Merge "Nele: Use NlModel.addComponents for drag/drop in InteractionManager." into studio-1.4-dev

4 files changed, 200 insertions, 210 deletions

diff --git a/designer/src/com/android/tools/idea/uibuilder/structure/NlDropEvent.java b/designer/src/com/android/tools/idea/uibuilder/model/NlDropEvent.java
index d8d110ff1a6..23e948de03c 100644
--- a/designer/src/com/android/tools/idea/uibuilder/structure/NlDropEvent.java
+++ b/designer/src/com/android/tools/idea/uibuilder/model/NlDropEvent.java
@@ -13,24 +13,27 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package com.android.tools.idea.uibuilder.structure;
+package com.android.tools.idea.uibuilder.model;
 
 import com.android.annotations.NonNull;
 
 import java.awt.*;
 import java.awt.datatransfer.DataFlavor;
 import java.awt.datatransfer.Transferable;
+import java.awt.dnd.DnDConstants;
 import java.awt.dnd.DropTargetDragEvent;
 import java.awt.dnd.DropTargetDropEvent;
 
 /**
  * This class encapsulates either a {@see DropTargetDragEvent} or a {@see DropTargetDropEvent}
  * such that we can access either instance in code common for the 2 cases.
- * This class is used in {@link NlDropListener}.
+ * <p/>
+ * Also ensure that accept is called before data is retrieved from a source that has text flavor but no designer flavor.
  */
 public class NlDropEvent {
   private final DropTargetDragEvent myDragEvent;
   private final DropTargetDropEvent myDropEvent;
+  private boolean myStatusSpecified;
 
   public NlDropEvent(@NonNull DropTargetDragEvent dragEvent) {
     myDragEvent = dragEvent;
@@ -46,7 +49,8 @@ public class NlDropEvent {
   public Point getLocation() {
     if (myDragEvent != null) {
       return myDragEvent.getLocation();
-    } else {
+    }
+    else {
       return myDropEvent.getLocation();
     }
   }
@@ -54,7 +58,8 @@ public class NlDropEvent {
   public boolean isDataFlavorSupported(@NonNull DataFlavor flavor) {
     if (myDragEvent != null) {
       return myDragEvent.isDataFlavorSupported(flavor);
-    } else {
+    }
+    else {
       return myDropEvent.isDataFlavorSupported(flavor);
     }
   }
@@ -62,33 +67,54 @@ public class NlDropEvent {
   public int getDropAction() {
     if (myDragEvent != null) {
       return myDragEvent.getDropAction();
-    } else {
+    }
+    else {
       return myDropEvent.getDropAction();
     }
   }
 
   @NonNull
   public Transferable getTransferable() {
+    if (!myStatusSpecified &&
+        !isDataFlavorSupported(ItemTransferable.DESIGNER_FLAVOR) &&
+        isDataFlavorSupported(DataFlavor.stringFlavor)) {
+      accept(DnDConstants.ACTION_COPY);
+    }
     if (myDragEvent != null) {
       return myDragEvent.getTransferable();
-    } else {
+    }
+    else {
       return myDropEvent.getTransferable();
     }
   }
 
   public void accept(int dropAction) {
-    if (myDragEvent != null) {
-      myDragEvent.acceptDrag(dropAction);
-    } else {
-      myDropEvent.acceptDrop(dropAction);
+    if (!myStatusSpecified) {
+      if (myDragEvent != null) {
+        myDragEvent.acceptDrag(dropAction);
+      }
+      else {
+        myDropEvent.acceptDrop(dropAction);
+      }
+      myStatusSpecified = true;
     }
   }
 
