Update DragShadow states to UX spec.

There was an attempt to use LevelListDrawable for the different levels
of background of DocumentHolder, but that resulted in a weird state. Can
revisit that on another attempt.

Bug: 31182423
Change-Id: I74af77557790b1d30e316fa167ffed577eaf9032

20 files changed, 264 insertions, 89 deletions

diff --git a/res/drawable/drag_shadow_background.xml b/res/drawable/drag_shadow_background.xml
index d6ec373d5..5940bb375 100644
--- a/res/drawable/drag_shadow_background.xml
+++ b/res/drawable/drag_shadow_background.xml
@@ -21,8 +21,8 @@
       android:width="1dp"
       android:color="#ff9f9f9f" />
   <corners
-      android:bottomRightRadius="3dp"
-      android:bottomLeftRadius="3dp"
-      android:topLeftRadius="3dp"
-      android:topRightRadius="3dp"/>
+      android:bottomRightRadius="2dp"
+      android:bottomLeftRadius="2dp"
+      android:topLeftRadius="2dp"
+      android:topRightRadius="2dp"/>
 </shape>
diff --git a/res/color/item_doc_list_background_activated.xml b/res/drawable/drop_badge_states.xml
index 7d7a11086..f859b7ca1 100644
--- a/res/color/item_doc_list_background_activated.xml
+++ b/res/drawable/drop_badge_states.xml
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
-<!-- Copyright (C) 2015 The Android Open Source Project
+<!-- Copyright (C) 2016 The Android Open Source Project
 
      Licensed under the Apache License, Version 2.0 (the "License");
      you may not use this file except in compliance with the License.
@@ -14,11 +14,17 @@
      limitations under the License.
 -->
 
