Improvements to relative layout move and delete operations

This changeset improves the way the RelativeLayout editing support in
the layout editor handles deletions and moves.

First, during a move, if the move is simply within the same layout,
then the layout constraints are left alone such that if you for
example have

      A
      v
      B < C < D

and you move B up to be next to A, you end up with

      A < B < C < D

(It will however remove cycles if the move would result in them.)

Second, it now handles deletion better where deleting a view will
cause all references to any deleted views to be replaced by transitive
constraints.

For example, if you hve

     A < B < C < D

and you delete B and C, you end up with

     A < D

Change-Id: Icb9d3552e60aee20192f7941fe52be71ba52557f

14 files changed, 883 insertions, 89 deletions

diff --git a/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/common/layout/GridLayoutRule.java b/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/common/layout/GridLayoutRule.java
index 4f2590293..40063f2a2 100644
--- a/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/common/layout/GridLayoutRule.java
+++ b/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/common/layout/GridLayoutRule.java
@@ -403,8 +403,9 @@ public class GridLayoutRule extends BaseLayoutRule {
     }
 
     @Override
-    public void onRemovingChildren(@NonNull List<INode> deleted, @NonNull INode parent) {
-        super.onRemovingChildren(deleted, parent);
+    public void onRemovingChildren(@NonNull List<INode> deleted, @NonNull INode parent,
+            boolean moved) {
+        super.onRemovingChildren(deleted, parent, moved);
 
         // Attempt to clean up spacer objects for any newly-empty rows or columns
         // as the result of this deletion
diff --git a/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/common/layout/RelativeLayoutRule.java b/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/common/layout/RelativeLayoutRule.java
index e23f9f455..850d0177b 100644
--- a/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/common/layout/RelativeLayoutRule.java
+++ b/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/common/layout/RelativeLayoutRule.java
@@ -17,7 +17,6 @@
 package com.android.ide.common.layout;
 
 import static com.android.ide.common.layout.LayoutConstants.ATTR_GRAVITY;
-import static com.android.ide.common.layout.LayoutConstants.ATTR_ID;
 import static com.android.ide.common.layout.LayoutConstants.ATTR_LAYOUT_ABOVE;
 import static com.android.ide.common.layout.LayoutConstants.ATTR_LAYOUT_ALIGN_BASELINE;
 import static com.android.ide.common.layout.LayoutConstants.ATTR_LAYOUT_ALIGN_BOTTOM;
@@ -36,8 +35,6 @@ import static com.android.ide.common.layout.LayoutConstants.ATTR_LAYOUT_CENTER_V
 import static com.android.ide.common.layout.LayoutConstants.ATTR_LAYOUT_PREFIX;
 import static com.android.ide.common.layout.LayoutConstants.ATTR_LAYOUT_TO_LEFT_OF;
 import static com.android.ide.common.layout.LayoutConstants.ATTR_LAYOUT_TO_RIGHT_OF;
-import static com.android.ide.common.layout.LayoutConstants.ID_PREFIX;
-import static com.android.ide.common.layout.LayoutConstants.NEW_ID_PREFIX;
 import static com.android.ide.common.layout.LayoutConstants.VALUE_TRUE;
 import static com.android.utils.XmlUtils.ANDROID_URI;
 
@@ -48,7 +45,6 @@ import com.android.ide.common.api.IDragElement;
 import com.android.ide.common.api.IGraphics;
 import com.android.ide.common.api.IMenuCallback;
 import com.android.ide.common.api.INode;
-import com.android.ide.common.api.INode.IAttribute;
 import com.android.ide.common.api.INodeHandler;
 import com.android.ide.common.api.IViewRule;
 import com.android.ide.common.api.InsertType;
@@ -57,6 +53,7 @@ import com.android.ide.common.api.Rect;
 import com.android.ide.common.api.RuleAction;
 import com.android.ide.common.api.SegmentType;
 import com.android.ide.common.layout.relative.ConstraintPainter;
+import com.android.ide.common.layout.relative.DeletionHandler;
 import com.android.ide.common.layout.relative.GuidelinePainter;
 import com.android.ide.common.layout.relative.MoveHandler;
 import com.android.ide.common.layout.relative.ResizeHandler;
@@ -66,10 +63,8 @@ import java.net.URL;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
-import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
-import java.util.Set;
 
 /**
  * An {@link IViewRule} for android.widget.RelativeLayout and all its derived
@@ -161,7 +156,7 @@ public class RelativeLayoutRule extends BaseLayoutRule {
     @Override
     public DropFeedback onDropMove(@NonNull INode targetNode, @NonNull IDragElement[] elements,
             @Nullable DropFeedback feedback, @NonNull Point p) {
-        if (elements == null || elements.length == 0) {
+        if (elements == null || elements.length == 0 || feedback == null) {
             return null;
         }
 
@@ -184,6 +179,10 @@ public class RelativeLayoutRule extends BaseLayoutRule {
     @Override
     public void onDropped(final @NonNull INode targetNode, final @NonNull IDragElement[] elements,
             final @Nullable DropFeedback feedback, final @NonNull Point p) {
+        if (feedback == null) {
+            return;
+        }
+
         final MoveHandler state = (MoveHandler) feedback.userData;
 
         final Map<String, Pair<String, String>> idMap = getDropIdMap(targetNode, elements,
@@ -251,40 +250,14 @@ public class RelativeLayoutRule extends BaseLayoutRule {
     }
 
     @Override
-    public void onRemovingChildren(@NonNull List<INode> deleted, @NonNull INode parent) {
-        super.onRemovingChildren(deleted, parent);
-
-        // Remove any attachments pointing to the deleted nodes.
-
-        // Produce set of attribute values that we want to delete if
-        // present in a layout attribute
-        Set<String> removeValues = new HashSet<String>(deleted.size() * 2);
-        for (INode node : deleted) {
-            String id = node.getStringAttr(ANDROID_URI, ATTR_ID);
-            if (id != null) {
-                removeValues.add(id);
-                if (id.startsWith(NEW_ID_PREFIX)) {
-                    removeValues.add(ID_PREFIX + stripIdPrefix(id));
-                } else {
-                    removeValues.add(NEW_ID_PREFIX + stripIdPrefix(id));
-                }
-            }
-        }
-
-        for (INode child : parent.getChildren()) {
-            if (deleted.contains(child)) {
-                continue;
-            }
-            for (IAttribute attribute : child.getLiveAttributes()) {
-                if (attribute.getName().startsWith(ATTR_LAYOUT_PREFIX) &&
-                        ANDROID_URI.equals(attribute.getUri())) {
-                    String value = attribute.getValue();
-                    if (removeValues.contains(value)) {
-                        // Unset this reference to a deleted widget.
-                        child.setAttribute(ANDROID_URI, attribute.getName(), null);
-                    }
-                }
-            }
+    public void onRemovingChildren(@NonNull List<INode> deleted, @NonNull INode parent,
+            boolean moved) {
+        super.onRemovingChildren(deleted, parent, moved);
+
+        if (!moved) {
+            DeletionHandler handler = new DeletionHandler(deleted, Collections.<INode>emptyList(),
+                    parent);
+            handler.updateConstraints();
         }
     }
 