   public void reject() {
-    if (myDragEvent != null) {
-      myDragEvent.rejectDrag();
-    } else {
-      myDropEvent.rejectDrop();
+    if (!myStatusSpecified) {
+      if (myDragEvent != null) {
+        myDragEvent.rejectDrag();
+      }
+      else {
+        myDropEvent.rejectDrop();
+      }
+      myStatusSpecified = true;
+    }
+  }
+
+  public void complete() {
+    if (myDropEvent != null) {
+      myDropEvent.dropComplete(true);
     }
   }
 }
diff --git a/designer/src/com/android/tools/idea/uibuilder/model/NlModel.java b/designer/src/com/android/tools/idea/uibuilder/model/NlModel.java
index 272444a3315..9b69d2ea620 100644
--- a/designer/src/com/android/tools/idea/uibuilder/model/NlModel.java
+++ b/designer/src/com/android/tools/idea/uibuilder/model/NlModel.java
@@ -59,9 +59,13 @@ import org.jetbrains.android.facet.AndroidFacet;
 
 import javax.swing.Timer;
 import java.awt.*;
+import java.awt.datatransfer.DataFlavor;
 import java.awt.datatransfer.Transferable;
+import java.awt.datatransfer.UnsupportedFlavorException;
+import java.awt.dnd.InvalidDnDOperationException;
 import java.awt.event.ActionEvent;
 import java.awt.event.ActionListener;
+import java.io.IOException;
 import java.util.*;
 import java.util.List;
 
@@ -71,6 +75,7 @@ import static com.android.SdkConstants.*;
  * Model for an XML file
  */
 public class NlModel implements Disposable, ResourceChangeListener, ModificationTracker {
+  private static final Logger LOG = Logger.getInstance(NlModel.class);
   @AndroidCoordinate public static final int EMPTY_COMPONENT_SIZE = 5;
   @AndroidCoordinate public static final int VISUAL_EMPTY_COMPONENT_SIZE = 14;
 
@@ -888,6 +893,33 @@ public class NlModel implements Disposable, ResourceChangeListener, Modification
   }
 
   @Nullable
+  public static DnDTransferItem getTransferItem(@NonNull Transferable transferable, boolean allowPlaceholder) {
+    DnDTransferItem item = null;
+    try {
+      if (transferable.isDataFlavorSupported(ItemTransferable.DESIGNER_FLAVOR)) {
+        item = (DnDTransferItem)transferable.getTransferData(ItemTransferable.DESIGNER_FLAVOR);
+      }
+      else if (transferable.isDataFlavorSupported(DataFlavor.stringFlavor)) {
+        String xml = (String)transferable.getTransferData(DataFlavor.stringFlavor);
+        if (!StringUtil.isEmpty(xml)) {
+          item = new DnDTransferItem(new DnDTransferComponent("", xml, 200, 100));
+        }
+      }
+    } catch (InvalidDnDOperationException ex) {
+      if (!allowPlaceholder) {
+        return null;
+      }
+      String defaultXml = "<placeholder xmlns:android=\"http://schemas.android.com/apk/res/android\"/>";
+      item = new DnDTransferItem(new DnDTransferComponent("", defaultXml, 200, 100));
+    } catch (IOException ex) {
+      LOG.warn(ex);
+    } catch (UnsupportedFlavorException ex) {
+      LOG.warn(ex);
+    }
+    return item;
+  }
+
+  @Nullable
   public List<NlComponent> createComponents(@NonNull ScreenView screenView,
                                             @NonNull DnDTransferItem item,
                                             @NonNull InsertType insertType) {
@@ -958,15 +990,15 @@ public class NlModel implements Disposable, ResourceChangeListener, Modification
   }
 
   @NonNull
-  public InsertType determineInsertType(@NonNull DragType dragType, @NonNull DnDTransferItem item, boolean asPreview) {
-    if (item.isFromPalette()) {
+  public InsertType determineInsertType(@NonNull DragType dragType, @Nullable DnDTransferItem item, boolean asPreview) {
+    if (item != null && item.isFromPalette()) {
       return asPreview ? InsertType.CREATE_PREVIEW : InsertType.CREATE;
     }
     switch (dragType) {
       case CREATE:
         return asPreview ? InsertType.CREATE_PREVIEW : InsertType.CREATE;
       case MOVE:
-        return myId == item.getModelId() ? InsertType.MOVE_INTO : InsertType.COPY;
+        return item != null && myId != item.getModelId() ? InsertType.COPY : InsertType.MOVE_INTO;
       case COPY:
         return InsertType.COPY;
       case PASTE:
diff --git a/designer/src/com/android/tools/idea/uibuilder/surface/DragDropInteraction.java b/designer/src/com/android/tools/idea/uibuilder/surface/DragDropInteraction.java
index d334e5874b1..400a8dc1520 100644
--- a/designer/src/com/android/tools/idea/uibuilder/surface/DragDropInteraction.java
+++ b/designer/src/com/android/tools/idea/uibuilder/surface/DragDropInteraction.java
@@ -80,6 +80,9 @@ public class DragDropInteraction extends Interaction {
   /** The last accessed screen view. */
   private ScreenView myScreenView;
 
