Wrap up the stable ID refactor.

- Rationalize band selection: make it internally a range selection
  operation, that translates positions to IDs only when updating the
  Selection.
- Clean up TODOs and comments.
- Fix selection adjustment when things are removed from the view.

Change-Id: If917eb9dd18e755c5a0ce83c84409902c4ef3d2e

5 files changed, 158 insertions, 91 deletions

diff --git a/packages/DocumentsUI/src/com/android/documentsui/dirlist/DirectoryFragment.java b/packages/DocumentsUI/src/com/android/documentsui/dirlist/DirectoryFragment.java
index ef7169363299..5eef9b7485db 100644
--- a/packages/DocumentsUI/src/com/android/documentsui/dirlist/DirectoryFragment.java
+++ b/packages/DocumentsUI/src/com/android/documentsui/dirlist/DirectoryFragment.java
@@ -1003,10 +1003,9 @@ public class DirectoryFragment extends Fragment {
         static private final String TAG = "DocumentsAdapter";
         private final Context mContext;
         /**
-         * Map of model IDs to adapter positions. This is the data structure that determines what
-         * shows up in the UI, and where.
+         * An ordered list of model IDs. This is the data structure that determines what shows up in
+         * the UI, and where.
          */
-        // TODO(stable-id): need to keep this up-to-date when items are added/removed
         private List<String> mModelIds = new ArrayList<>();
 
         public DocumentsAdapter(Context context) {
@@ -1225,7 +1224,6 @@ public class DirectoryFragment extends Fragment {
 
         @Override
         public void onModelUpdate(Model model) {
-            // TODO(stable-id): Sort model IDs, categorize by dir/file, etc
             mModelIds = Lists.newArrayList(model.getModelIds());
         }
 
diff --git a/packages/DocumentsUI/src/com/android/documentsui/dirlist/MultiSelectManager.java b/packages/DocumentsUI/src/com/android/documentsui/dirlist/MultiSelectManager.java
index 83c82947626f..43023e13eebe 100644
--- a/packages/DocumentsUI/src/com/android/documentsui/dirlist/MultiSelectManager.java
+++ b/packages/DocumentsUI/src/com/android/documentsui/dirlist/MultiSelectManager.java
@@ -30,6 +30,8 @@ import android.support.v7.widget.GridLayoutManager;
 import android.support.v7.widget.RecyclerView;
 import android.util.Log;
 import android.util.SparseArray;
+import android.util.SparseBooleanArray;
+import android.util.SparseIntArray;
 import android.view.GestureDetector;
 import android.view.KeyEvent;
 import android.view.MotionEvent;
@@ -40,6 +42,7 @@ import com.android.documentsui.Events.MotionInputEvent;
 import com.android.documentsui.R;
 
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
@@ -140,21 +143,13 @@ public final class MultiSelectManager implements View.OnKeyListener {
         mEnvironment.registerDataObserver(
                 new RecyclerView.AdapterDataObserver() {
 
-                    private List<String> mModelIds = new ArrayList<>();
+                    private List<String> mModelIds;
 
                     @Override
                     public void onChanged() {
-                        // TODO(stable-id): This is causing b/22765812
+                        // TODO: This is causing b/22765812
                         mSelection.clear();
-
-                        // TODO(stable-id): Improve this. It's currently super-inefficient,
-                        // performing a bunch of lookups and inserting into a List. Maybe just add
-                        // another method to the SelectionEnvironment to just grab the whole list at
-                        // once.
-                        mModelIds.clear();
-                        for (int i = 0; i < mEnvironment.getItemCount(); ++i) {
-                            mModelIds.add(mEnvironment.getModelIdFromAdapterPosition(i));
-                        }
+                        mModelIds = mEnvironment.getModelIds();
                     }
 
                     @Override
@@ -172,14 +167,10 @@ public final class MultiSelectManager implements View.OnKeyListener {
                     public void onItemRangeRemoved(int startPosition, int itemCount) {
                         checkState(startPosition >= 0);
                         checkState(itemCount > 0);
+
                         mSelection.cancelProvisionalSelection();
-                        int endPosition = startPosition + itemCount;
                         // Remove any disappeared IDs from the selection.
-                        for (int i = startPosition; i < endPosition; i++) {
-                            String id = mModelIds.get(i);
-                            mSelection.remove(id);
-                            mModelIds.remove(i);
-                        }
+                        mSelection.intersect(mModelIds);
                     }
 