-<selector xmlns:android="http://schemas.android.com/apk/res/android">
+<selector xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto">
     <item
-        android:state_activated="true"
-        android:color="?android:attr/colorAccent"
-        android:alpha="0.1" />
+        app:state_droppable="true"
+        app:state_drop_hovered="true"
+        android:drawable="@drawable/ic_drop_ok_badge" />
     <item
-        android:color="@android:color/transparent" />
-</selector>
+        app:state_droppable="false"
+        app:state_drop_hovered="true"
+        android:drawable="@drawable/ic_drop_not_ok_badge" />
+    <item
+        app:state_drop_hovered="false"
+        android:drawable="@android:color/transparent" />
+</selector>
\ No newline at end of file
diff --git a/res/drawable/ic_drop_not_ok_badge.xml b/res/drawable/ic_drop_not_ok_badge.xml
new file mode 100644
index 000000000..45c8b6dd7
--- /dev/null
+++ b/res/drawable/ic_drop_not_ok_badge.xml
@@ -0,0 +1,38 @@
+<!--
+Copyright (C) 2016 The Android Open Source Project
+
+   Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
+
+    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.
+-->
+
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+        android:width="15dp"
+        android:height="15dp"
+        android:viewportWidth="30.0"
+        android:viewportHeight="30.0">
+
+    <group
+         android:name="whiteBg">
+        <path
+            android:fillColor="#FFFFFFFF"
+            android:pathData="M0,15a15,15 0 1,0 30,0a15,15 0 1,0 -30,0" />
+    </group>
+
+    <group
+         android:name="badge"
+         android:translateX="2"
+         android:translateY="2">
+        <path
+            android:fillColor="#FFC53929"
+            android:pathData="M3.8056487,3.8056487 C-1.26854957,8.87984696 -1.26854957,17.1162267 3.8056487,22.190425 C8.87984696,27.2646233 17.1162267,27.2646233 22.190425,22.190425 C27.2646233,17.1162267 27.2646233,8.87984696 22.190425,3.8056487 C17.1162267,-1.26854957 8.87984696,-1.26854957 3.8056487,3.8056487 L3.8056487,3.8056487 Z M16.5335708,17.9477843 L12.9980369,14.4122504 L9.46250295,17.9477843 L8.04828938,16.5335708 L11.5838233,12.9980369 L8.04828938,9.46250295 L9.46250295,8.04828938 L12.9980369,11.5838233 L16.5335708,8.04828938 L17.9477843,9.46250295 L14.4122504,12.9980369 L17.9477843,16.5335708 L16.5335708,17.9477843 L16.5335708,17.9477843 Z" />
+    </group>
+</vector>
diff --git a/res/drawable/ic_drop_ok_badge.xml b/res/drawable/ic_drop_ok_badge.xml
new file mode 100644
index 000000000..48e3e838a
--- /dev/null
+++ b/res/drawable/ic_drop_ok_badge.xml
@@ -0,0 +1,37 @@
+<!--
+Copyright (C) 2016 The Android Open Source Project
+
+   Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
+
+    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.
+-->
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+        android:width="15dp"
+        android:height="15dp"
+        android:viewportWidth="30.0"
+        android:viewportHeight="30.0">
+
+    <group
+         android:name="whiteBg">
+    <path
+        android:fillColor="#FFFFFFFF"
+        android:pathData="M0,15a15,15 0 1,0 30,0a15,15 0 1,0 -30,0" />
+    </group>
+
+    <group
+         android:name="badge"
+         android:translateX="2"
+         android:translateY="2">
+    <path
+        android:fillColor="#FF0B8043"
+        android:pathData="M13,0 C5.824,0 0,5.824 0,13 C0,20.176 5.824,26 13,26 C20.176,26 26,20.176 26,13 C26,5.824 20.176,0 13,0 L13,0 Z M19,14 L14,14 L14,19 L12,19 L12,14 L7,14 L7,12 L12,12 L12,7 L14,7 L14,12 L19,12 L19,14 Z" />
+    </group>
+</vector>
diff --git a/res/drawable/item_doc_list_background.xml b/res/drawable/item_doc_list_background.xml
deleted file mode 100644
index 13910bbe3..000000000
--- a/res/drawable/item_doc_list_background.xml
+++ /dev/null
@@ -1,20 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<!-- Copyright (C) 2013 The Android Open Source Project
-
-     Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
-
-     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.
--->
-
-<shape xmlns:android="http://schemas.android.com/apk/res/android"
-       android:shape="rectangle">
-    <solid android:color="@color/item_doc_list_background_activated" />
-</shape>
diff --git a/res/layout/drag_shadow_layout.xml b/res/layout/drag_shadow_layout.xml
index 26613efdd..e94c443ae 100644
--- a/res/layout/drag_shadow_layout.xml
+++ b/res/layout/drag_shadow_layout.xml
@@ -23,13 +23,7 @@
     android:gravity="center_vertical|left"
     android:background="@drawable/drag_shadow_background">
 
-    <ImageView
-        android:id="@android:id/icon"
-        android:layout_width="@dimen/root_icon_size"
-        android:layout_height="@dimen/root_icon_size"
-        android:scaleType="centerInside"
-        android:contentDescription="@null"
-        android:duplicateParentState="true"/>
+   <include layout="@layout/drop_badge"/>
 
     <TextView
         android:id="@android:id/title"
diff --git a/res/drawable/drag_shadow_background_no_drop.xml b/res/layout/drop_badge.xml
index b92c30a66..485f400f2 100644
--- a/res/drawable/drag_shadow_background_no_drop.xml
+++ b/res/layout/drop_badge.xml
@@ -14,15 +14,11 @@
      limitations under the License.
 -->
 