+  /** The transfer item for this drag if any */
+  private DnDTransferItem myTransferItem;
+
   public DragDropInteraction(@NonNull DesignSurface designSurface, @NonNull List<NlComponent> dragged) {
     myDesignSurface = designSurface;
     myDraggedComponents = dragged;
@@ -92,6 +95,15 @@ public class DragDropInteraction extends Interaction {
     }
   }
 
+  public void setTransferItem(@NonNull DnDTransferItem item) {
+    myTransferItem = item;
+  }
+
+  @Nullable
+  public DnDTransferItem getTransferItem() {
+    return myTransferItem;
+  }
+
   @Override
   public void begin(@SwingCoordinate int x, @SwingCoordinate int y, int modifiers) {
     super.begin(x, y, modifiers);
@@ -164,7 +176,7 @@ public class DragDropInteraction extends Interaction {
       String error = myDragHandler.update(ax, ay, modifiers);
       final List<NlComponent> added = Lists.newArrayList();
       if (commit && error == null) {
-        NlModel model = myScreenView.getModel();
+        final NlModel model = myScreenView.getModel();
         XmlFile file = model.getFile();
         String label = myType.getDescription();
         WriteCommandAction action = new WriteCommandAction(project, label, file) {
@@ -178,53 +190,8 @@ public class DragDropInteraction extends Interaction {
               before = myDragReceiver.getChild(insertIndex);
             }
 
-            ViewHandlerManager viewHandlerManager = ViewHandlerManager.get(getProject());
-
-            // Move the widget and schedule a re-render
-            for (NlComponent component : myDraggedComponents) {
-              if (!myCurrentHandler.acceptsChild(myDragReceiver, component)) {
-                continue;
-              }
-              ViewHandler viewHandler = viewHandlerManager.getHandler(component);
-              if (viewHandler != null && !viewHandler.acceptsParent(myDragReceiver, component)) {
-                continue;
-              }
-
-              // Notify parent & child about the creation and allow them to customize the objects
-              InsertType insertType =  myType == DragType.COPY ? InsertType.MOVE_INTO :
-                                       (component.getParent() != myDragReceiver ? InsertType.MOVE_INTO : InsertType.MOVE_WITHIN);
-              myCurrentHandler.onChildInserted(myDragReceiver, component, insertType);
-              if (viewHandler != null) {
-                ViewEditor editor = new ViewEditorImpl(myScreenView);
-                boolean ok = viewHandler.onCreate(editor, myDragReceiver, component, insertType);
-                if (!ok) {
-                  return;
-                }
-              }
-
-              // Also update the component hierarchy directly.
-              // This will be corrected after the next rendering job too, but anticipate it
-              // here such that tests etc can immediately see the result
-              NlComponent parent = component.getParent();
-              if (parent != null) {
-                parent.removeChild(component);
-              }
-              myDragReceiver.addChild(component, before);
-              added.add(component);
-
-              // Move XML tags
-              if (myDragReceiver.getTag() != component.getTag()) {
-                XmlTag prev = component.getTag();
-                if (before != null) {
-                  component.setTag((XmlTag)myDragReceiver.getTag().addBefore(component.getTag(), before.getTag()));
-                } else {
-                  component.setTag(myDragReceiver.getTag().addSubTag(component.getTag(), false));
-                }
-                if (myType == DragType.MOVE) {
-                  prev.delete();
-                }
-              }
-            }
+            InsertType insertType = model.determineInsertType(myType, myTransferItem, false /* not for preview */);
+            model.addComponents(myDraggedComponents, myDragReceiver, before, insertType);
           }
         };
         action.execute();
diff --git a/designer/src/com/android/tools/idea/uibuilder/surface/InteractionManager.java b/designer/src/com/android/tools/idea/uibuilder/surface/InteractionManager.java
index 5316f7ac2dc..980f505b90f 100644
--- a/designer/src/com/android/tools/idea/uibuilder/surface/InteractionManager.java
+++ b/designer/src/com/android/tools/idea/uibuilder/surface/InteractionManager.java
@@ -20,34 +20,18 @@ import com.android.annotations.Nullable;
 import com.android.annotations.VisibleForTesting;
 import com.android.tools.idea.uibuilder.api.DragType;
 import com.android.tools.idea.uibuilder.api.InsertType;
-import com.android.tools.idea.uibuilder.api.ViewEditor;
-import com.android.tools.idea.uibuilder.api.ViewHandler;
-import com.android.tools.idea.uibuilder.handlers.ViewEditorImpl;
-import com.android.tools.idea.uibuilder.handlers.ViewHandlerManager;
 import com.android.tools.idea.uibuilder.model.*;
 import com.google.common.collect.Lists;
-import com.intellij.openapi.application.Result;
-import com.intellij.openapi.command.WriteCommandAction;
-import com.intellij.openapi.diagnostic.Logger;
-import com.intellij.openapi.project.Project;
-import com.intellij.openapi.util.text.StringUtil;
-import com.intellij.psi.xml.XmlAttribute;
-import com.intellij.psi.xml.XmlFile;
-import com.intellij.psi.xml.XmlTag;
 import com.intellij.util.PsiNavigateUtil;
 