                     @Override
@@ -731,6 +722,14 @@ public final class MultiSelectManager implements View.OnKeyListener {
             mTotalSelection.clear();
         }
 
+        /**
+         * Trims this selection to be the intersection of itself with the set of given IDs.
+         */
+        public void intersect(Collection<String> ids) {
+            mSavedSelection.retainAll(ids);
+            mTotalSelection.retainAll(ids);
+        }
+
         @VisibleForTesting
         void copyFrom(Selection source) {
             mSavedSelection = new HashSet<>(source.mSavedSelection);
@@ -794,6 +793,7 @@ public final class MultiSelectManager implements View.OnKeyListener {
         void removeCallback(Runnable r);
         Point createAbsolutePoint(Point relativePoint);
         Rect getAbsoluteRectForChildViewAt(int index);
+        int getAdapterPositionAt(int index);
         int getAdapterPositionForChildView(View view);
         int getColumnCount();
         int getRowCount();
@@ -801,9 +801,8 @@ public final class MultiSelectManager implements View.OnKeyListener {
         int getVisibleChildCount();
         void focusItem(int position);
         String getModelIdFromAdapterPosition(int position);
-        String getModelIdAt(int index);
-        String getModelIdForChildView(View view);
         int getItemCount();
+        List<String> getModelIds();
         void notifyItemChanged(String id, String selectionChangedMarker);
         void registerDataObserver(RecyclerView.AdapterDataObserver observer);
     }
@@ -833,14 +832,8 @@ public final class MultiSelectManager implements View.OnKeyListener {
         }
 
         @Override
-        public String getModelIdForChildView(View view) {
-            if (view.getParent() == mView) {
-                RecyclerView.ViewHolder vh = mView.getChildViewHolder(view);
-                if (vh instanceof DirectoryFragment.DocumentHolder) {
-                    return ((DirectoryFragment.DocumentHolder) vh).modelId;
-                }
-            }
-            return null;
+        public int getAdapterPositionAt(int index) {
+            return getAdapterPositionForChildView(mView.getChildAt(index));
         }
 
         @Override
@@ -849,11 +842,6 @@ public final class MultiSelectManager implements View.OnKeyListener {
         }
 
         @Override
-        public String getModelIdAt(int index) {
-            return getModelIdForChildView(mView.getChildAt(index));
-        }
-
-        @Override
         public void addOnScrollListener(RecyclerView.OnScrollListener listener) {
             mView.addOnScrollListener(listener);
         }
@@ -997,6 +985,11 @@ public final class MultiSelectManager implements View.OnKeyListener {
         public void registerDataObserver(RecyclerView.AdapterDataObserver observer) {
             mAdapter.registerAdapterDataObserver(observer);
         }
+
+        @Override
+        public List<String> getModelIds() {
+            return mAdapter.getModelIds();
+        }
     }
 
     public interface Callback {
@@ -1179,15 +1172,14 @@ public final class MultiSelectManager implements View.OnKeyListener {
             mEnvironment.hideBand();
             mSelection.applyProvisionalSelection();
             mModel.endSelection();
-            String firstSelected = mModel.getItemNearestOrigin();
-            if (!mSelection.contains(firstSelected)) {
+            int firstSelected = mModel.getPositionNearestOrigin();
+            if (!mSelection.contains(mEnvironment.getModelIdFromAdapterPosition(firstSelected))) {
                 Log.w(TAG, "First selected by band is NOT in selection!");
                 // Sadly this is really happening. Need to figure out what's going on.
-            } else if (firstSelected != null) {
-                // TODO(stable-id): firstSelected should really be lastSelected, we want to anchor the
-                // range where the mouse-up occurred. Also figure out how to translate the model ID
-                // into a position.
-                // setSelectionRangeBegin(firstSelected);
+            } else if (firstSelected != NOT_SET) {
+                // TODO: firstSelected should really be lastSelected, we want to anchor the item
+                // where the mouse-up occurred.
+                setSelectionRangeBegin(firstSelected);
             }
 
             mModel = null;
@@ -1349,7 +1341,7 @@ public final class MultiSelectManager implements View.OnKeyListener {
         // by their y-offset. For example, if the first column of the view starts at an x-value of 5,
         // mColumns.get(5) would return an array of positions in that column. Within that array, the
         // value for key y is the adapter position for the item whose y-offset is y.
-        private final SparseArray<SparseArray<String>> mColumns = new SparseArray<>();
+        private final SparseArray<SparseIntArray> mColumns = new SparseArray<>();
 