@@ -303,6 +276,10 @@ public class RelativeLayoutRule extends BaseLayoutRule {
     public void onResizeUpdate(@Nullable DropFeedback feedback, @NonNull INode child,
             @NonNull INode parent, @NonNull Rect newBounds,
             int modifierMask) {
+        if (feedback == null) {
+            return;
+        }
+
         ResizeHandler state = (ResizeHandler) feedback.userData;
         state.updateResize(feedback, child, newBounds, modifierMask);
     }
@@ -310,6 +287,9 @@ public class RelativeLayoutRule extends BaseLayoutRule {
     @Override
     public void onResizeEnd(@Nullable DropFeedback feedback, @NonNull INode child,
             @NonNull INode parent, final @NonNull Rect newBounds) {
+        if (feedback == null) {
+            return;
+        }
         final ResizeHandler state = (ResizeHandler) feedback.userData;
 
         child.editXml("Resize", new INodeHandler() {
diff --git a/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/common/layout/relative/ConstraintType.java b/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/common/layout/relative/ConstraintType.java
index 7c6fae840..bb320861c 100644
--- a/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/common/layout/relative/ConstraintType.java
+++ b/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/common/layout/relative/ConstraintType.java
@@ -40,6 +40,8 @@ import static com.android.ide.common.layout.LayoutConstants.ATTR_LAYOUT_CENTER_V
 import static com.android.ide.common.layout.LayoutConstants.ATTR_LAYOUT_TO_LEFT_OF;
 import static com.android.ide.common.layout.LayoutConstants.ATTR_LAYOUT_TO_RIGHT_OF;
 
+import com.android.annotations.NonNull;
+import com.android.annotations.Nullable;
 import com.android.ide.common.api.SegmentType;
 
 import java.util.HashMap;
@@ -138,7 +140,8 @@ enum ConstraintType {
      * @param attribute the name of the attribute to look up
      * @return the corresponding {@link ConstraintType}
      */
-    public static ConstraintType fromAttribute(String attribute) {
+    @Nullable
+    public static ConstraintType fromAttribute(@NonNull String attribute) {
         if (sNameToType == null) {
             ConstraintType[] types = ConstraintType.values();
             Map<String, ConstraintType> map = new HashMap<String, ConstraintType>(types.length);
@@ -169,6 +172,7 @@ enum ConstraintType {
      * @param to the target edge
      * @return a {@link ConstraintType}, or null
      */
+    @Nullable
     public static ConstraintType forMatch(boolean withParent, SegmentType from, SegmentType to) {
         // Attached to parent edge?
         if (withParent) {
diff --git a/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/common/layout/relative/DeletionHandler.java b/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/common/layout/relative/DeletionHandler.java
new file mode 100644
index 000000000..30f12c06a
--- /dev/null
+++ b/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/common/layout/relative/DeletionHandler.java
@@ -0,0 +1,267 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ *
+ * Licensed under the Eclipse Public License, Version 1.0 (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.eclipse.org/org/documents/epl-v10.php
+ *
+ * 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.android.ide.common.layout.relative;
+
+import static com.android.ide.common.layout.BaseViewRule.stripIdPrefix;
+import static com.android.ide.common.layout.LayoutConstants.ATTR_ID;
+import static com.android.ide.common.layout.LayoutConstants.ATTR_LAYOUT_MARGIN;
+import static com.android.ide.common.layout.LayoutConstants.ATTR_LAYOUT_PREFIX;
+import static com.android.ide.common.layout.LayoutConstants.ID_PREFIX;
+import static com.android.ide.common.layout.LayoutConstants.NEW_ID_PREFIX;
+import static com.android.ide.common.layout.relative.ConstraintType.LAYOUT_CENTER_HORIZONTAL;
+import static com.android.ide.common.layout.relative.ConstraintType.LAYOUT_CENTER_VERTICAL;
+import static com.android.utils.XmlUtils.ANDROID_URI;
+
+import com.android.annotations.NonNull;
+import com.android.annotations.Nullable;
+import com.android.ide.common.api.INode;
+import com.android.ide.common.api.INode.IAttribute;
+import com.android.ide.common.layout.LayoutConstants;
+import com.google.common.collect.Maps;
+import com.google.common.collect.Sets;
+
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+/**
+ * Handles deletions in a relative layout, transferring constraints across
+ * deleted nodes
+ * <p>
+ * TODO: Consider adding the
+ * {@link LayoutConstants#ATTR_LAYOUT_ALIGN_WITH_PARENT_MISSING} attribute to a
+ * node if it's pointing to a node which is deleted and which has no transitive
+ * reference to another node.
+ */
+public class DeletionHandler {
+    private final INode mLayout;
+    private final INode[] mChildren;
+    private final List<INode> mDeleted;
+    private final Set<String> mDeletedIds;
+    private final Map<String, INode> mNodeMap;
+    private final List<INode> mMoved;
+
+    /**
+     * Creates a new {@link DeletionHandler}
+     *
+     * @param deleted the deleted nodes
+     * @param moved nodes that were moved (e.g. deleted, but also inserted elsewhere)
+     * @param layout the parent layout of the deleted nodes
+     */
+    public DeletionHandler(@NonNull List<INode> deleted, @NonNull List<INode> moved,
+            @NonNull INode layout) {
+        mDeleted = deleted;
+        mMoved = moved;
+        mLayout = layout;
+
+        mChildren = mLayout.getChildren();
+        mNodeMap = Maps.newHashMapWithExpectedSize(mChildren.length);
+        for (INode child : mChildren) {
+            String id = child.getStringAttr(ANDROID_URI, ATTR_ID);
+            if (id != null) {
+                mNodeMap.put(stripIdPrefix(id), child);
+            }
+        }
+
+        mDeletedIds = Sets.newHashSetWithExpectedSize(mDeleted.size());
+        for (INode node : mDeleted) {
+            String id = node.getStringAttr(ANDROID_URI, ATTR_ID);
+            if (id != null) {
+                mDeletedIds.add(stripIdPrefix(id));
+            }
+        }
+
+        // Any widgets that remain (e.g. typically because they were moved) should
+        // keep their incoming dependencies
+        for (INode node : mMoved) {
+            String id = node.getStringAttr(ANDROID_URI, ATTR_ID);
+            if (id != null) {
+                mDeletedIds.remove(stripIdPrefix(id));
+            }
+        }
+    }
+
+    @Nullable
+    private static String getId(@NonNull IAttribute attribute) {
+        if (attribute.getName().startsWith(ATTR_LAYOUT_PREFIX)
+                && ANDROID_URI.equals(attribute.getUri())
+                && !attribute.getName().startsWith(ATTR_LAYOUT_MARGIN)) {
+            String id = attribute.getValue();
+            // It might not be an id reference, so check manually rather than just
+            // calling stripIdPrefix():
+            if (id.startsWith(NEW_ID_PREFIX)) {
+                return id.substring(NEW_ID_PREFIX.length());
+            } else if (id.startsWith(ID_PREFIX)) {
+                return id.substring(ID_PREFIX.length());
+            }
+        }
+
+        return null;
+    }
+
+    /**
+     * Updates the constraints in the layout to handle deletion of a set of
+     * nodes. This ensures that any constraints pointing to one of the deleted
+     * nodes are changed properly to point to a non-deleted node with similar
+     * constraints.
+     */
+    public void updateConstraints() {
+        if (mChildren.length == mDeleted.size()) {
+            // Deleting everything: Nothing to be done
+            return;
+        }
+
+        // Now remove incoming edges to any views that were deleted. If possible,
+        // don't just delete them but replace them with a transitive constraint, e.g.
+        // if we have "A <= B <= C" and "B" is removed, then we end up with "A <= C",
+
+        for (INode child : mChildren) {
+            if (mDeleted.contains(child)) {
+                continue;
+            }
+
+            for (IAttribute attribute : child.getLiveAttributes()) {
+                String id = getId(attribute);
+                if (id != null) {
+                    if (mDeletedIds.contains(id)) {
+                        // Unset this reference to a deleted widget. It might be
+                        // replaced if the pointed to node points to some other node
+                        // on the same side, but it may use a different constraint name,
+                        // or have none at all (e.g. parent).
+                        String name = attribute.getName();
+                        child.setAttribute(ANDROID_URI, name, null);
+
+                        INode deleted = mNodeMap.get(id);
+                        if (deleted != null) {
+                            ConstraintType type = ConstraintType.fromAttribute(name);
+                            if (type != null) {
+                                transfer(deleted, child, type, 0);
+                            }
+                        }
+                    }
+                }
+            }
+        }
+    }
+
+    private void transfer(INode deleted, INode target, ConstraintType targetType, int depth) {
+        if (depth == 20) {
+            // Prevent really deep flow or unbounded recursion in case there is a bug in
+            // the cycle detection code
+            return;
+        }
+
+        assert mDeleted.contains(deleted);
+
+        for (IAttribute attribute : deleted.getLiveAttributes()) {
+            String name = attribute.getName();
+            ConstraintType type = ConstraintType.fromAttribute(name);
+            if (type == null) {
+                continue;
+            }
+
+            ConstraintType transfer = getCompatibleConstraint(type, targetType);
+            if (transfer != null) {
+                String id = getId(attribute);
+                if (id != null) {
+                    if (mDeletedIds.contains(id)) {
+                        INode nextDeleted = mNodeMap.get(id);
+                        if (nextDeleted != null) {
+                            // Points to another deleted node: recurse
+                            transfer(nextDeleted, target, targetType, depth + 1);
+                        }
+                    } else {
+                        // Found an undeleted node destination: point to it directly.
+                        // Note that we're using the
+                        target.setAttribute(ANDROID_URI, transfer.name, attribute.getValue());
+                    }
+                } else {
+                    // Pointing to parent or center etc (non-id ref): replicate this on the target
+                    target.setAttribute(ANDROID_URI, name, attribute.getValue());
+                }
+            }
+        }
+    }
+
+    /**
+     * Determines if two constraints are in the same direction and if so returns
+     * the constraint in the same direction. Rather than returning boolean true
+     * or false, this returns the constraint which is sometimes modified. For
+     * example, if you have a node which points left to a node which is centered
+     * in parent, then the constraint is turned into center horizontal.
+     */
+    @Nullable
+    private static ConstraintType getCompatibleConstraint(
+            @NonNull ConstraintType first, @NonNull ConstraintType second) {
+        if (first == second) {
+            return first;
+        }
+
+        switch (second) {
+            case ALIGN_LEFT:
+            case LAYOUT_RIGHT_OF:
+                switch (first) {
+                    case LAYOUT_CENTER_HORIZONTAL:
+                    case LAYOUT_LEFT_OF:
+                    case ALIGN_LEFT:
+                        return first;
+                    case LAYOUT_CENTER_IN_PARENT:
+                        return LAYOUT_CENTER_HORIZONTAL;
+                }
+                return null;
+
+            case ALIGN_RIGHT:
+            case LAYOUT_LEFT_OF:
+                switch (first) {
+                    case LAYOUT_CENTER_HORIZONTAL:
+                    case ALIGN_RIGHT:
+                    case LAYOUT_LEFT_OF:
+                        return first;
+                    case LAYOUT_CENTER_IN_PARENT:
+                        return LAYOUT_CENTER_HORIZONTAL;
+                }
+                return null;
+
+            case ALIGN_TOP:
+            case LAYOUT_BELOW:
+            case ALIGN_BASELINE:
+                switch (first) {
+                    case LAYOUT_CENTER_VERTICAL:
+                    case ALIGN_TOP:
+                    case LAYOUT_BELOW:
+                    case ALIGN_BASELINE:
+                        return first;
+                    case LAYOUT_CENTER_IN_PARENT:
+                        return LAYOUT_CENTER_VERTICAL;
+                }
+                return null;
+            case ALIGN_BOTTOM:
+            case LAYOUT_ABOVE:
+                switch (first) {
+                    case LAYOUT_CENTER_VERTICAL:
+                    case ALIGN_BOTTOM:
+                    case LAYOUT_ABOVE:
+                    case ALIGN_BASELINE:
+                        return first;
+                    case LAYOUT_CENTER_IN_PARENT:
+                        return LAYOUT_CENTER_VERTICAL;
+                }
+                return null;
+        }
+
+        return null;
+    }
+}
diff --git a/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/common/layout/relative/GuidelineHandler.java b/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/common/layout/relative/GuidelineHandler.java
index e6b50ba0e..135cabe79 100644
--- a/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/common/layout/relative/GuidelineHandler.java
+++ b/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/common/layout/relative/GuidelineHandler.java
@@ -51,7 +51,6 @@ import static com.android.ide.common.layout.LayoutConstants.VALUE_N_DP;
 import static com.android.ide.common.layout.LayoutConstants.VALUE_TRUE;
 import static com.android.ide.common.layout.relative.ConstraintType.ALIGN_BASELINE;
 import static com.android.utils.XmlUtils.ANDROID_URI;
-
 import static java.lang.Math.abs;
 