 import javax.swing.*;
 import java.awt.*;
-import java.awt.datatransfer.DataFlavor;
 import java.awt.datatransfer.Transferable;
-import java.awt.datatransfer.UnsupportedFlavorException;
 import java.awt.dnd.*;
 import java.awt.event.*;
-import java.io.IOException;
 import java.util.Collections;
 import java.util.List;
 
-import static com.android.SdkConstants.XMLNS_PREFIX;
 import static com.android.tools.idea.uibuilder.model.SelectionHandle.PIXEL_MARGIN;
 import static com.android.tools.idea.uibuilder.model.SelectionHandle.PIXEL_RADIUS;
 
@@ -58,8 +42,6 @@ import static com.android.tools.idea.uibuilder.model.SelectionHandle.PIXEL_RADIU
  * interactions and in order to update the interactions along the way.
  */
 public class InteractionManager {
-  private static final Logger LOG = Logger.getInstance(InteractionManager.class);
-
   /** The canvas which owns this {@linkplain InteractionManager}. */
   @NonNull
   private final DesignSurface mySurface;
@@ -548,65 +530,72 @@ public class InteractionManager {
     // ---- Implements DropTargetListener ----
 
     @Override
-    public void dragEnter(DropTargetDragEvent event) {
+    public void dragEnter(DropTargetDragEvent dragEvent) {
       if (myCurrentInteraction == null) {
+        NlDropEvent event = new NlDropEvent(dragEvent);
         Point location = event.getLocation();
         myLastMouseX = location.x;
         myLastMouseY = location.y;
 