         // List of limits along the x-axis (columns).
         // This list is sorted from furthest left to furthest right.
@@ -1360,7 +1352,7 @@ public final class MultiSelectManager implements View.OnKeyListener {
         private final List<Limits> mRowBounds = new ArrayList<>();
 
         // The adapter positions which have been recorded so far.
-        private final Set<String> mKnownIds = new HashSet<>();
+        private final SparseBooleanArray mKnownPositions = new SparseBooleanArray();
 
         // Array passed to registered OnSelectionChangedListeners. One array is created and reused
         // throughout the lifetime of the object.
@@ -1377,7 +1369,7 @@ public final class MultiSelectManager implements View.OnKeyListener {
 
         // Tracks where the band select originated from. This is used to determine where selections
         // should expand from when Shift+click is used.
-        private String mItemNearestOrigin = null;
+        private int mPositionNearestOrigin = NOT_SET;
 
         GridModel(SelectionEnvironment helper) {
             mHelper = helper;
@@ -1434,8 +1426,8 @@ public final class MultiSelectManager implements View.OnKeyListener {
          * @return The adapter position for the item nearest the origin corresponding to the latest
          *         band select operation, or NOT_SET if the selection did not cover any items.
          */
-        String getItemNearestOrigin() {
-            return mItemNearestOrigin;
+        int getPositionNearestOrigin() {
+            return mPositionNearestOrigin;
         }
 
         @Override
@@ -1455,10 +1447,10 @@ public final class MultiSelectManager implements View.OnKeyListener {
          */
         private void recordVisibleChildren() {
             for (int i = 0; i < mHelper.getVisibleChildCount(); i++) {
-                String modelId = mHelper.getModelIdAt(i);
-                if (!mKnownIds.contains(modelId)) {
-                    mKnownIds.add(modelId);
-                    recordItemData(mHelper.getAbsoluteRectForChildViewAt(i), modelId);
+                int adapterPosition = mHelper.getAdapterPositionAt(i);
+                if (!mKnownPositions.get(adapterPosition)) {
+                    mKnownPositions.put(adapterPosition, true);
+                    recordItemData(mHelper.getAbsoluteRectForChildViewAt(i), adapterPosition);
                 }
             }
         }
@@ -1468,7 +1460,7 @@ public final class MultiSelectManager implements View.OnKeyListener {
          * @param absoluteChildRect The absolute rectangle for the child view being processed.
          * @param adapterPosition The position of the child view being processed.
          */
-        private void recordItemData(Rect absoluteChildRect, String modelId) {
+        private void recordItemData(Rect absoluteChildRect, int adapterPosition) {
             if (mColumnBounds.size() != mHelper.getColumnCount()) {
                 // If not all x-limits have been recorded, record this one.
                 recordLimits(
@@ -1481,12 +1473,12 @@ public final class MultiSelectManager implements View.OnKeyListener {
                         mRowBounds, new Limits(absoluteChildRect.top, absoluteChildRect.bottom));
             }
 
-            SparseArray<String> columnList = mColumns.get(absoluteChildRect.left);
+            SparseIntArray columnList = mColumns.get(absoluteChildRect.left);
             if (columnList == null) {
-                columnList = new SparseArray<>();
+                columnList = new SparseIntArray();
                 mColumns.put(absoluteChildRect.left, columnList);
             }
-            columnList.put(absoluteChildRect.top, modelId);
+            columnList.put(absoluteChildRect.top, adapterPosition);
         }
 
         /**
@@ -1523,7 +1515,7 @@ public final class MultiSelectManager implements View.OnKeyListener {
                 updateSelection(computeBounds());
             } else {
                 mSelection.clear();
-                mItemNearestOrigin = null;
+                mPositionNearestOrigin = NOT_SET;
             }
         }
 
@@ -1552,11 +1544,11 @@ public final class MultiSelectManager implements View.OnKeyListener {
                 columnEndIndex = i;
             }
 
-            SparseArray<String> firstColumn =
+            SparseIntArray firstColumn =
                     mColumns.get(mColumnBounds.get(columnStartIndex).lowerLimit);
             int rowStartIndex = firstColumn.indexOfKey(rect.top);
             if (rowStartIndex < 0) {
-                mItemNearestOrigin = null;
+                mPositionNearestOrigin = NOT_SET;
                 return;
             }
 