-<shape xmlns:android="http://schemas.android.com/apk/res/android"
-       android:shape="rectangle">
-  <solid android:color="@color/item_drag_shadow_background_no_drop" />
-  <stroke
-      android:width="1dp"
-      android:color="#ff9f9f9f" />
-  <corners
-      android:bottomRightRadius="3dp"
-      android:bottomLeftRadius="3dp"
-      android:topLeftRadius="3dp"
-      android:topRightRadius="3dp"/>
-</shape>
+<com.android.documentsui.DropBadgeView
+        xmlns:android="http://schemas.android.com/apk/res/android"
+        android:id="@android:id/icon"
+        android:layout_width="@dimen/root_icon_size"
+        android:layout_height="@dimen/root_icon_size"
+        android:scaleType="centerInside"
+        android:contentDescription="@null"
+        android:duplicateParentState="true"/>
\ No newline at end of file
diff --git a/res/values/attrs.xml b/res/values/attrs.xml
index 46ca582e7..a5b128026 100644
--- a/res/values/attrs.xml
+++ b/res/values/attrs.xml
@@ -17,4 +17,8 @@
     <declare-styleable name="HighlightedItemView">
         <attr name="state_highlighted" format="boolean"/>
     </declare-styleable>
+    <declare-styleable name="DroppableItemView">
+        <attr name="state_droppable" format="boolean"/>
+        <attr name="state_drop_hovered" format="boolean"/>
+    </declare-styleable>
 </resources>
diff --git a/res/values/colors.xml b/res/values/colors.xml
index cb4b04cdf..09ba86d00 100644
--- a/res/values/colors.xml
+++ b/res/values/colors.xml
@@ -38,8 +38,9 @@
     <color name="item_doc_background_disabled">#fff4f4f4</color>
     <color name="item_doc_background_selected">@*android:color/accent_device_default_50</color>
     <color name="item_breadcrumb_background_hovered">#1affffff</color>
+    <color name="item_doc_droppable_background">#ffe8f0fb</color>
+    <color name="item_doc_not_droppable_background">#ffe0e0e0</color>
 
-    <color name="item_drag_shadow_background">#fffafafa</color>
-    <color name="item_drag_shadow_background_no_drop">#ffffb6c1</color>
+    <color name="item_drag_shadow_background">@*android:color/white</color>
 
 </resources>
diff --git a/res/values/dimens.xml b/res/values/dimens.xml
index ecd598eed..2c4ff9977 100644
--- a/res/values/dimens.xml
+++ b/res/values/dimens.xml
@@ -51,4 +51,7 @@
 
     <dimen name="dropdown_sort_widget_margin">20dp</dimen>
     <dimen name="dropdown_sort_widget_icon_size">30dp</dimen>
+
+    <dimen name="drop_icon_height">15dp</dimen>
+    <dimen name="drop_icon_width">15dp</dimen>
 </resources>
diff --git a/src/com/android/documentsui/DragShadowBuilder.java b/src/com/android/documentsui/DragShadowBuilder.java
index d6877ec00..24e037da9 100644
--- a/src/com/android/documentsui/DragShadowBuilder.java
+++ b/src/com/android/documentsui/DragShadowBuilder.java
@@ -23,7 +23,6 @@ import android.graphics.Rect;
 import android.graphics.drawable.Drawable;
 import android.view.LayoutInflater;
 import android.view.View;
-import android.widget.ImageView;
 import android.widget.TextView;
 
 import com.android.documentsui.base.DocumentInfo;
@@ -39,11 +38,9 @@ public final class DragShadowBuilder extends View.DragShadowBuilder {
 
     private final View mShadowView;
     private final TextView mTitle;
-    private final ImageView mIcon;
+    private final DropBadgeView mIcon;
     private final int mWidth;
     private final int mHeight;
-    private final Drawable mDefaultBackground;
-    private final Drawable mNoDropBackground;
 
     public DragShadowBuilder(Context context) {
         mWidth = context.getResources().getDimensionPixelSize(R.dimen.drag_shadow_width);
@@ -51,12 +48,11 @@ public final class DragShadowBuilder extends View.DragShadowBuilder {
 
         mShadowView = LayoutInflater.from(context).inflate(R.layout.drag_shadow_layout, null);
         mTitle = (TextView) mShadowView.findViewById(android.R.id.title);
-        mIcon = (ImageView) mShadowView.findViewById(android.R.id.icon);
+        mIcon = (DropBadgeView) mShadowView.findViewById(android.R.id.icon);
 