-        for (DataFlavor flavor : event.getCurrentDataFlavors()) {
-          if (flavor.equals(ItemTransferable.DESIGNER_FLAVOR) ||
-              flavor.getMimeType().startsWith("text/plain;") || flavor.getMimeType().equals("text/plain")) {
-            event.acceptDrag(DnDConstants.ACTION_COPY);
-            ScreenView screenView = mySurface.getScreenView(myLastMouseX, myLastMouseY);
-            if (screenView == null) {
-              continue;
-            }
-            final NlModel model = screenView.getModel();
-            try {
-              DnDTransferItem item = getTransferItem(event.getTransferable(), true /* allow placeholders */);
-              DragType dragType = event.getDropAction() == DnDConstants.ACTION_COPY ? DragType.COPY : DragType.MOVE;
-              InsertType insertType = model.determineInsertType(dragType, item, true /* preview */);
-              List<NlComponent> dragged = model.createComponents(screenView, item, insertType);
-              if (dragged == null) {
-                continue;
-              }
-              int yOffset = 0;
-              for (NlComponent component : dragged) {
-                // todo: place the components like they were originally placed?
-                component.x = Coordinates.getAndroidX(screenView, myLastMouseX) - component.w / 2;
-                component.y = Coordinates.getAndroidY(screenView, myLastMouseY) - component.h / 2 + yOffset;
-                yOffset += component.h;
-              }
-              DragDropInteraction interaction = new DragDropInteraction(mySurface, dragged);
-              interaction.setType(DragType.COPY);
-              startInteraction(myLastMouseX, myLastMouseY, interaction, 0);
-              break;
-            }
-            catch (Exception ignore) {
-              LOG.debug(ignore);
-            }
-          }
+        ScreenView screenView = mySurface.getScreenView(myLastMouseX, myLastMouseY);
+        if (screenView == null) {
+          event.reject();
+          return;
+        }
+        NlModel model = screenView.getModel();
+        DnDTransferItem item = NlModel.getTransferItem(event.getTransferable(), true /* allow placeholders */);
+        if (item == null) {
+          event.reject();
+          return;
         }
+        DragType dragType = event.getDropAction() == DnDConstants.ACTION_COPY ? DragType.COPY : DragType.MOVE;
+        InsertType insertType = model.determineInsertType(dragType, item, true /* preview */);
+        List<NlComponent> dragged = model.createComponents(screenView, item, insertType);
+        if (dragged == null) {
+          event.reject();
+          return;
+        }
+        int yOffset = 0;
+        for (NlComponent component : dragged) {
+          // todo: keep original relative position?
+          component.x = Coordinates.getAndroidX(screenView, myLastMouseX) - component.w / 2;
+          component.y = Coordinates.getAndroidY(screenView, myLastMouseY) - component.h / 2 + yOffset;
+          yOffset += component.h;
+        }
+        DragDropInteraction interaction = new DragDropInteraction(mySurface, dragged);
+        interaction.setType(dragType);
+        interaction.setTransferItem(item);
+        startInteraction(myLastMouseX, myLastMouseY, interaction, 0);
+
+        // This determines the icon presented to the user while dragging.
+        // If we are dragging a component from the palette then use the icon for a copy, otherwise show the icon
+        // that reflects the users choice i.e. controlled by the modifier key.
+        event.accept(insertType.isCreate() ? DnDConstants.ACTION_COPY : event.getDropAction());
       }
     }
 
     @Override
-    public void dragOver(DropTargetDragEvent event) {
+    public void dragOver(DropTargetDragEvent dragEvent) {
+      NlDropEvent event = new NlDropEvent(dragEvent);
       Point location = event.getLocation();
       myLastMouseX = location.x;
       myLastMouseY = location.y;
-      if (myCurrentInteraction instanceof DragDropInteraction) {
-        myCurrentInteraction.update(myLastMouseX, myLastMouseY, myLastStateMask);
-      }
-
-      for (DataFlavor flavor : event.getCurrentDataFlavors()) {
-        if (flavor.equals(ItemTransferable.DESIGNER_FLAVOR) || String.class == flavor.getRepresentationClass()) {
-          event.acceptDrag(DnDConstants.ACTION_COPY);
-          return;
-        }
+      ScreenView screenView = mySurface.getScreenView(myLastMouseX, myLastMouseY);
+      if (screenView != null && myCurrentInteraction instanceof DragDropInteraction) {
+        DragDropInteraction interaction = (DragDropInteraction)myCurrentInteraction;
+        interaction.update(myLastMouseX, myLastMouseY, myLastStateMask);
+        DragType dragType = event.getDropAction() == DnDConstants.ACTION_COPY ? DragType.COPY : DragType.MOVE;
+        interaction.setType(dragType);
+        NlModel model = screenView.getModel();
+        InsertType insertType = model.determineInsertType(dragType, interaction.getTransferItem(), true /* preview */);
+
+        // This determines the icon presented to the user while dragging.
+        // If we are dragging a component from the palette then use the icon for a copy, otherwise show the icon
+        // that reflects the users choice i.e. controlled by the modifier key.
+        event.accept(insertType.isCreate() ? DnDConstants.ACTION_COPY : event.getDropAction());
+      } else {
+        event.reject();
       }
-      event.rejectDrag();
     }
 