@@ -1577,15 +1569,20 @@ public final class MultiSelectManager implements View.OnKeyListener {
                 int columnStartIndex, int columnEndIndex, int rowStartIndex, int rowEndIndex) {
             mSelection.clear();
             for (int column = columnStartIndex; column <= columnEndIndex; column++) {
-                SparseArray<String> items = mColumns.get(mColumnBounds.get(column).lowerLimit);
+                SparseIntArray items = mColumns.get(mColumnBounds.get(column).lowerLimit);
                 for (int row = rowStartIndex; row <= rowEndIndex; row++) {
-                    String id = items.get(items.keyAt(row));
-                    mSelection.add(id);
+                    int position = items.get(items.keyAt(row));
+                    String id = mHelper.getModelIdFromAdapterPosition(position);
+                    if (id != null) {
+                        // The adapter inserts items for UI layout purposes that aren't associated
+                        // with files.  Those will have a null model ID.  Don't select them.
+                        mSelection.add(id);
+                    }
                     if (isPossiblePositionNearestOrigin(column, columnStartIndex, columnEndIndex,
                             row, rowStartIndex, rowEndIndex)) {
                         // If this is the position nearest the origin, record it now so that it
                         // can be returned by endSelection() later.
-                        mItemNearestOrigin = id;
+                        mPositionNearestOrigin = position;
                     }
                 }
             }
diff --git a/packages/DocumentsUI/tests/src/com/android/documentsui/dirlist/MultiSelectManager_GridModelTest.java b/packages/DocumentsUI/tests/src/com/android/documentsui/dirlist/MultiSelectManager_GridModelTest.java
index 153f58b69992..d6e8b5518223 100644
--- a/packages/DocumentsUI/tests/src/com/android/documentsui/dirlist/MultiSelectManager_GridModelTest.java
+++ b/packages/DocumentsUI/tests/src/com/android/documentsui/dirlist/MultiSelectManager_GridModelTest.java
@@ -16,17 +16,19 @@
 
 package com.android.documentsui.dirlist;
 
+import static com.android.documentsui.dirlist.MultiSelectManager.GridModel.NOT_SET;
+
 import android.graphics.Point;
 import android.graphics.Rect;
 import android.support.v7.widget.RecyclerView.AdapterDataObserver;
 import android.support.v7.widget.RecyclerView.OnScrollListener;
 import android.test.AndroidTestCase;
 import android.test.suitebuilder.annotation.SmallTest;
-import android.util.Log;
 import android.view.View;
 
 import com.android.documentsui.dirlist.MultiSelectManager.GridModel;
 
+import java.util.List;
 import java.util.Set;
 
 @SmallTest
@@ -66,7 +68,7 @@ public class MultiSelectManager_GridModelTest extends AndroidTestCase {
         model.startSelection(new Point(0, 10));
         model.resizeSelection(new Point(1, 11));
         assertSelected();
-        assertEquals(null, model.getItemNearestOrigin());
+        assertEquals(NOT_SET, model.getPositionNearestOrigin());
     }
 
     public void testSelectionRightOfItems() {
@@ -74,7 +76,7 @@ public class MultiSelectManager_GridModelTest extends AndroidTestCase {
         model.startSelection(new Point(viewWidth - 1, 10));
         model.resizeSelection(new Point(viewWidth - 2, 11));
         assertSelected();
-        assertEquals(null, model.getItemNearestOrigin());
+        assertEquals(NOT_SET, model.getPositionNearestOrigin());
     }
 
     public void testSelectionAboveItems() {
@@ -82,7 +84,7 @@ public class MultiSelectManager_GridModelTest extends AndroidTestCase {
         model.startSelection(new Point(10, 0));
         model.resizeSelection(new Point(11, 1));
         assertSelected();
-        assertEquals(null, model.getItemNearestOrigin());
+        assertEquals(NOT_SET, model.getPositionNearestOrigin());
     }
 
     public void testSelectionBelowItems() {
@@ -90,7 +92,7 @@ public class MultiSelectManager_GridModelTest extends AndroidTestCase {
         model.startSelection(new Point(10, VIEWPORT_HEIGHT - 1));
         model.resizeSelection(new Point(11, VIEWPORT_HEIGHT - 2));
         assertSelected();
-        assertEquals(null, model.getItemNearestOrigin());
+        assertEquals(NOT_SET, model.getPositionNearestOrigin());
     }
 