 import com.android.ide.common.api.DropFeedback;
@@ -292,6 +291,11 @@ public class GuidelineHandler {
         return false;
     }
 
+    /**
+     * Checks for any cycles in the dependencies
+     *
+     * @param feedback the drop feedback state
+     */
     public void checkCycles(DropFeedback feedback) {
         // Deliberate short circuit evaluation -- only list the first cycle
         feedback.errorMessage = null;
@@ -658,6 +662,7 @@ public class GuidelineHandler {
         }
     }
 
+    /** Breaks any cycles detected by the handler */
     public void removeCycles() {
         if (mHorizontalCycle != null) {
             removeCycles(mHorizontalDeps);
diff --git a/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/common/layout/relative/MoveHandler.java b/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/common/layout/relative/MoveHandler.java
index 7b237a2f4..cc1953ac2 100644
--- a/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/common/layout/relative/MoveHandler.java
+++ b/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/common/layout/relative/MoveHandler.java
@@ -25,7 +25,6 @@ import static com.android.ide.common.api.SegmentType.RIGHT;
 import static com.android.ide.common.api.SegmentType.TOP;
 import static com.android.ide.common.layout.LayoutConstants.ATTR_ID;
 import static com.android.utils.XmlUtils.ANDROID_URI;
-
 import static java.lang.Math.abs;
 
 import com.android.ide.common.api.DropFeedback;
@@ -49,8 +48,15 @@ import java.util.List;
  * edges, and so on -- and picks the best among these.
  */
 public class MoveHandler extends GuidelineHandler {
-    public int mDraggedBaseline;
-
+    private int mDraggedBaseline;
+
+    /**
+     * Creates a new {@link MoveHandler}.
+     *
+     * @param layout the layout element the handler is operating on
+     * @param elements the elements being dragged in the move operation
+     * @param rulesEngine the corresponding {@link IClientRulesEngine}
+     */
     public MoveHandler(INode layout, IDragElement[] elements, IClientRulesEngine rulesEngine) {
         super(layout, rulesEngine);
 
@@ -159,6 +165,15 @@ public class MoveHandler extends GuidelineHandler {
         }
     }
 