-        mDefaultBackground = context.getResources().getDrawable(R.drawable.drag_shadow_background,
-                null);
-        mNoDropBackground = context.getResources()
-                .getDrawable(R.drawable.drag_shadow_background_no_drop, null);
+        mShadowView
+                .setBackground(context.getResources().getDrawable(R.drawable.drag_shadow_background,
+                        null));
     }
 
     @Override
@@ -82,15 +78,17 @@ public final class DragShadowBuilder extends View.DragShadowBuilder {
     }
 
     public void updateIcon(Drawable icon) {
-        mIcon.setImageDrawable(icon);
+        mIcon.updateIcon(icon);
     }
 
     public void resetBackground() {
-        mShadowView.setBackground(mDefaultBackground);
+        mIcon.setDropHovered(false);
+        mIcon.setEnabled(false);
     }
 
-    public void setNoDropBackground() {
-        mShadowView.setBackground(mNoDropBackground);
+    public void setAppearDroppable(boolean droppable) {
+        mIcon.setDropHovered(true);
+        mIcon.setDroppable(droppable);
     }
 
     /**
diff --git a/src/com/android/documentsui/DrawerController.java b/src/com/android/documentsui/DrawerController.java
index f8062a76b..12f00ee9d 100644
--- a/src/com/android/documentsui/DrawerController.java
+++ b/src/com/android/documentsui/DrawerController.java
@@ -156,7 +156,7 @@ public abstract class DrawerController implements DrawerListener {
         }
 
         @Override
-        public void setDropTargetHighlight(View v, boolean highlight) {
+        public void setDropTargetHighlight(View v, Object localState, boolean highlight) {
         }
 
         @Override
diff --git a/src/com/android/documentsui/DropBadgeView.java b/src/com/android/documentsui/DropBadgeView.java
new file mode 100644
index 000000000..8ed67013d
--- /dev/null
+++ b/src/com/android/documentsui/DropBadgeView.java
@@ -0,0 +1,86 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
+ *
+ * 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.documentsui;
+
+import android.content.Context;
+import android.graphics.drawable.Drawable;
+import android.graphics.drawable.LayerDrawable;
+import android.util.AttributeSet;
+import android.view.Gravity;
+import android.widget.ImageView;
+
+/**
+ * Provides a way to encapsulate droppable badge toggling logic into a single class.
+ */
+public final class DropBadgeView extends ImageView {
+    private static final int[] STATE_DROPPABLE = {R.attr.state_droppable};
+    private static final int[] STATE_DROP_HOVERED = {R.attr.state_drop_hovered};
+
+    private boolean mDroppable = false;
+    private boolean mDropHovered = false;
+    private LayerDrawable mBackground;
+
+    public DropBadgeView(Context context, AttributeSet attrs) {
+        super(context, attrs);
+
+        final int badgeHeight = context.getResources()
+                .getDimensionPixelSize(R.dimen.drop_icon_height);
+        final int badgeWidth = context.getResources()
+                .getDimensionPixelSize(R.dimen.drop_icon_width);
+
+        Drawable okBadge = context.getResources().getDrawable(R.drawable.drop_badge_states, null);
+        Drawable defaultIcon = context.getResources()
+                .getDrawable(com.android.internal.R.drawable.ic_doc_generic, null);
+
+        Drawable[] list = {defaultIcon, okBadge};
+        mBackground = new LayerDrawable(list);
+
+        mBackground.setLayerGravity(1, Gravity.BOTTOM | Gravity.RIGHT);
+        mBackground.setLayerSize(1, badgeWidth, badgeHeight);
+
+        setBackground(mBackground);
+    }
+
+    @Override
+    public int[] onCreateDrawableState(int extraSpace) {
+        final int[] drawableState = super.onCreateDrawableState(extraSpace + 2);
+
+        if (mDroppable) {
+            mergeDrawableStates(drawableState, STATE_DROPPABLE);
+        }
+
+        if (mDropHovered) {
+            mergeDrawableStates(drawableState, STATE_DROP_HOVERED);
+        }
+
+        return drawableState;
+    }
+
+    public void setDroppable(boolean droppable) {
+        mDroppable = droppable;
+        refreshDrawableState();
+    }
+
+    public void setDropHovered(boolean hovered) {
+        mDropHovered = hovered;
+        refreshDrawableState();
+    }
+
+    public void updateIcon(Drawable icon) {
+        mBackground.setDrawable(0, icon);
+    }
+}
\ No newline at end of file
diff --git a/src/com/android/documentsui/HorizontalBreadcrumb.java b/src/com/android/documentsui/HorizontalBreadcrumb.java
index 240a0d3fc..598deccce 100644
--- a/src/com/android/documentsui/HorizontalBreadcrumb.java
+++ b/src/com/android/documentsui/HorizontalBreadcrumb.java
@@ -118,7 +118,7 @@ public final class HorizontalBreadcrumb extends RecyclerView
     }
 
