Updated recyclerview-selection: to version 1.1.0-alpha05

app/build.gradle

@@ -134,7 +134,7 @@ dependencies {
     // https://mvnrepository.com/artifact/androidx.recyclerview/recyclerview
     // https://mvnrepository.com/artifact/androidx.recyclerview/recyclerview-selection
     implementation "androidx.recyclerview:recyclerview:$recyclerview_version"
-    //implementation "androidx.recyclerview:recyclerview-selection:1.1.0-alpha01"
+    //implementation "androidx.recyclerview:recyclerview-selection:1.1.0-alpha05"
 
     // https://mvnrepository.com/artifact/androidx.coordinatorlayout/coordinatorlayout
     implementation "androidx.coordinatorlayout:coordinatorlayout:$coordinatorlayout_version"

app/src/main/java/androidx/recyclerview/selection/DefaultSelectionTracker.java

@@ -348,7 +348,7 @@ public class DefaultSelectionTracker<K> extends SelectionTracker<K> {
     }
 
     @Override
-    AdapterDataObserver getAdapterDataObserver() {
+    protected AdapterDataObserver getAdapterDataObserver() {
         return mAdapterObserver;
     }
 

app/src/main/java/androidx/recyclerview/selection/GestureSelectionHelper.java

@@ -19,7 +19,6 @@ package androidx.recyclerview.selection;
 import static androidx.core.util.Preconditions.checkArgument;
 import static androidx.core.util.Preconditions.checkState;
 
-import android.graphics.Point;
 import android.util.Log;
 import android.view.MotionEvent;
 import android.view.View;
@@ -27,6 +26,7 @@ import android.view.View;
 import androidx.annotation.NonNull;
 import androidx.annotation.VisibleForTesting;
 import androidx.core.view.ViewCompat;
+import androidx.recyclerview.selection.SelectionTracker.SelectionPredicate;
 import androidx.recyclerview.widget.RecyclerView;
 import androidx.recyclerview.widget.RecyclerView.OnItemTouchListener;
 
@@ -41,12 +41,11 @@ final class GestureSelectionHelper implements OnItemTouchListener {
     private static final String TAG = "GestureSelectionHelper";
 
     private final SelectionTracker<?> mSelectionMgr;
-    private final ItemDetailsLookup<?> mDetailsLookup;
+    private final SelectionTracker.SelectionPredicate<?> mSelectionPredicate;
     private final AutoScroller mScroller;
     private final ViewDelegate mView;
     private final OperationMonitor mLock;
 
-    private int mLastStartedItemPos = RecyclerView.NO_POSITION;
     private boolean mStarted = false;
 
     /**
@@ -55,19 +54,19 @@ final class GestureSelectionHelper implements OnItemTouchListener {
      */
     GestureSelectionHelper(
             @NonNull SelectionTracker<?> selectionTracker,
-            @NonNull ItemDetailsLookup<?> detailsLookup,
+            @NonNull SelectionPredicate<?> selectionPredicate,
             @NonNull ViewDelegate view,
             @NonNull AutoScroller scroller,
             @NonNull OperationMonitor lock) {
 
         checkArgument(selectionTracker != null);
-        checkArgument(detailsLookup != null);
+        checkArgument(selectionPredicate != null);
         checkArgument(view != null);
         checkArgument(scroller != null);
         checkArgument(lock != null);
 
         mSelectionMgr = selectionTracker;
-        mDetailsLookup = detailsLookup;
+        mSelectionPredicate = selectionPredicate;
         mView = view;
         mScroller = scroller;
         mLock = lock;
@@ -78,16 +77,9 @@ final class GestureSelectionHelper implements OnItemTouchListener {
      */
     void start() {
         checkState(!mStarted);
-        // See: b/70518185. It appears start() is being called via onLongPress
-        // even though we never received an intial handleInterceptedDownEvent
-        // where we would usually initialize mLastStartedItemPos.
-        if (mLastStartedItemPos == RecyclerView.NO_POSITION) {
-            Log.w(TAG, "Illegal state. Can't start without valid mLastStartedItemPos.");
-            return;
-        }
 