+    /**
+     * Updates the handler for the given mouse move
+     *
+     * @param feedback the feedback handler
+     * @param elements the elements being dragged
+     * @param offsetX the new mouse X coordinate
+     * @param offsetY the new mouse Y coordinate
+     * @param modifierMask the keyboard modifiers pressed during the drag
+     */
     public void updateMove(DropFeedback feedback, IDragElement[] elements,
             int offsetX, int offsetY, int modifierMask) {
         mSnap = (modifierMask & DropFeedback.MODIFIER2) == 0;
diff --git a/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/common/layout/relative/ResizeHandler.java b/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/common/layout/relative/ResizeHandler.java
index d1d8f37b6..0e4472420 100644
--- a/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/common/layout/relative/ResizeHandler.java
+++ b/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/common/layout/relative/ResizeHandler.java
@@ -25,7 +25,6 @@ import static com.android.ide.common.api.SegmentType.RIGHT;
 import static com.android.ide.common.api.SegmentType.TOP;
 import static com.android.ide.common.layout.LayoutConstants.ATTR_ID;
 import static com.android.utils.XmlUtils.ANDROID_URI;
-
 import static java.lang.Math.abs;
 
 import com.android.ide.common.api.DropFeedback;
@@ -44,10 +43,18 @@ import java.util.Set;
  * edges in a RelativeLayout.
  */
 public class ResizeHandler extends GuidelineHandler {
-    public final INode mResized;
-    public final SegmentType mHorizontalEdgeType;
-    public final SegmentType mVerticalEdgeType;
-
+    private final SegmentType mHorizontalEdgeType;
+    private final SegmentType mVerticalEdgeType;
+
+    /**
+     * Creates a new {@link ResizeHandler}
+     *
+     * @param layout the layout containing the resized node
+     * @param resized the node being resized
+     * @param rulesEngine the applicable {@link IClientRulesEngine}
+     * @param horizontalEdgeType the type of horizontal edge being resized, or null
+     * @param verticalEdgeType the type of vertical edge being resized, or null
+     */
     public ResizeHandler(INode layout, INode resized,
             IClientRulesEngine rulesEngine,
             SegmentType horizontalEdgeType, SegmentType verticalEdgeType) {
@@ -58,7 +65,6 @@ public class ResizeHandler extends GuidelineHandler {
         assert horizontalEdgeType != CENTER_HORIZONTAL && verticalEdgeType != CENTER_HORIZONTAL;
         assert horizontalEdgeType != CENTER_VERTICAL && verticalEdgeType != CENTER_VERTICAL;
 
-        mResized = resized;
         mHorizontalEdgeType = horizontalEdgeType;
         mVerticalEdgeType = verticalEdgeType;
 
@@ -162,6 +168,14 @@ public class ResizeHandler extends GuidelineHandler {
         return compatible;
     }
 
+    /**
+     * Updates the handler for the given mouse resize
+     *
+     * @param feedback the feedback handler
+     * @param child the node being resized
+     * @param newBounds the new bounds of the resize rectangle
+     * @param modifierMask the keyboard modifiers pressed during the drag
+     */
     public void updateResize(DropFeedback feedback, INode child, Rect newBounds,
             int modifierMask) {
         mSnap = (modifierMask & DropFeedback.MODIFIER2) == 0;
diff --git a/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/editors/layout/gle2/ClipboardSupport.java b/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/editors/layout/gle2/ClipboardSupport.java
index 21e005f59..dbb414460 100644
--- a/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/editors/layout/gle2/ClipboardSupport.java
+++ b/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/editors/layout/gle2/ClipboardSupport.java
@@ -142,9 +142,7 @@ public class ClipboardSupport {
      */
     public void cutSelectionToClipboard(List<SelectionItem> selection) {
         copySelectionToClipboard(selection);
-        deleteSelection(
-                mCanvas.getCutLabel(),
-                selection);
+        deleteSelection(mCanvas.getCutLabel(), selection);
     }
 
     /**
@@ -170,9 +168,11 @@ public class ClipboardSupport {
         for (SelectionItem cs : selection) {
             CanvasViewInfo vi = cs.getViewInfo();
             if (vi != null && vi.getParent() != null) {
+                CanvasViewInfo parent = vi.getParent();
+                assert parent != null;
                 if (title == null) {
-                    title = vi.getParent().getName();
-                } else if (!title.equals(vi.getParent().getName())) {
+                    title = parent.getName();
+                } else if (!title.equals(parent.getName())) {
                     // More than one kind of parent selected.
                     title = null;
                     break;
@@ -210,6 +210,9 @@ public class ClipboardSupport {
                         new HashMap<NodeProxy, List<INode>>();
                 for (SelectionItem cs : selection) {
                     NodeProxy node = cs.getNode();
+                    if (node == null) {
+                        continue;
+                    }
                     INode parent = node.getParent();
                     if (parent != null) {
                         List<INode> children = clusters.get(parent);
diff --git a/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/editors/layout/gle2/MoveGesture.java b/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/editors/layout/gle2/MoveGesture.java
index c2a535e2b..520396db8 100644
--- a/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/editors/layout/gle2/MoveGesture.java
+++ b/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/editors/layout/gle2/MoveGesture.java
@@ -404,6 +404,7 @@ public class MoveGesture extends DropGesture {
                     if (event.detail == DND.DROP_MOVE) {
                         GlobalCanvasDragInfo.getInstance().removeSource();
                     }
+                    mTargetNode.applyPendingChanges();
                 }
             });
         } finally {
diff --git a/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/editors/layout/gre/RulesEngine.java b/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/editors/layout/gre/RulesEngine.java
index a8438d8ea..7dc908b08 100755
--- a/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/editors/layout/gre/RulesEngine.java
+++ b/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/editors/layout/gre/RulesEngine.java
@@ -558,7 +558,8 @@ public class RulesEngine {
             IViewRule parentRule = loadRule(parentUiNode);
             if (parentRule != null) {
                 try {
-                    parentRule.onRemovingChildren(children, parentNode);
+                    parentRule.onRemovingChildren(children, parentNode,
+                            mInsertType == InsertType.MOVE_WITHIN);
                 } catch (Exception e) {
                     AdtPlugin.log(e, "%s.onDispose() failed: %s",
                             parentRule.getClass().getSimpleName(),
diff --git a/eclipse/plugins/com.android.ide.eclipse.tests/unittests/com/android/ide/common/layout/TestNode.java b/eclipse/plugins/com.android.ide.eclipse.tests/unittests/com/android/ide/common/layout/TestNode.java
index b9176f6c0..372e329c2 100644
--- a/eclipse/plugins/com.android.ide.eclipse.tests/unittests/com/android/ide/common/layout/TestNode.java
+++ b/eclipse/plugins/com.android.ide.eclipse.tests/unittests/com/android/ide/common/layout/TestNode.java
@@ -36,8 +36,10 @@ import com.android.ide.eclipse.adt.internal.editors.formatting.XmlPrettyPrinter;
 import com.android.ide.eclipse.adt.internal.editors.layout.gle2.DomUtilities;
 import com.google.common.base.Splitter;
 
+import org.w3c.dom.Attr;
 import org.w3c.dom.Document;
 import org.w3c.dom.Element;
+import org.w3c.dom.NamedNodeMap;
 
 import java.io.IOException;
 import java.io.StringWriter;
@@ -336,8 +338,24 @@ public class TestNode implements INode {
         }
 