     @Override
-    public void setDropTargetHighlight(View v, boolean highlight) {
+    public void setDropTargetHighlight(View v, Object localState, boolean highlight) {
         RecyclerView.ViewHolder vh = getChildViewHolder(v);
         if (vh instanceof BreadcrumbHolder) {
             ((BreadcrumbHolder) vh).setHighlighted(highlight);
diff --git a/src/com/android/documentsui/ItemDragListener.java b/src/com/android/documentsui/ItemDragListener.java
index 79f71d964..87c12748c 100644
--- a/src/com/android/documentsui/ItemDragListener.java
+++ b/src/com/android/documentsui/ItemDragListener.java
@@ -68,7 +68,7 @@ public class ItemDragListener<H extends DragHost> implements OnDragListener {
                 return true;
             case DragEvent.ACTION_DRAG_EXITED:
             case DragEvent.ACTION_DRAG_ENDED:
-                handleExitedEndedEvent(v);
+                handleExitedEndedEvent(v, event);
                 return true;
             case DragEvent.ACTION_DROP:
                 return handleDropEvent(v, event);
@@ -80,10 +80,10 @@ public class ItemDragListener<H extends DragHost> implements OnDragListener {
     private void handleEnteredEvent(View v, DragEvent event) {
         mDragHost.onDragEntered(v, event.getLocalState());
         @Nullable TimerTask task = createOpenTask(v, event);
+        mDragHost.setDropTargetHighlight(v, event.getLocalState(), true);
         if (task == null) {
             return;
         }
-        mDragHost.setDropTargetHighlight(v, true);
         v.setTag(R.id.drag_hovering_tag, task);
         mHoverTimer.schedule(task, SPRING_TIMEOUT);
     }
@@ -95,8 +95,8 @@ public class ItemDragListener<H extends DragHost> implements OnDragListener {
         }
     }
 
-    private void handleExitedEndedEvent(View v) {
-        mDragHost.setDropTargetHighlight(v, false);
+    private void handleExitedEndedEvent(View v, DragEvent event) {
+        mDragHost.setDropTargetHighlight(v, event.getLocalState(), false);
 
         TimerTask task = (TimerTask) v.getTag(R.id.drag_hovering_tag);
         if (task != null) {
@@ -154,9 +154,10 @@ public class ItemDragListener<H extends DragHost> implements OnDragListener {
         /**
          * Highlights/unhighlights the view to visually indicate this view is being hovered.
          * @param v the view being hovered
+         * @param localState the Local state object  given by DragEvent
          * @param highlight true if highlight the view; false if unhighlight it
          */
-        void setDropTargetHighlight(View v, boolean highlight);
+        void setDropTargetHighlight(View v, Object localState, boolean highlight);
 