         // Partner code in MotionInputHandler ensures items
-        // are selected and range established prior to
+        // are selected and range anchor initialized prior to
         // start being called.
         // Verify the truth of that statement here
         // to make the implicit coupling less of a time bomb.
@@ -102,20 +94,14 @@ final class GestureSelectionHelper implements OnItemTouchListener {
     @Override
     /** @hide */
     public boolean onInterceptTouchEvent(@NonNull RecyclerView unused, @NonNull MotionEvent e) {
-        if (MotionEvents.isMouseEvent(e)) {
+        switch (e.getActionMasked()) {
-            if (Shared.DEBUG) Log.w(TAG, "Unexpected Mouse event. Check configuration.");
+            case MotionEvent.ACTION_MOVE:
-        }
+            case MotionEvent.ACTION_UP:
-
+            case MotionEvent.ACTION_CANCEL:
-        // TODO(b/109808552): It seems that mLastStartedItemPos should likely be set as a method
+                return mStarted;
-        // parameter in start().
+            default:
-        if (e.getActionMasked() == MotionEvent.ACTION_DOWN) {
+                return false;
-            if (mDetailsLookup.getItemDetails(e) != null) {
-                mLastStartedItemPos = mView.getItemUnder(e);
-            }
         }
-
-        // See handleTouch(MotionEvent) javadoc for explanation as to why this is correct.
-        return handleTouch(e);
     }
 
     @Override
@@ -146,6 +132,14 @@ final class GestureSelectionHelper implements OnItemTouchListener {
             return false;
         }
 
+        if (!mSelectionMgr.isRangeActive()) {
+            Log.e(TAG,
+                    "Internal state of GestureSelectionHelper out of sync w/ SelectionTracker "
+                            + "(isRangeActive is false). Ignoring event and resetting state.");
+            endSelection();
+            return false;
+        }
+
         switch (e.getActionMasked()) {
             case MotionEvent.ACTION_MOVE:
                 handleMoveEvent(e);
@@ -172,9 +166,6 @@ final class GestureSelectionHelper implements OnItemTouchListener {
     private void handleUpEvent() {
         mSelectionMgr.mergeProvisionalSelection();
         endSelection();
-        if (mLastStartedItemPos != RecyclerView.NO_POSITION) {
-            mSelectionMgr.startRange(mLastStartedItemPos);
-        }
     }
 
     // Called when ACTION_CANCEL event is to be handled.
@@ -188,7 +179,6 @@ final class GestureSelectionHelper implements OnItemTouchListener {
     private void endSelection() {
         checkState(mStarted);
 
-        mLastStartedItemPos = RecyclerView.NO_POSITION;
         mStarted = false;
         mScroller.reset();
         mLock.stop();
@@ -197,14 +187,12 @@ final class GestureSelectionHelper implements OnItemTouchListener {
     // Call when an intercepted ACTION_MOVE event is passed down.
     // At this point, we are sure user wants to gesture multi-select.
     private void handleMoveEvent(@NonNull MotionEvent e) {
-        Point lastInterceptedPoint = MotionEvents.getOrigin(e);
-
         int lastGlidedItemPos = mView.getLastGlidedItemPosition(e);
-        if (lastGlidedItemPos != RecyclerView.NO_POSITION) {
+        if (mSelectionPredicate.canSetStateAtPosition(lastGlidedItemPos, true)) {
             extendSelection(lastGlidedItemPos);
         }
 
-        mScroller.scroll(lastInterceptedPoint);
+        mScroller.scroll(MotionEvents.getOrigin(e));
     }
 
     // It's possible for events to go over the top/bottom of the RecyclerView.
@@ -232,14 +220,14 @@ final class GestureSelectionHelper implements OnItemTouchListener {
      */
     static GestureSelectionHelper create(
             @NonNull SelectionTracker<?> selectionMgr,
-            @NonNull ItemDetailsLookup<?> detailsLookup,
+            @NonNull SelectionPredicate<?> selectionPredicate,
             @NonNull RecyclerView recyclerView,
             @NonNull AutoScroller scroller,
             @NonNull OperationMonitor lock) {
 
         return new GestureSelectionHelper(
                 selectionMgr,
-                detailsLookup,
+                selectionPredicate,
                 new RecyclerViewDelegate(recyclerView),
                 scroller,
                 lock);

app/src/main/java/androidx/recyclerview/selection/GridModel.java

@@ -33,7 +33,7 @@ import androidx.recyclerview.widget.RecyclerView.OnScrollListener;
 
 import java.util.ArrayList;
 import java.util.Collections;
-import java.util.HashSet;
+import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Set;
 