         @Override
+        public @NonNull IAttribute[] getLiveAttributes() {
+            List<IAttribute> result = new ArrayList<IAttribute>();
+
+            NamedNodeMap attributes = mElement.getAttributes();
+            for (int i = 0, n = attributes.getLength(); i < n; i++) {
+                Attr attribute = (Attr) attributes.item(i);
+                result.add(new TestXmlAttribute(attribute));
+            }
+            return result.toArray(new IAttribute[result.size()]);
+        }
+
+        @Override
         public boolean setAttribute(String uri, String localName, String value) {
-            mElement.setAttributeNS(uri, localName, value);
+            if (value == null) {
+                mElement.removeAttributeNS(uri, localName);
+            } else {
+                mElement.setAttributeNS(uri, localName, value);
+            }
             return super.setAttribute(uri, localName, value);
         }
 
@@ -395,6 +413,33 @@ public class TestNode implements INode {
         }
     }
 
+    public static class TestXmlAttribute implements IAttribute {
+        private Attr mAttribute;
+
+        public TestXmlAttribute(Attr attribute) {
+            this.mAttribute = attribute;
+        }
+
+        @Override
+        public String getUri() {
+            return mAttribute.getNamespaceURI();
+        }
+
+        @Override
+        public String getName() {
+            String name = mAttribute.getLocalName();
+            if (name == null) {
+                name = mAttribute.getName();
+            }
+            return name;
+        }
+
+        @Override
+        public String getValue() {
+            return mAttribute.getValue();
+        }
+    }
+
     // Recursively initialize this node with the bounds specified in the given hierarchy
     // dump (from ViewHierarchy's DUMP_INFO flag
     public void assignBounds(String bounds) {
diff --git a/eclipse/plugins/com.android.ide.eclipse.tests/unittests/com/android/ide/common/layout/relative/DeletionHandlerTest.java b/eclipse/plugins/com.android.ide.eclipse.tests/unittests/com/android/ide/common/layout/relative/DeletionHandlerTest.java
new file mode 100644
index 000000000..f5ec1ba24
--- /dev/null
+++ b/eclipse/plugins/com.android.ide.eclipse.tests/unittests/com/android/ide/common/layout/relative/DeletionHandlerTest.java
@@ -0,0 +1,445 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ *
+ * Licensed under the Eclipse Public License, Version 1.0 (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.eclipse.org/org/documents/epl-v10.php
+ *
+ * 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.android.ide.common.layout.relative;
+
+import static com.android.ide.common.layout.LayoutConstants.ATTR_ID;
+import static com.android.tools.lint.detector.api.LintConstants.ANDROID_URI;
+
+import com.android.ide.common.api.INode;
+import com.android.ide.common.layout.BaseViewRule;
+import com.android.ide.common.layout.TestNode;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+
+import junit.framework.TestCase;
+
+@SuppressWarnings("javadoc")
+public class DeletionHandlerTest extends TestCase {
+    public void testSimple() {
+        String xml = "" +
+            "<?xml version=\"1.0\" encoding=\"utf-8\"?>\n" +
+            "<RelativeLayout xmlns:android=\"http://schemas.android.com/apk/res/android\"\n" +
+            "    xmlns:tools=\"http://schemas.android.com/tools\"\n" +
+            "    android:layout_width=\"match_parent\"\n" +
+            "    android:layout_height=\"match_parent\"\n" +
+            "    tools:ignore=\"HardcodedText\" >\n" +
+            "\n" +
+            "    <Button\n" +
+            "        android:id=\"@+id/button1\"\n" +
+            "        android:layout_width=\"wrap_content\"\n" +
+            "        android:layout_height=\"wrap_content\"\n" +
+            "        android:layout_alignParentLeft=\"true\"\n" +
+            "        android:text=\"A\" />\n" +
+            "\n" +
+            "    <Button\n" +
+            "        android:id=\"@+id/button2\"\n" +
+            "        android:layout_width=\"wrap_content\"\n" +
+            "        android:layout_height=\"wrap_content\"\n" +
+            "        android:layout_alignBaseline=\"@+id/button1\"\n" +
+            "        android:layout_alignBottom=\"@+id/button1\"\n" +
+            "        android:layout_toRightOf=\"@+id/button1\"\n" +
+            "        android:text=\"B\" />\n" +
+            "\n" +
+            "    <Button\n" +
+            "        android:id=\"@+id/button3\"\n" +
+            "        android:layout_width=\"wrap_content\"\n" +
+            "        android:layout_height=\"wrap_content\"\n" +
+            "        android:layout_alignBottom=\"@+id/button2\"\n" +
+            "        android:layout_toRightOf=\"@+id/button2\"\n" +
+            "        android:text=\"C\" />\n" +
+            "\n" +
+            "</RelativeLayout>";
+        TestNode targetNode = TestNode.createFromXml(xml);
+        assertNotNull(targetNode);
+
+        TestNode button2 = TestNode.findById(targetNode, "@+id/button2");
+
+        INode layout = button2.getParent();
+        List<INode> deletedNodes = Collections.<INode>singletonList(button2);
+        List<INode> movedNodes = Collections.<INode>emptyList();
+        assertSame(layout, targetNode);
+        layout.removeChild(button2);
+
+        DeletionHandler handler = new DeletionHandler(deletedNodes, movedNodes, layout);
+        handler.updateConstraints();
+
+        String updated = TestNode.toXml(targetNode);
+        assertEquals(
+                "<?xml version=\"1.0\" encoding=\"utf-8\"?>\n" +
+                "<RelativeLayout xmlns:android=\"http://schemas.android.com/apk/res/android\"\n" +
+                "    xmlns:tools=\"http://schemas.android.com/tools\"\n" +
+                "    android:layout_width=\"match_parent\"\n" +
+                "    android:layout_height=\"match_parent\"\n" +
+                "    tools:ignore=\"HardcodedText\">\n" +
+                "\n" +
+                "    <Button\n" +
+                "        android:id=\"@+id/button1\"\n" +
+                "        android:layout_width=\"wrap_content\"\n" +
+                "        android:layout_height=\"wrap_content\"\n" +
+                "        android:layout_alignParentLeft=\"true\"\n" +
+                "        android:text=\"A\">\n" +
+                "    </Button>\n" +
+                "\n" +
+                "    <Button\n" +
+                "        android:id=\"@+id/button3\"\n" +
+                "        android:layout_width=\"wrap_content\"\n" +
+                "        android:layout_height=\"wrap_content\"\n" +
+                "        android:layout_alignBaseline=\"@+id/button1\"\n" +
+                "        android:layout_alignBottom=\"@+id/button1\"\n" +
+                "        android:layout_toRightOf=\"@+id/button1\"\n" +
+                "        android:text=\"C\">\n" +
+                "    </Button>\n" +
+                "\n" +
+                "</RelativeLayout>",
+                updated);
+        assertFalse(updated.contains(BaseViewRule.stripIdPrefix(button2.getStringAttr(ANDROID_URI,
+                ATTR_ID))));
+    }
+
+    public void testTransitive() {
+        String xml = "" +
+            "<?xml version=\"1.0\" encoding=\"utf-8\"?>\n" +
+            "<RelativeLayout xmlns:android=\"http://schemas.android.com/apk/res/android\"\n" +
+            "    xmlns:tools=\"http://schemas.android.com/tools\"\n" +
+            "    android:layout_width=\"match_parent\"\n" +
+            "    android:layout_height=\"match_parent\"\n" +
+            "    tools:ignore=\"HardcodedText\" >\n" +
+            "\n" +
+            "    <Button\n" +
+            "        android:id=\"@+id/button1\"\n" +
+            "        android:layout_width=\"wrap_content\"\n" +
+            "        android:layout_height=\"wrap_content\"\n" +
+            "        android:layout_alignParentLeft=\"true\"\n" +
+            "        android:layout_alignParentTop=\"true\"\n" +
+            "        android:text=\"Above\" />\n" +
+            "\n" +
+            "    <Button\n" +
+            "        android:id=\"@+id/button2\"\n" +
+            "        android:layout_width=\"wrap_content\"\n" +