         /**
          * Notifies hovering timeout has elapsed
diff --git a/src/com/android/documentsui/dirlist/DirectoryFragment.java b/src/com/android/documentsui/dirlist/DirectoryFragment.java
index 12430eb23..1f0419e8c 100644
--- a/src/com/android/documentsui/dirlist/DirectoryFragment.java
+++ b/src/com/android/documentsui/dirlist/DirectoryFragment.java
@@ -896,6 +896,12 @@ public class DirectoryFragment extends Fragment
         // For now, just always reset drag shadow when drag exits
         mActivity.getShadowBuilder().resetBackground();
         v.updateDragShadow(mActivity.getShadowBuilder());
+        if (v.getParent() == mRecView) {
+            DocumentHolder holder = getDocumentHolder(v);
+            if (holder != null) {
+                holder.resetDropHighlight();
+            }
+        }
     }
 
     void dragStopped(boolean result) {
@@ -913,16 +919,13 @@ public class DirectoryFragment extends Fragment
      * {@inheritDoc}
      *
      * In DirectoryFragment, we close the roots drawer right away.
+     * We also want to update the Drag Shadow to indicate whether the
+     * item is droppable or not.
      */
     @Override
     public void onDragEntered(View v, Object localState) {
-    mActivity.setRootsDrawerOpen(false);
-
-        if (canCopyTo(localState, v)) {
-            mActivity.getShadowBuilder().resetBackground();
-        } else {
-            mActivity.getShadowBuilder().setNoDropBackground();
-        }
+        mActivity.setRootsDrawerOpen(false);
+        mActivity.getShadowBuilder().setAppearDroppable(canCopyTo(localState, v));
         v.updateDragShadow(mActivity.getShadowBuilder());
     }
 
@@ -1004,13 +1007,17 @@ public class DirectoryFragment extends Fragment
     }
 
     @Override
-    public void setDropTargetHighlight(View v, boolean highlight) {
+    public void setDropTargetHighlight(View v, Object localState, boolean highlight) {
         // Note: use exact comparison - this code is searching for views which are children of
         // the RecyclerView instance in the UI.
         if (v.getParent() == mRecView) {
-            RecyclerView.ViewHolder vh = mRecView.getChildViewHolder(v);
-            if (vh instanceof DocumentHolder) {
-                ((DocumentHolder) vh).setDroppableHighlight(highlight);
+            DocumentHolder holder = getDocumentHolder(v);
+            if (holder != null) {
+                if (!highlight) {
+                    holder.resetDropHighlight();
+                } else {
+                    holder.setDroppableHighlight(canCopyTo(localState, v));
+                }
             }
         }
     }
@@ -1032,6 +1039,14 @@ public class DirectoryFragment extends Fragment
         return null;
     }
 
+    private @Nullable DocumentHolder getDocumentHolder(View v) {
+        RecyclerView.ViewHolder vh = mRecView.getChildViewHolder(v);
+        if (vh instanceof DocumentHolder) {
+            return (DocumentHolder) vh;
+        }
+        return null;
+    }
+
     // TODO: Move to activities when Model becomes activity level object.
     private boolean canSelect(DocumentDetails doc) {
         return canSetSelectionState(doc.getModelId(), true);
diff --git a/src/com/android/documentsui/dirlist/DocumentHolder.java b/src/com/android/documentsui/dirlist/DocumentHolder.java
index b5c1174f5..3015d4264 100644
--- a/src/com/android/documentsui/dirlist/DocumentHolder.java
+++ b/src/com/android/documentsui/dirlist/DocumentHolder.java
@@ -49,6 +49,8 @@ public abstract class DocumentHolder
     protected final Context mContext;
     protected final @ColorInt int mDefaultBgColor;
     protected final @ColorInt int mSelectedBgColor;
+    protected final @ColorInt int mDroppableBgColor;
+    protected final @ColorInt int mNotDroppableBgColor;
 
     protected @Nullable String mModelId;
 