@@ -84,7 +84,7 @@ final class GridModel<K> {
 
     // Array passed to registered OnSelectionChangedListeners. One array is created and reused
     // throughout the lifetime of the object.
-    private final Set<K> mSelection = new HashSet<>();
+    private final Set<K> mSelection = new LinkedHashSet<>();
 
     // The current pointer (in absolute positioning from the top of the view).
     private Point mPointer;
@@ -259,7 +259,7 @@ final class GridModel<K> {
     private void updateModel() {
         RelativePoint old = mRelPointer;
         mRelPointer = createRelativePoint(mPointer);
-        if (old != null && mRelPointer.equals(old)) {
+        if (mRelPointer.equals(old)) {
             return;
         }
 

app/src/main/java/androidx/recyclerview/selection/ItemDetailsLookup.java

@@ -16,10 +16,13 @@
 
 package androidx.recyclerview.selection;
 
+import static androidx.annotation.RestrictTo.Scope.LIBRARY_GROUP;
+
 import android.view.MotionEvent;
 
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
+import androidx.annotation.RestrictTo;
 import androidx.recyclerview.widget.RecyclerView;
 
 /**
@@ -67,8 +70,10 @@ public abstract class ItemDetailsLookup<K> {
 
     /**
      * @return true if there is an item w/ a stable ID at the event coordinates.
+     * @hide
      */
-    final boolean overItemWithSelectionKey(@NonNull MotionEvent e) {
+    @RestrictTo(LIBRARY_GROUP)
+    protected boolean overItemWithSelectionKey(@NonNull MotionEvent e) {
         return overItem(e) && hasSelectionKey(getItemDetails(e));
     }
 

app/src/main/java/androidx/recyclerview/selection/MotionEvents.java

@@ -33,18 +33,10 @@ final class MotionEvents {
         return e.getToolType(0) == MotionEvent.TOOL_TYPE_MOUSE;
     }
 
-    static boolean isTouchEvent(@NonNull MotionEvent e) {
-        return e.getToolType(0) == MotionEvent.TOOL_TYPE_FINGER;
-    }
-
     static boolean isActionMove(@NonNull MotionEvent e) {
         return e.getActionMasked() == MotionEvent.ACTION_MOVE;
     }
 
-    static boolean isActionDown(@NonNull MotionEvent e) {
-        return e.getActionMasked() == MotionEvent.ACTION_DOWN;
-    }
-
     static boolean isActionUp(@NonNull MotionEvent e) {
         return e.getActionMasked() == MotionEvent.ACTION_UP;
     }

app/src/main/java/androidx/recyclerview/selection/MotionInputHandler.java

@@ -88,7 +88,7 @@ abstract class MotionInputHandler<K> extends SimpleOnGestureListener {
         mFocusDelegate.focusItem(details);
     }
 
-    final boolean isRangeExtension(@NonNull MotionEvent e) {
+    final boolean shouldExtendRange(@NonNull MotionEvent e) {
         return MotionEvents.isShiftKeyPressed(e)
                 && mSelectionTracker.isRangeActive()
                 // Without full corpus access we can't reliably implement range

app/src/main/java/androidx/recyclerview/selection/MouseInputHandler.java

@@ -126,7 +126,7 @@ final class MouseInputHandler<K> extends MotionInputHandler<K> {
         checkState(mSelectionTracker.hasSelection());
         checkArgument(item != null);
 
-        if (isRangeExtension(e)) {
+        if (shouldExtendRange(e)) {
             extendSelectionRange(item);
         } else {
             if (shouldClearSelection(e, item)) {

app/src/main/java/androidx/recyclerview/selection/Selection.java

@@ -19,9 +19,9 @@ package androidx.recyclerview.selection;
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 
-import java.util.HashMap;
-import java.util.HashSet;
 import java.util.Iterator;
+import java.util.LinkedHashMap;
+import java.util.LinkedHashSet;
 import java.util.Map;
 import java.util.Set;
 