+            "        android:layout_height=\"wrap_content\"\n" +
+            "        android:layout_alignParentLeft=\"true\"\n" +
+            "        android:layout_below=\"@+id/button1\"\n" +
+            "        android:text=\"A\" />\n" +
+            "\n" +
+            "    <Button\n" +
+            "        android:id=\"@+id/button3\"\n" +
+            "        android:layout_width=\"wrap_content\"\n" +
+            "        android:layout_height=\"wrap_content\"\n" +
+            "        android:layout_alignBaseline=\"@+id/button2\"\n" +
+            "        android:layout_alignBottom=\"@+id/button2\"\n" +
+            "        android:layout_toRightOf=\"@+id/button2\"\n" +
+            "        android:text=\"B\" />\n" +
+            "\n" +
+            "    <Button\n" +
+            "        android:id=\"@+id/button4\"\n" +
+            "        android:layout_width=\"wrap_content\"\n" +
+            "        android:layout_height=\"wrap_content\"\n" +
+            "        android:layout_alignBottom=\"@+id/button3\"\n" +
+            "        android:layout_toRightOf=\"@+id/button3\"\n" +
+            "        android:text=\"C\" />\n" +
+            "\n" +
+            "    <Button\n" +
+            "        android:id=\"@+id/button5\"\n" +
+            "        android:layout_width=\"wrap_content\"\n" +
+            "        android:layout_height=\"wrap_content\"\n" +
+            "        android:layout_alignBaseline=\"@+id/button4\"\n" +
+            "        android:layout_alignBottom=\"@+id/button4\"\n" +
+            "        android:layout_toRightOf=\"@+id/button4\"\n" +
+            "        android:text=\"D\" />\n" +
+            "\n" +
+            "    <Button\n" +
+            "        android:id=\"@+id/button6\"\n" +
+            "        android:layout_width=\"wrap_content\"\n" +
+            "        android:layout_height=\"wrap_content\"\n" +
+            "        android:layout_alignBottom=\"@+id/button5\"\n" +
+            "        android:layout_toRightOf=\"@+id/button5\"\n" +
+            "        android:text=\"E\" />\n" +
+            "\n" +
+            "    <Button\n" +
+            "        android:id=\"@+id/button7\"\n" +
+            "        android:layout_width=\"wrap_content\"\n" +
+            "        android:layout_height=\"wrap_content\"\n" +
+            "        android:layout_alignLeft=\"@+id/button3\"\n" +
+            "        android:layout_below=\"@+id/button3\"\n" +
+            "        android:text=\"Button\" />\n" +
+            "\n" +
+            "    <CheckBox\n" +
+            "        android:id=\"@+id/checkBox1\"\n" +
+            "        android:layout_width=\"wrap_content\"\n" +
+            "        android:layout_height=\"wrap_content\"\n" +
+            "        android:layout_alignBaseline=\"@+id/button7\"\n" +
+            "        android:layout_alignBottom=\"@+id/button7\"\n" +
+            "        android:layout_toRightOf=\"@+id/button7\"\n" +
+            "        android:text=\"CheckBox\" />\n" +
+            "\n" +
+            "    <Button\n" +
+            "        android:id=\"@+id/button8\"\n" +
+            "        android:layout_width=\"wrap_content\"\n" +
+            "        android:layout_height=\"wrap_content\"\n" +
+            "        android:layout_below=\"@+id/checkBox1\"\n" +
+            "        android:layout_toRightOf=\"@+id/checkBox1\"\n" +
+            "        android:text=\"Button\" />\n" +
+            "\n" +
+            "</RelativeLayout>";
+        TestNode targetNode = TestNode.createFromXml(xml);
+        assertNotNull(targetNode);
+        TestNode button7 = TestNode.findById(targetNode, "@+id/button7");
+        TestNode checkBox = TestNode.findById(targetNode, "@+id/checkBox1");
+
+        INode layout = button7.getParent();
+        List<INode> deletedNodes = Arrays.<INode>asList(button7, checkBox);
+        List<INode> movedNodes = Collections.<INode>emptyList();
+        assertSame(layout, targetNode);
+        layout.removeChild(button7);
+        layout.removeChild(checkBox);
+
+        DeletionHandler handler = new DeletionHandler(deletedNodes, movedNodes, layout);
+        handler.updateConstraints();
+
+        String updated = TestNode.toXml(targetNode);
+        assertEquals(
+                "<?xml version=\"1.0\" encoding=\"utf-8\"?>\n" +
+                "<RelativeLayout xmlns:android=\"http://schemas.android.com/apk/res/android\"\n" +
+                "    xmlns:tools=\"http://schemas.android.com/tools\"\n" +
+                "    android:layout_width=\"match_parent\"\n" +
+                "    android:layout_height=\"match_parent\"\n" +
+                "    tools:ignore=\"HardcodedText\">\n" +
+                "\n" +
+                "    <Button\n" +
+                "        android:id=\"@+id/button1\"\n" +
+                "        android:layout_width=\"wrap_content\"\n" +
+                "        android:layout_height=\"wrap_content\"\n" +
+                "        android:layout_alignParentLeft=\"true\"\n" +
+                "        android:layout_alignParentTop=\"true\"\n" +
+                "        android:text=\"Above\">\n" +
+                "    </Button>\n" +
+                "\n" +
+                "    <Button\n" +
+                "        android:id=\"@+id/button2\"\n" +
+                "        android:layout_width=\"wrap_content\"\n" +
+                "        android:layout_height=\"wrap_content\"\n" +
+                "        android:layout_alignParentLeft=\"true\"\n" +
+                "        android:layout_below=\"@+id/button1\"\n" +
+                "        android:text=\"A\">\n" +
+                "    </Button>\n" +
+                "\n" +
+                "    <Button\n" +
+                "        android:id=\"@+id/button3\"\n" +
+                "        android:layout_width=\"wrap_content\"\n" +
+                "        android:layout_height=\"wrap_content\"\n" +
+                "        android:layout_alignBaseline=\"@+id/button2\"\n" +
+                "        android:layout_alignBottom=\"@+id/button2\"\n" +
+                "        android:layout_toRightOf=\"@+id/button2\"\n" +
+                "        android:text=\"B\">\n" +
+                "    </Button>\n" +
+                "\n" +
+                "    <Button\n" +
+                "        android:id=\"@+id/button4\"\n" +
+                "        android:layout_width=\"wrap_content\"\n" +
+                "        android:layout_height=\"wrap_content\"\n" +
+                "        android:layout_alignBottom=\"@+id/button3\"\n" +
+                "        android:layout_toRightOf=\"@+id/button3\"\n" +
+                "        android:text=\"C\">\n" +
+                "    </Button>\n" +
+                "\n" +
+                "    <Button\n" +
+                "        android:id=\"@+id/button5\"\n" +
+                "        android:layout_width=\"wrap_content\"\n" +
+                "        android:layout_height=\"wrap_content\"\n" +
+                "        android:layout_alignBaseline=\"@+id/button4\"\n" +
+                "        android:layout_alignBottom=\"@+id/button4\"\n" +
+                "        android:layout_toRightOf=\"@+id/button4\"\n" +
+                "        android:text=\"D\">\n" +
+                "    </Button>\n" +
+                "\n" +
+                "    <Button\n" +
+                "        android:id=\"@+id/button6\"\n" +
+                "        android:layout_width=\"wrap_content\"\n" +
+                "        android:layout_height=\"wrap_content\"\n" +
+                "        android:layout_alignBottom=\"@+id/button5\"\n" +
+                "        android:layout_toRightOf=\"@+id/button5\"\n" +
+                "        android:text=\"E\">\n" +
+                "    </Button>\n" +
+                "\n" +
+                "    <Button\n" +
+                "        android:id=\"@+id/button8\"\n" +
+                "        android:layout_width=\"wrap_content\"\n" +
+                "        android:layout_height=\"wrap_content\"\n" +
+                "        android:layout_alignLeft=\"@+id/button3\"\n" +
+                "        android:layout_below=\"@+id/button3\"\n" +
+                "        android:text=\"Button\">\n" +