@@ -72,6 +74,9 @@ public abstract class DocumentHolder
 
         mDefaultBgColor = context.getColor(R.color.item_doc_background);
         mSelectedBgColor = context.getColor(R.color.item_doc_background_selected);
+        mDroppableBgColor = context.getColor(R.color.item_doc_droppable_background);
+        mNotDroppableBgColor = context.getColor(R.color.item_doc_not_droppable_background);
+
         mSelectionHotspot = itemView.findViewById(R.id.icon_check);
 
         mDebugContainer = (FrameLayout) itemView.findViewById(R.id.debug_info);
@@ -118,13 +123,24 @@ public abstract class DocumentHolder
      * Highlights the associated item view to indicate it's droppable.
      * @param highlighted
      */
-    public void setDroppableHighlight(boolean highlighted) {
-        // If item is already selected, its droppable highlight should not be changed.
+    public void setDroppableHighlight(boolean droppable) {
+        // If item is already selected, its highlight should not be changed.
+        if (itemView.isActivated()) {
+            return;
+        }
+
+        itemView.setBackgroundColor(droppable ? mDroppableBgColor : mNotDroppableBgColor);
+    }
+
+    /**
+     * Reset the associated item view's droppable background highlight.
+     */
+    public void resetDropHighlight() {
         if (itemView.isActivated()) {
             return;
         }
 
-        itemView.setBackgroundColor(highlighted ? mSelectedBgColor : mDefaultBgColor);
+        itemView.setBackgroundColor(mDefaultBgColor);
     }
 
     public void setEnabled(boolean enabled) {
diff --git a/src/com/android/documentsui/sidebar/RootsFragment.java b/src/com/android/documentsui/sidebar/RootsFragment.java
index 242f5744b..e4cc57cf6 100644
--- a/src/com/android/documentsui/sidebar/RootsFragment.java
+++ b/src/com/android/documentsui/sidebar/RootsFragment.java
@@ -397,7 +397,7 @@ public class RootsFragment extends Fragment implements ItemDragListener.DragHost
     }
 
     @Override
-    public void setDropTargetHighlight(View v, boolean highlight) {
+    public void setDropTargetHighlight(View v, Object localState, boolean highlight) {
         // SpacerView doesn't have DragListener so this view is guaranteed to be a RootItemView.
         RootItemView itemView = (RootItemView) v;
         itemView.setHighlight(highlight);
diff --git a/tests/unit/com/android/documentsui/ItemDragListenerTest.java b/tests/unit/com/android/documentsui/ItemDragListenerTest.java
index 865d8b6c6..71799ac9d 100644
--- a/tests/unit/com/android/documentsui/ItemDragListenerTest.java
+++ b/tests/unit/com/android/documentsui/ItemDragListenerTest.java
@@ -202,7 +202,7 @@ public class ItemDragListenerTest {
         private View mLastEnteredView;
 
         @Override
-        public void setDropTargetHighlight(View v, boolean highlight) {
+        public void setDropTargetHighlight(View v, Object localState, boolean highlight) {
             mHighlightedView = highlight ? v : null;
         }
 
diff --git a/tests/unit/com/android/documentsui/dirlist/DragScrollListenerTest.java b/tests/unit/com/android/documentsui/dirlist/DragScrollListenerTest.java
index fc5933a3e..3a0cc4c08 100644
--- a/tests/unit/com/android/documentsui/dirlist/DragScrollListenerTest.java
+++ b/tests/unit/com/android/documentsui/dirlist/DragScrollListenerTest.java
@@ -188,7 +188,7 @@ public class DragScrollListenerTest {
     private static class TestDragHost implements ItemDragListener.DragHost {
 
         @Override
-        public void setDropTargetHighlight(View v, boolean highlight) {
+        public void setDropTargetHighlight(View v, Object localState, boolean highlight) {
         }
 
         @Override