WIP: Automatically scroll drop target Grid

client/src/main/java/com/vaadin/client/connectors/grid/GridDropTargetConnector.java

@@ -29,6 +29,9 @@ import com.vaadin.client.WidgetUtil;
 import com.vaadin.client.extensions.DropTargetExtensionConnector;
 import com.vaadin.client.widget.escalator.RowContainer;
 import com.vaadin.client.widget.escalator.RowContainer.BodyRowContainer;
+import com.vaadin.client.widget.grid.AutoScroller;
+import com.vaadin.client.widget.grid.AutoScroller.AutoScrollerCallback;
+import com.vaadin.client.widget.grid.AutoScroller.ScrollAxis;
 import com.vaadin.client.widgets.Escalator;
 import com.vaadin.shared.MouseEventDetails;
 import com.vaadin.shared.Range;
@@ -92,6 +95,11 @@ public class GridDropTargetConnector extends DropTargetExtensionConnector {
      */
     private Element latestTargetElement;
 
+    private AutoScroller autoScroller;
+    private int pageY;
+
+    private double timeStamp;
+
     @Override
     protected void extend(ServerConnector target) {
         gridConnector = (GridConnector) target;
@@ -145,6 +153,7 @@ public class GridDropTargetConnector extends DropTargetExtensionConnector {
      *            drop target element
      * @param event
      *            drop event
+     * @return the drop location
      */
     protected DropLocation getDropLocation(Element target, NativeEvent event) {
         if (TableRowElement.is(target)) {
@@ -190,6 +199,19 @@ public class GridDropTargetConnector extends DropTargetExtensionConnector {
         super.onDragEnter(event);
     }
 
+    @Override
+    protected void onDragOver(Event event) {
+        super.onDragOver(event);
+
+        int pageY = WidgetUtil.getTouchOrMouseClientY((NativeEvent) event);
+        double timeStamp = event.getTimeStamp();
+        if (this.pageY != pageY && ((timeStamp - this.timeStamp > 150))) {
+            autoScroller.updatePointerCoordinates(0, pageY);
+            this.pageY = pageY;
+            this.timeStamp = timeStamp;
+        }
+    }
+
     @Override
     protected void addDragOverStyle(NativeEvent event) {
         Element targetElement = getTargetElement(
@@ -215,6 +237,13 @@ public class GridDropTargetConnector extends DropTargetExtensionConnector {
             targetElement.addClassName(className);
             currentStyleName = className;
         }
+
+        // initialize auto scroller
+        if (autoScroller == null) {
+            autoScroller = new AutoScroller(gridConnector.getWidget());
+            autoScroller.start(event, ScrollAxis.VERTICAL,
+                    new NooplAutoScrollerCallback(), false);
+        }
     }
 
     private String getTargetClassName(Element target, NativeEvent event) {
@@ -245,6 +274,11 @@ public class GridDropTargetConnector extends DropTargetExtensionConnector {
         Element targetElement = getTargetElement(
                 (Element) event.getEventTarget().cast());
         removeStyles(targetElement);
+
+        if (autoScroller != null) {
+            autoScroller.stop();
+            autoScroller = null;
+        }
     }
 
     private void removeStyles(Element element) {
@@ -332,4 +366,21 @@ public class GridDropTargetConnector extends DropTargetExtensionConnector {
     public GridDropTargetState getState() {
         return (GridDropTargetState) super.getState();
     }
+
+    private final class NooplAutoScrollerCallback
+            implements AutoScrollerCallback {
+
+        @Override
+        public void onAutoScroll(int scrollDiff) {
+        }
+
+        @Override
+        public void onAutoScrollReachedMin() {
+        }
+
+        @Override
+        public void onAutoScrollReachedMax() {
+        }
+
+    }
 }

client/src/main/java/com/vaadin/client/widget/grid/AutoScroller.java

@@ -15,6 +15,9 @@
  */
 package com.vaadin.client.widget.grid;
 
+import java.util.Date;
+import java.util.logging.Logger;
+
 import com.google.gwt.animation.client.AnimationScheduler;
 import com.google.gwt.animation.client.AnimationScheduler.AnimationCallback;
 import com.google.gwt.animation.client.AnimationScheduler.AnimationHandle;
@@ -123,7 +126,9 @@ public class AutoScroller {
             }
 
             case Event.ONTOUCHMOVE:
-                event.cancel();
+                if (cancelEvent) {
+                    event.cancel();
+                }
                 break;
 
             case Event.ONTOUCHEND:
@@ -331,6 +336,8 @@ public class AutoScroller {
 
         public void updatePointerCoords(int pageX, int pageY) {
             final int pageCordinate;
+            Logger.getLogger("UPDATE").warning("X:" + pageX + " Y:" + pageY
+                    + " time:" + new Date().getTime());
             if (scrollDirection == ScrollAxis.VERTICAL) {
                 pageCordinate = pageY;
             } else {
@@ -447,6 +454,8 @@ public class AutoScroller {
 
     private AutoScrollerCallback callback;
 
+    private boolean cancelEvent;
+
     /**
      * Creates a new instance for scrolling the given grid.
      *
@@ -469,12 +478,32 @@ public class AutoScroller {
      */
     public void start(final NativeEvent startEvent, ScrollAxis scrollAxis,
             AutoScrollerCallback callback) {
+        start(startEvent, scrollAxis, callback, true);
+    }
+
+    /**
+     * Starts the automatic scrolling detection.
+     *
+     * @param startEvent
+     *            the event that starts the automatic scroll
+     * @param scrollAxis
+     *            the axis along which the scrolling should happen
+     * @param callback
+     *            the callback for getting info about the automatic scrolling
+     * @param cancelEvent
+     *            should auto scroller cancel the native events or not
+     */
+    public void start(final NativeEvent startEvent, ScrollAxis scrollAxis,
+            AutoScrollerCallback callback, boolean cancelEvent) {
         scrollDirection = scrollAxis;
         this.callback = callback;
+        this.cancelEvent = cancelEvent;
         injectNativeHandler();
         start();
-        startEvent.preventDefault();
-        startEvent.stopPropagation();
+        if (cancelEvent) {
+            startEvent.preventDefault();
+            startEvent.stopPropagation();
+        }
     }
 
     /**
@@ -645,4 +674,21 @@ public class AutoScroller {
         return grid.getScrollHeight() - getTfootElement().getOffsetHeight()
                 - getTheadElement().getOffsetHeight();
     }
+
+    /**
+     * Update the current page coordinates.
+     * <p>
+     * This method exists if there is no onmousemove or ontouchmove events
+     * happening, but the automatic scrolling should still be happening. This
+     * can be the case when e.g. HTML5 DnD is used (no onmousemove fired).
+     *
+     * @param pageX
+     *            the page X coordinate
+     * @param pageY
+     *            the page Y coordinate
+     * @since 8.1
+     */
+    public void updatePointerCoordinates(int pageX, int pageY) {
+        autoScroller.updatePointerCoords(pageX, pageY);
+    }
 }