     @Override
@@ -616,106 +605,82 @@ public class InteractionManager {
     @Override
     public void dragExit(DropTargetEvent event) {
       if (myCurrentInteraction instanceof DragDropInteraction) {
-        finishInteraction(myLastMouseX, myLastMouseY, myLastStateMask, true);
+        finishInteraction(myLastMouseX, myLastMouseY, myLastStateMask, true /* cancel interaction */);
       }
     }
 
     @Override
-    public void drop(final DropTargetDropEvent event) {
+    public void drop(final DropTargetDropEvent dropEvent) {
+      NlDropEvent event = new NlDropEvent(dropEvent);
       Point location = event.getLocation();
       myLastMouseX = location.x;
       myLastMouseY = location.y;
+      InsertType insertType = performDrop(event.getDropAction(), event.getTransferable());
+      if (insertType != null) {
+        // This determines how the DnD source acts to a completed drop.
+        event.accept(insertType == InsertType.COPY ? event.getDropAction() : DnDConstants.ACTION_COPY);
+        event.complete();
+      } else {
+        event.reject();
+      }
+    }
 
-      final ScreenView screenView = mySurface.getScreenView(location.x, location.y);
-      if (screenView == null) {
-        event.rejectDrop();
-        return;
+    @Nullable
+    private InsertType performDrop(int dropAction, @Nullable Transferable transferable) {
+      if (!(myCurrentInteraction instanceof DragDropInteraction)) {
+        return null;
       }
+      InsertType insertType = updateDropInteraction(dropAction, transferable);
+      finishInteraction(myLastMouseX, myLastMouseY, myLastStateMask, (insertType == null));
+      return insertType;
+    }
 
-      try {
-        event.acceptDrop(DnDConstants.ACTION_MOVE);
-        final NlModel model = screenView.getModel();
-        final Project project = model.getFacet().getModule().getProject();
-        final XmlFile file = model.getFile();
-        WriteCommandAction<Void> action = new WriteCommandAction<Void>(project, "Drop", file) {
-          @Override
-          protected void run(@NonNull Result<Void> result) throws Throwable {
-            if (myCurrentInteraction instanceof DragDropInteraction) {
-              DragDropInteraction dragDrop = (DragDropInteraction)myCurrentInteraction;
-              List<NlComponent> draggedComponents = dragDrop.getDraggedComponents();
-              NlComponent component = draggedComponents.size() == 1 ? draggedComponents.get(0) : null;
-              boolean dropCancelled = true;
-              if (component != null) {
-                if (component.getTag().getName().equals("placeholder")) {
-                  // If we were unable to read the transfer data on dragEnter, fix it here:
-                  final DnDTransferItem item = getTransferItem(event.getTransferable(), false /* do not allow placeholders */);
-                  DragType dragType = event.getDropAction() == DnDConstants.ACTION_COPY ? DragType.COPY : DragType.MOVE;
-                  InsertType insertType = model.determineInsertType(dragType, item, true /* preview */);
-                  draggedComponents = model.createComponents(screenView, item, insertType);
-                  component = draggedComponents != null && draggedComponents.size() == 1 ? draggedComponents.get(0) : null;
-                }
-              }
-              if (component != null) {
-                if (component.needsDefaultId()) {
-                  component.assignId();
-                }
-                ViewHandlerManager viewHandlerManager = ViewHandlerManager.get(getProject());
-                ViewHandler viewHandler = viewHandlerManager.getHandler(component);
-                if (viewHandler != null && dragDrop.getDragReceiver() != null) {
-                  ViewEditor editor = new ViewEditorImpl(screenView);
-                  dropCancelled = !viewHandler.onCreate(editor, dragDrop.getDragReceiver(), component, InsertType.CREATE);
-                } else {
-                  dropCancelled = false;
-                }
-              }
-              finishInteraction(myLastMouseX, myLastMouseY, myLastStateMask, dropCancelled);
-              if (component != null && component.getTag().isValid() && component.getTag().getParent() instanceof XmlTag) {
-                // Remove any xmlns: attributes once the element is added into the document
-                for (XmlAttribute attribute : component.getTag().getAttributes()) {
-                  if (attribute.getName().startsWith(XMLNS_PREFIX)) {
-                    attribute.delete();
-                  }
-                }
-              }
-            }
-          }
-        };
-        action.execute();
-        event.getDropTargetContext().dropComplete(true); // or just event.dropComplete() ?
-        model.notifyModified();
+    @Nullable
+    private InsertType updateDropInteraction(int dropAction, @Nullable Transferable transferable) {
+      if (transferable == null) {
+        return null;
       }
-      catch (Exception ignore) {
-        LOG.debug(ignore);
-        event.rejectDrop();
+      DnDTransferItem item = NlModel.getTransferItem(transferable, false /* no placeholders */);
+      if (item == null) {
+        return null;
+      }
+      ScreenView screenView = mySurface.getScreenView(myLastMouseX, myLastMouseY);
+      if (screenView == null) {
+        return null;
       }
-    }
-  }
 
