/java"/>
         <wb-resource deploy-path="/WEB-INF/classes" source-path="/target/generated-sources/gwt"/>
-        <dependent-module archiveName="user-selection-dialog-1.1.0-SNAPSHOT.jar" deploy-path="/WEB-INF/lib" handle="module:/resource/user-selection-dialog/user-selection-dialog">
-            <dependency-type>uses</dependency-type>
-        </dependent-module>
     <property name="java-output-path" value="/${module}/target/www/WEB-INF/classes"/>
         <property name="context-root" value="news-feed"/>
   </wb-module>

src/main/java/org/gcube/portlets/user/newsfeed/client/panels/NewsFeedPanel.java

@@ -52,10 +52,13 @@ import org.gcube.portlets.widgets.userselection.shared.ItemSelectableBean;
 import com.google.gwt.core.client.GWT;
 import com.google.gwt.core.client.RunAsyncCallback;
 import com.google.gwt.dom.client.Document;
+import com.google.gwt.dom.client.Style.Unit;
 import com.google.gwt.event.shared.HandlerManager;
 import com.google.gwt.user.client.Timer;
 import com.google.gwt.user.client.Window;
 import com.google.gwt.user.client.Window.Location;
+import com.google.gwt.user.client.Window.ScrollEvent;
+import com.google.gwt.user.client.Window.ScrollHandler;
 import com.google.gwt.user.client.rpc.AsyncCallback;
 import com.google.gwt.user.client.ui.Composite;
 import com.google.gwt.user.client.ui.HTML;
@@ -65,6 +68,7 @@ import com.google.gwt.user.client.ui.HorizontalPanel;
 import com.google.gwt.user.client.ui.Image;
 import com.google.gwt.user.client.ui.SimplePanel;
 import com.google.gwt.user.client.ui.VerticalPanel;
+import com.google.gwt.user.client.ui.Widget;
 /**
  * 
  * @author Massimiliano Assante, ISTI-CNR
@@ -115,6 +119,7 @@ public class NewsFeedPanel extends Composite {
 	private UserInfo myUserInfo;
 	private FilterType currentFilter;
 	private Timer feedsTimer;
+	private ShowMoreFeeds showMoreWidget;
 	//needed to know the next range start
 	private Integer fromStartingPoint;
 
@@ -231,7 +236,7 @@ public class NewsFeedPanel extends Composite {
 		newsPanel.setVerticalAlignment(HasVerticalAlignment.ALIGN_TOP);
 		loadingImage = new Image(loading);
 		newsPanel.add(loadingImage);
-		
+
 		newsService.getUserSettings(new AsyncCallback<UserSettings>() {
 			@Override
 			public void onFailure(Throwable caught) {		
@@ -276,10 +281,19 @@ public class NewsFeedPanel extends Composite {
 			}
 		};
 		feedsTimer.scheduleRepeating(delayMillis);
-		
+
-	
+		//this is for the automatic scroll of feeds
+		Window.addWindowScrollHandler(new ScrollHandler() {
+			@Override
+			public void onWindowScroll(ScrollEvent event) {
+				boolean isInView = isScrolledIntoView(showMoreWidget);
+				if (isInView) {
+					eventBus.fireEvent(new ShowMoreUpdatesEvent());
+				}
+			}
+		});
 	}
-	
+
 	/**
 	 * stop the feeds timer (when session expires)
 	 */
@@ -300,6 +314,8 @@ public class NewsFeedPanel extends Composite {
 		case MINE:
 			showOnlyMyFeeds();
 			break;
+		default:
+			break;
 		}
 	}
 	/**
@@ -505,7 +521,8 @@ public class NewsFeedPanel extends Composite {
 						if (feeds.size() >= feedsNoPerCategory*3-1 && (!isInfrastructure)) {
 							GWT.log("Show MORE " + feedsNoPerCategory);
 							showMoreUpdatesPanel.setHorizontalAlignment(HasAlignment.ALIGN_CENTER);
-							showMoreUpdatesPanel.add(new ShowMoreFeeds(eventBus));
+							showMoreWidget = new ShowMoreFeeds(eventBus);
+							showMoreUpdatesPanel.add(showMoreWidget);
 							newsPanel.add(showMoreUpdatesPanel);
 						} 	
 						isFirstTweet = false;
@@ -530,6 +547,7 @@ public class NewsFeedPanel extends Composite {
 	 */
 	protected void doShowMoreUpdates() {	
 		showMoreUpdatesPanel.remove(0);
+		loadingImage.getElement().getStyle().setMargin(10, Unit.PX);
 		showMoreUpdatesPanel.add(loadingImage);
 		int from = (fromStartingPoint == null) ? allUpdates.size()+1 : fromStartingPoint;
 
@@ -552,7 +570,8 @@ public class NewsFeedPanel extends Composite {
 					if (c >= quantity) { //there could be more feeds
 						GWT.log("there could be more feeds");
 						showMoreUpdatesPanel.clear();
-						showMoreUpdatesPanel.add(new ShowMoreFeeds(eventBus));
+						showMoreWidget = new ShowMoreFeeds(eventBus);
+						showMoreUpdatesPanel.add(showMoreWidget);
 						newsPanel.add(showMoreUpdatesPanel);
 					}
 				}
@@ -566,6 +585,20 @@ public class NewsFeedPanel extends Composite {
 			}
 		});		
 	}
+	/**
+	 * @param widget the widget to check
+	 * @returnn true if the widget is in the visible part of the page
+	 */
+	private boolean isScrolledIntoView(Widget widget) {
+		if (widget != null) {
+			int docViewTop = Window.getScrollTop();
+			int docViewBottom = docViewTop + Window.getClientHeight();
+			int elemTop = widget.getAbsoluteTop();
+			int elemBottom = elemTop + widget.getOffsetHeight();
+			return ((elemBottom <= docViewBottom) && (elemTop >= docViewTop));
+		}		
+		return false;
+	}
 
 	private boolean isFeedPresent(EnhancedFeed toCheck) {
 		for (EnhancedFeed feed : allUpdates) {

src/main/java/org/gcube/portlets/user/newsfeed/client/templates/ShowMoreFeeds.java

@@ -4,6 +4,7 @@ import org.gcube.portlets.user.newsfeed.client.event.ShowMoreUpdatesEvent;
 
 import com.google.gwt.core.client.GWT;
 import com.google.gwt.dom.client.Style.Unit;
+import com.google.gwt.dom.client.Style.Visibility;
 import com.google.gwt.event.dom.client.ClickEvent;
 import com.google.gwt.event.shared.HandlerManager;
 import com.google.gwt.uibinder.client.UiBinder;
@@ -38,6 +39,8 @@ public class ShowMoreFeeds extends Composite {
 		caption.getElement().getStyle().setBackgroundColor("transparent");
 		caption.getElement().getStyle().setFontSize(14, Unit.PX);
 		caption.setHTML("Show more feeds");
+		//done after
+		panel.getElement().getStyle().setVisibility(Visibility.HIDDEN);
 	}	
 	
 	@UiHandler("caption")