     public void testVerticalSelectionBetweenItems() {
@@ -98,7 +100,7 @@ public class MultiSelectManager_GridModelTest extends AndroidTestCase {
         model.startSelection(new Point(106, 0));
         model.resizeSelection(new Point(107, 200));
         assertSelected();
-        assertEquals(null, model.getItemNearestOrigin());
+        assertEquals(NOT_SET, model.getPositionNearestOrigin());
     }
 
     public void testHorizontalSelectionBetweenItems() {
@@ -106,7 +108,7 @@ public class MultiSelectManager_GridModelTest extends AndroidTestCase {
         model.startSelection(new Point(0, 105));
         model.resizeSelection(new Point(200, 106));
         assertSelected();
-        assertEquals(null, model.getItemNearestOrigin());
+        assertEquals(NOT_SET, model.getPositionNearestOrigin());
     }
 
     public void testGrowingAndShrinkingSelection() {
@@ -136,7 +138,7 @@ public class MultiSelectManager_GridModelTest extends AndroidTestCase {
         assertSelected(0);
         model.resizeSelection(new Point(0, 0));
         assertSelected();
-        assertEquals(null, model.getItemNearestOrigin());
+        assertEquals(NOT_SET, model.getPositionNearestOrigin());
     }
 
     public void testSelectionMovingAroundOrigin() {
@@ -150,7 +152,7 @@ public class MultiSelectManager_GridModelTest extends AndroidTestCase {
         assertSelected(8, 9, 12, 13);
         model.resizeSelection(new Point(viewWidth - 1, 420));
         assertSelected(10, 11, 14, 15);
-        assertEquals("10", model.getItemNearestOrigin());
+        assertEquals(10, model.getPositionNearestOrigin());
     }
 
     public void testScrollingBandSelect() {
@@ -168,7 +170,7 @@ public class MultiSelectManager_GridModelTest extends AndroidTestCase {
         assertSelected(0, 1, 4, 5, 8, 9, 12, 13, 16, 17);
         model.resizeSelection(new Point(100, VIEWPORT_HEIGHT - 1));
         assertSelected(0, 4, 8, 12, 16);
-        assertEquals("0", model.getItemNearestOrigin());
+        assertEquals(0, model.getPositionNearestOrigin());
     }
 
     private static void assertSelected(int... selectedPositions) {
@@ -243,6 +245,11 @@ public class MultiSelectManager_GridModelTest extends AndroidTestCase {
         }
 
         @Override
+        public int getAdapterPositionAt(int index) {
+            return index + mNumColumns * (getFirstVisibleRowIndex());
+        }
+
+        @Override
         public Rect getAbsoluteRectForChildViewAt(int index) {
             int adapterPosition = (getFirstVisibleRowIndex() * mNumColumns) + index;
             int rowIndex = adapterPosition / mNumColumns;
@@ -322,19 +329,13 @@ public class MultiSelectManager_GridModelTest extends AndroidTestCase {
         }
 
         @Override
-        public String getModelIdAt(int index) {
-            int firstVisibleChildIndex = getFirstVisibleRowIndex() * mNumColumns;
-            return Integer.toString(firstVisibleChildIndex + index);
-        }
-
-        @Override
-        public String getModelIdForChildView(View view) {
-            throw new UnsupportedOperationException();
+        public int getItemCount() {
+            return mNumChildren;
         }
 
         @Override
-        public int getItemCount() {
-            return mNumChildren;
+        public List<String> getModelIds() {
+            return null;
         }
 
         @Override
diff --git a/packages/DocumentsUI/tests/src/com/android/documentsui/dirlist/MultiSelectManager_SelectionTest.java b/packages/DocumentsUI/tests/src/com/android/documentsui/dirlist/MultiSelectManager_SelectionTest.java
index 7c36d63a1777..444b2dc8e383 100644
--- a/packages/DocumentsUI/tests/src/com/android/documentsui/dirlist/MultiSelectManager_SelectionTest.java
+++ b/packages/DocumentsUI/tests/src/com/android/documentsui/dirlist/MultiSelectManager_SelectionTest.java
@@ -20,6 +20,10 @@ import android.test.AndroidTestCase;
 import android.test.suitebuilder.annotation.SmallTest;
 
 import com.android.documentsui.dirlist.MultiSelectManager.Selection;
+import com.google.common.collect.Sets;
+
+import java.util.HashSet;
+import java.util.Set;
 