+                "    </Button>\n" +
+                "\n" +
+                "</RelativeLayout>",
+                updated);
+        assertFalse(updated.contains(BaseViewRule.stripIdPrefix(button7.getStringAttr(ANDROID_URI,
+                ATTR_ID))));
+    }
+
+    public void testCenter() {
+        String xml =
+            "<?xml version=\"1.0\" encoding=\"utf-8\"?>\n" +
+            "<RelativeLayout xmlns:android=\"http://schemas.android.com/apk/res/android\"\n" +
+            "    xmlns:tools=\"http://schemas.android.com/tools\"\n" +
+            "    android:layout_width=\"match_parent\"\n" +
+            "    android:layout_height=\"match_parent\"\n" +
+            "    tools:ignore=\"HardcodedText\" >\n" +
+            "\n" +
+            "    <Button\n" +
+            "        android:id=\"@+id/button1\"\n" +
+            "        android:layout_width=\"wrap_content\"\n" +
+            "        android:layout_height=\"wrap_content\"\n" +
+            "        android:layout_centerInParent=\"true\"\n" +
+            "        android:text=\"Button\" />\n" +
+            "\n" +
+            "    <CheckBox\n" +
+            "        android:id=\"@+id/checkBox1\"\n" +
+            "        android:layout_width=\"wrap_content\"\n" +
+            "        android:layout_height=\"wrap_content\"\n" +
+            "        android:layout_below=\"@+id/button1\"\n" +
+            "        android:layout_toRightOf=\"@+id/button1\"\n" +
+            "        android:text=\"CheckBox\" />\n" +
+            "\n" +
+            "</RelativeLayout>";
+
+        TestNode targetNode = TestNode.createFromXml(xml);
+        assertNotNull(targetNode);
+        TestNode button1 = TestNode.findById(targetNode, "@+id/button1");
+
+        INode layout = button1.getParent();
+        List<INode> deletedNodes = Collections.<INode>singletonList(button1);
+        List<INode> movedNodes = Collections.<INode>emptyList();
+        assertSame(layout, targetNode);
+        layout.removeChild(button1);
+
+        DeletionHandler handler = new DeletionHandler(deletedNodes, movedNodes, layout);
+        handler.updateConstraints();
+
+        String updated = TestNode.toXml(targetNode);
+        assertEquals(
+                "<?xml version=\"1.0\" encoding=\"utf-8\"?>\n" +
+                "<RelativeLayout xmlns:android=\"http://schemas.android.com/apk/res/android\"\n" +
+                "    xmlns:tools=\"http://schemas.android.com/tools\"\n" +
+                "    android:layout_width=\"match_parent\"\n" +
+                "    android:layout_height=\"match_parent\"\n" +
+                "    tools:ignore=\"HardcodedText\">\n" +
+                "\n" +
+                "    <CheckBox\n" +
+                "        android:id=\"@+id/checkBox1\"\n" +
+                "        android:layout_width=\"wrap_content\"\n" +
+                "        android:layout_height=\"wrap_content\"\n" +
+                "        android:layout_centerInParent=\"true\"\n" +
+                "        android:text=\"CheckBox\">\n" +
+                "    </CheckBox>\n" +
+                "\n" +
+                "</RelativeLayout>",
+                updated);
+        assertFalse(updated.contains(BaseViewRule.stripIdPrefix(button1.getStringAttr(ANDROID_URI,
+                ATTR_ID))));
+
+    }
+
+    public void testMove() {
+        String xml = "" +
+            "<?xml version=\"1.0\" encoding=\"utf-8\"?>\n" +
+            "<RelativeLayout xmlns:android=\"http://schemas.android.com/apk/res/android\"\n" +
+            "    xmlns:tools=\"http://schemas.android.com/tools\"\n" +
+            "    android:layout_width=\"match_parent\"\n" +
+            "    android:layout_height=\"match_parent\"\n" +
+            "    tools:ignore=\"HardcodedText\" >\n" +
+            "\n" +
+            "    <Button\n" +
+            "        android:id=\"@+id/button1\"\n" +
+            "        android:layout_width=\"wrap_content\"\n" +
+            "        android:layout_height=\"wrap_content\"\n" +
+            "        android:layout_alignParentLeft=\"true\"\n" +
+            "        android:text=\"A\" />\n" +
+            "\n" +
+            "    <Button\n" +
+            "        android:id=\"@+id/button2\"\n" +
+            "        android:layout_width=\"wrap_content\"\n" +
+            "        android:layout_height=\"wrap_content\"\n" +
+            "        android:layout_alignBaseline=\"@+id/button1\"\n" +
+            "        android:layout_alignBottom=\"@+id/button1\"\n" +
+            "        android:layout_toRightOf=\"@+id/button1\"\n" +
+            "        android:text=\"B\" />\n" +
+            "\n" +
+            "    <Button\n" +
+            "        android:id=\"@+id/button3\"\n" +
+            "        android:layout_width=\"wrap_content\"\n" +
+            "        android:layout_height=\"wrap_content\"\n" +
+            "        android:layout_alignBottom=\"@+id/button2\"\n" +
+            "        android:layout_toRightOf=\"@+id/button2\"\n" +
+            "        android:text=\"C\" />\n" +
+            "\n" +
+            "</RelativeLayout>";
+        TestNode targetNode = TestNode.createFromXml(xml);
+        assertNotNull(targetNode);
+
+        TestNode button2 = TestNode.findById(targetNode, "@+id/button2");
+
+        INode layout = button2.getParent();
+        List<INode> deletedNodes = Collections.<INode>singletonList(button2);
+        List<INode> movedNodes = Collections.<INode>singletonList(button2);
+        assertSame(layout, targetNode);
+
+        DeletionHandler handler = new DeletionHandler(deletedNodes, movedNodes, layout);
+        handler.updateConstraints();
+
+        String updated = TestNode.toXml(targetNode);
+        assertEquals(
+                "<?xml version=\"1.0\" encoding=\"utf-8\"?>\n" +
+                "<RelativeLayout xmlns:android=\"http://schemas.android.com/apk/res/android\"\n" +
+                "    xmlns:tools=\"http://schemas.android.com/tools\"\n" +
+                "    android:layout_width=\"match_parent\"\n" +
+                "    android:layout_height=\"match_parent\"\n" +
+                "    tools:ignore=\"HardcodedText\">\n" +
+                "\n" +
+                "    <Button\n" +
+                "        android:id=\"@+id/button1\"\n" +
+                "        android:layout_width=\"wrap_content\"\n" +
+                "        android:layout_height=\"wrap_content\"\n" +
+                "        android:layout_alignParentLeft=\"true\"\n" +
+                "        android:text=\"A\">\n" +
+                "    </Button>\n" +
+                "\n" +
+                "    <Button\n" +
+                "        android:id=\"@+id/button2\"\n" +
+                "        android:layout_width=\"wrap_content\"\n" +
+                "        android:layout_height=\"wrap_content\"\n" +
+                "        android:layout_alignBaseline=\"@+id/button1\"\n" +
+                "        android:layout_alignBottom=\"@+id/button1\"\n" +
+                "        android:layout_toRightOf=\"@+id/button1\"\n" +
+                "        android:text=\"B\">\n" +
+                "    </Button>\n" +
+                "\n" +
+                "    <Button\n" +
+                "        android:id=\"@+id/button3\"\n" +
+                "        android:layout_width=\"wrap_content\"\n" +
+                "        android:layout_height=\"wrap_content\"\n" +
+                "        android:layout_alignBottom=\"@+id/button2\"\n" +
+                "        android:layout_toRightOf=\"@+id/button2\"\n" +
+                "        android:text=\"C\">\n" +
+                "    </Button>\n" +
+                "\n" +
+                "</RelativeLayout>",
+                updated);
+        assertTrue(updated.contains(BaseViewRule.stripIdPrefix(button2.getStringAttr(ANDROID_URI,
+                ATTR_ID))));
+    }
+}
diff --git a/rule_api/src/com/android/ide/common/api/AbstractViewRule.java b/rule_api/src/com/android/ide/common/api/AbstractViewRule.java
index 7f058095b..068580fc8 100644
--- a/rule_api/src/com/android/ide/common/api/AbstractViewRule.java
+++ b/rule_api/src/com/android/ide/common/api/AbstractViewRule.java
@@ -47,8 +47,6 @@ public class AbstractViewRule implements IViewRule {
         return null;
     }
 