-  @NonNull
-  private static DnDTransferItem getTransferItem(@NonNull Transferable transferable, boolean allowPlaceholder)
-    throws IOException, UnsupportedFlavorException {
-    DnDTransferItem item = null;
-    try {
-      if (transferable.isDataFlavorSupported(ItemTransferable.DESIGNER_FLAVOR)) {
-        item = (DnDTransferItem)transferable.getTransferData(ItemTransferable.DESIGNER_FLAVOR);
+      NlModel model = screenView.getModel();
+      DragType dragType = dropAction == DnDConstants.ACTION_COPY ? DragType.COPY : DragType.MOVE;
+      InsertType insertType = model.determineInsertType(dragType, item, false /* not for preview */);
+
+      DragDropInteraction interaction = (DragDropInteraction)myCurrentInteraction;
+      assert interaction != null;
+      interaction.setType(dragType);
+      interaction.setTransferItem(item);
+
+      List<NlComponent> dragged = interaction.getDraggedComponents();
+      List<NlComponent> components;
+      if (insertType.isMove()) {
+        components = model.getSelectionModel().getSelection();
       }
-      else if (transferable.isDataFlavorSupported(DataFlavor.stringFlavor)) {
-        String xml = (String)transferable.getTransferData(DataFlavor.stringFlavor);
-        if (!StringUtil.isEmpty(xml)) {
-          item = new DnDTransferItem(new DnDTransferComponent("", xml, 200, 100));
+      else {
+        components = model.createComponents(screenView, item, insertType);
+        if (components == null) {
+          return null;  // User cancelled
         }
       }
-    } catch (InvalidDnDOperationException ex) {
-      if (!allowPlaceholder) {
-        throw ex;
+      if (dragged.size() != components.size()) {
+        throw new AssertionError(
+          String.format("Problem with drop: dragged.size(%1$d) != components.size(%1$d)", dragged.size(), components.size()));
       }
-      String defaultXml = "<placeholder xmlns:android=\"http://schemas.android.com/apk/res/android\"/>";
-      item = new DnDTransferItem(new DnDTransferComponent("", defaultXml, 200, 100));
-    }
-    if (item == null) {
-      throw new UnsupportedFlavorException(null);
+      for (int index = 0; index < dragged.size(); index++) {
+        components.get(index).x = dragged.get(index).x;
+        components.get(index).y = dragged.get(index).y;
+      }
+      dragged.clear();
+      dragged.addAll(components);
+      return insertType;
     }
-    return item;
   }
 
   @VisibleForTesting