 @SmallTest
 public class MultiSelectManager_SelectionTest extends AndroidTestCase {
@@ -100,6 +104,72 @@ public class MultiSelectManager_SelectionTest extends AndroidTestCase {
         assertFalse(selection.equals(other));
     }
 
+    public void testIntersection_empty0() {
+        Selection testSelection = new Selection();
+        testSelection.intersect(new HashSet<String>());
+        assertTrue(testSelection.isEmpty());
+    }
+
+    public void testIntersection_empty1() {
+        Selection testSelection = new Selection();
+        testSelection.intersect(Sets.newHashSet("foo"));
+        assertTrue(testSelection.isEmpty());
+    }
+
+    public void testIntersection_empty2() {
+        assertFalse(selection.isEmpty());
+        selection.intersect(new HashSet<String>());
+        assertTrue(selection.isEmpty());
+    }
+
+    public void testIntersection_exclusive() {
+        String[] ids0 = new String[]{"foo", "bar", "baz"};
+        String[] ids1 = new String[]{"0", "1", "2"};
+
+        Selection testSelection = new Selection();
+        testSelection.add(ids0[0]);
+        testSelection.add(ids0[1]);
+        testSelection.add(ids0[2]);
+
+        Set<String> set = Sets.newHashSet(ids1);
+        testSelection.intersect(set);
+
+        assertTrue(testSelection.isEmpty());
+    }
+
+    public void testIntersection_subset() {
+        String[] ids0 = new String[]{"foo", "bar", "baz"};
+        String[] ids1 = new String[]{"0", "baz", "1", "foo", "2"};
+
+        Selection testSelection = new Selection();
+        testSelection.add(ids0[0]);
+        testSelection.add(ids0[1]);
+        testSelection.add(ids0[2]);
+
+        testSelection.intersect(Sets.newHashSet(ids1));
+
+        assertTrue(testSelection.contains("foo"));
+        assertFalse(testSelection.contains("bar"));
+        assertTrue(testSelection.contains("baz"));
+    }
+
+    public void testIntersection_all() {
+        String[] ids0 = new String[]{"foo", "bar", "baz"};
+        String[] ids1 = new String[]{"0", "baz", "1", "foo", "2", "bar"};
+
+        Selection testSelection = new Selection();
+        testSelection.add(ids0[0]);
+        testSelection.add(ids0[1]);
+        testSelection.add(ids0[2]);
+
+        Selection control = new Selection();
+        control.copyFrom(testSelection);
+
+        testSelection.intersect(Sets.newHashSet(ids1));
+
+        assertTrue(testSelection.equals(control));
+    }
+
     private void assertContains(String id) {
         String err = String.format("Selection %s does not contain %s", selection, id);
         assertTrue(err, selection.contains(id));
diff --git a/packages/DocumentsUI/tests/src/com/android/documentsui/dirlist/TestSelectionEnvironment.java b/packages/DocumentsUI/tests/src/com/android/documentsui/dirlist/TestSelectionEnvironment.java
index 9608e7e59a7f..68056442a4bc 100644
--- a/packages/DocumentsUI/tests/src/com/android/documentsui/dirlist/TestSelectionEnvironment.java
+++ b/packages/DocumentsUI/tests/src/com/android/documentsui/dirlist/TestSelectionEnvironment.java
@@ -25,6 +25,7 @@ import android.view.View;
 import com.android.documentsui.dirlist.MultiSelectManager.SelectionEnvironment;
 
 import java.util.List;
+import java.util.Set;
 
 public class TestSelectionEnvironment implements SelectionEnvironment {
 
@@ -82,6 +83,11 @@ public class TestSelectionEnvironment implements SelectionEnvironment {
     }
 
     @Override
+    public int getAdapterPositionAt(int index) {
+        return 0;
+    }
+
+    @Override
     public int getAdapterPositionForChildView(View view) {
         return 0;
     }
@@ -116,21 +122,16 @@ public class TestSelectionEnvironment implements SelectionEnvironment {
     }
 
     @Override
-    public String getModelIdAt(int index) {
-        return null;
+    public int getItemCount() {
+        return mItems.size();
     }
 
     @Override
-    public String getModelIdForChildView(View view) {
+    public List<String> getModelIds() {
         return null;
     }
 
     @Override
-    public int getItemCount() {
-        return mItems.size();
-    }
-
-    @Override
     public void notifyItemChanged(String id, String selectionChangedMarker) {
     }