-    // ==== Selection ====
-
     @Override
     @Nullable
     public List<String> getSelectionHint(@NonNull INode parentNode, @NonNull INode childNode) {
@@ -69,12 +67,10 @@ public class AbstractViewRule implements IViewRule {
             @NonNull List<? extends INode> childNodes, @Nullable Object view) {
     }
 
-    // ==== Drag & drop support ====
-
-    // By default Views do not accept drag'n'drop.
     @Override
     @Nullable
-    public DropFeedback onDropEnter(@NonNull INode targetNode, @Nullable Object targetView, @Nullable IDragElement[] elements) {
+    public DropFeedback onDropEnter(@NonNull INode targetNode, @Nullable Object targetView,
+            @Nullable IDragElement[] elements) {
         return null;
     }
 
@@ -86,7 +82,8 @@ public class AbstractViewRule implements IViewRule {
     }
 
     @Override
-    public void onDropLeave(@NonNull INode targetNode, @NonNull IDragElement[] elements, @Nullable DropFeedback feedback) {
+    public void onDropLeave(@NonNull INode targetNode, @NonNull IDragElement[] elements,
+            @Nullable DropFeedback feedback) {
         // ignore
     }
 
@@ -101,39 +98,42 @@ public class AbstractViewRule implements IViewRule {
 
 
     @Override
-    public void onPaste(@NonNull INode targetNode, @Nullable Object targetView, @NonNull IDragElement[] pastedElements) {
+    public void onPaste(@NonNull INode targetNode, @Nullable Object targetView,
+            @NonNull IDragElement[] pastedElements) {
     }
 
-    // ==== Create/Remove hooks ====
-
     @Override
-    public void onCreate(@NonNull INode node, @NonNull INode parent, @NonNull InsertType insertType) {
+    public void onCreate(@NonNull INode node, @NonNull INode parent,
+            @NonNull InsertType insertType) {
     }
 
     @Override
-    public void onChildInserted(@NonNull INode child, @NonNull INode parent, @NonNull InsertType insertType) {
+    public void onChildInserted(@NonNull INode child, @NonNull INode parent,
+            @NonNull InsertType insertType) {
     }
 
     @Override
-    public void onRemovingChildren(@NonNull List<INode> deleted, @NonNull INode parent) {
+    public void onRemovingChildren(@NonNull List<INode> deleted, @NonNull INode parent,
+            boolean moved) {
     }
 
-    // ==== Resizing ====
-
     @Override
     @Nullable
-    public DropFeedback onResizeBegin(@NonNull INode child, @NonNull INode parent, @Nullable SegmentType horizontalEdge,
-            @Nullable SegmentType verticalEdge, @Nullable Object childView, @Nullable Object parentView) {
+    public DropFeedback onResizeBegin(@NonNull INode child, @NonNull INode parent,
+            @Nullable SegmentType horizontalEdge,
+            @Nullable SegmentType verticalEdge, @Nullable Object childView,
+            @Nullable Object parentView) {
         return null;
     }
 
     @Override
-    public void onResizeUpdate(@Nullable DropFeedback feedback, @NonNull INode child, @NonNull INode parent, @NonNull Rect newBounds,
+    public void onResizeUpdate(@Nullable DropFeedback feedback, @NonNull INode child,
+            @NonNull INode parent, @NonNull Rect newBounds,
             int modifierMask) {
     }
 
     @Override
-    public void onResizeEnd(@Nullable DropFeedback feedback, @NonNull INode child, final @NonNull INode parent,
-            final @NonNull Rect newBounds) {
+    public void onResizeEnd(@Nullable DropFeedback feedback, @NonNull INode child,
+            @NonNull INode parent, @NonNull Rect newBounds) {
     }
 }
diff --git a/rule_api/src/com/android/ide/common/api/IViewRule.java b/rule_api/src/com/android/ide/common/api/IViewRule.java
index c11579507..b16df266c 100644
--- a/rule_api/src/com/android/ide/common/api/IViewRule.java
+++ b/rule_api/src/com/android/ide/common/api/IViewRule.java
@@ -298,19 +298,32 @@ public interface IViewRule {
             @NonNull InsertType insertType);
 
     /**
-     * Called when one or more children are about to be deleted by the user. Note that
-     * children deleted programmatically from view rules (via
+     * Called when one or more children are about to be deleted by the user.
+     * Note that children deleted programmatically from view rules (via
      * {@link INode#removeChild(INode)}) will not notify about deletion.
      * <p>
-     * Note that this method will be called under an edit lock, so rules can directly
-     * add/remove nodes and attributes as part of the deletion handling (and their
-     * actions will be part of the same undo-unit.)
+     * Note that this method will be called under an edit lock, so rules can
+     * directly add/remove nodes and attributes as part of the deletion handling
+     * (and their actions will be part of the same undo-unit.)
+     * <p>
+     * Note that when children are moved (such as when you drag a child within a
+     * LinearLayout to move it from one position among the children to another),
+     * that will also result in a
+     * {@link #onChildInserted(INode, INode, InsertType)} (with the
+     * {@code InsertType} set to {@link InsertType#MOVE_WITHIN}) and a remove
+     * via this {@link #onRemovingChildren(List, INode, boolean)} method. When
+     * the deletion is occurring as part of a local move (insert + delete), the
+     * {@code moved} parameter to this method is set to true.
      *
      * @param deleted a nonempty list of children about to be deleted
-     * @param parent the parent of the deleted children (which still contains the children
-     *            since this method is called before the deletion is performed)
+     * @param parent the parent of the deleted children (which still contains
+     *            the children since this method is called before the deletion
+     *            is performed)
+     * @param moved when true, the nodes are being deleted as part of a local
+     *            move (where copies are inserted elsewhere)
      */
-    void onRemovingChildren(@NonNull List<INode> deleted, @NonNull INode parent);
+    void onRemovingChildren(@NonNull List<INode> deleted, @NonNull INode parent,
+            boolean moved);
 
     /**
      * Called by the IDE on the parent layout when a child widget is being resized. This