@@ -65,8 +65,8 @@ public class Selection<K> implements Iterable<K> {
     final Set<K> mProvisionalSelection;
 
     Selection() {
-        mSelection = new HashSet<>();
+        mSelection = new LinkedHashSet<>();
-        mProvisionalSelection = new HashSet<>();
+        mProvisionalSelection = new LinkedHashSet<>();
     }
 
     /**
@@ -74,7 +74,7 @@ public class Selection<K> implements Iterable<K> {
      */
     Selection(@NonNull Set<K> selection) {
         mSelection = selection;
-        mProvisionalSelection = new HashSet<>();
+        mProvisionalSelection = new LinkedHashSet<>();
     }
 
     /**
@@ -117,7 +117,7 @@ public class Selection<K> implements Iterable<K> {
      * @return Map of ids added or removed. Added ids have a value of true, removed are false.
      */
     Map<K, Boolean> setProvisionalSelection(@NonNull Set<K> newSelection) {
-        Map<K, Boolean> delta = new HashMap<>();
+        Map<K, Boolean> delta = new LinkedHashMap<>();
 
         for (K key: mProvisionalSelection) {
             // Mark each item that used to be in the provisional selection
@@ -128,7 +128,7 @@ public class Selection<K> implements Iterable<K> {
         }
 
         for (K key: mSelection) {
-            // Mark each item that used to be in the selection but is unsaved and not in the new
+            // Mark each item that in the selection but is not in the new
             // provisional selection.
             if (!newSelection.contains(key)) {
                 delta.put(key, false);

app/src/main/java/androidx/recyclerview/selection/SelectionTracker.java

@@ -16,6 +16,7 @@
 
 package androidx.recyclerview.selection;
 
+import static androidx.annotation.RestrictTo.Scope.LIBRARY_GROUP;
 import static androidx.core.util.Preconditions.checkArgument;
 
 import android.content.Context;
@@ -28,6 +29,7 @@ import android.view.MotionEvent;
 import androidx.annotation.DrawableRes;
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
+import androidx.annotation.RestrictTo;
 import androidx.recyclerview.widget.RecyclerView;
 import androidx.recyclerview.widget.RecyclerView.AdapterDataObserver;
 import androidx.recyclerview.widget.RecyclerView.OnItemTouchListener;
@@ -177,7 +179,9 @@ public abstract class SelectionTracker<K> {
      */
     public abstract boolean deselect(@NonNull K key);
 
-    abstract AdapterDataObserver getAdapterDataObserver();
+    /** @hide */
+    @RestrictTo(LIBRARY_GROUP)
+    protected abstract AdapterDataObserver getAdapterDataObserver();
 
     /**
      * Attempts to establish a range selection at {@code position}, selecting the item
@@ -186,8 +190,10 @@ public abstract class SelectionTracker<K> {
      * @param position The "anchor" position for the range. Subsequent range operations
      *                 (primarily keyboard and mouse based operations like SHIFT + click)
      *                 work with the established anchor point to define selection ranges.
+     * @hide
      */
-    abstract void startRange(int position);
+    @RestrictTo(LIBRARY_GROUP)
+    public abstract void startRange(int position);
 
     /**
      * Sets the end point for the active range selection.
@@ -200,20 +206,26 @@ public abstract class SelectionTracker<K> {
      * @param position  The new end position for the selection range.
      * @throws IllegalStateException if a range selection is not active. Range selection
      *         must have been started by a call to {@link #startRange(int)}.
+     * @hide
      */
-    abstract void extendRange(int position);
+    @RestrictTo(LIBRARY_GROUP)
+    public abstract void extendRange(int position);
 
     /**
      * Clears an in-progress range selection. Provisional range selection established
      * using {@link #extendProvisionalRange(int)} will be cleared (unless
      * {@link #mergeProvisionalSelection()} is called first.)
+     * @hide
      */
-    abstract void endRange();
+    @RestrictTo(LIBRARY_GROUP)
+    public abstract void endRange();
 
     /**
      * @return Whether or not there is a current range selection active.
+     * @hide
      */
-    abstract boolean isRangeActive();
+    @RestrictTo(LIBRARY_GROUP)
+    public abstract boolean isRangeActive();
 
     /**
      * Establishes the "anchor" at which a selection range begins. This "anchor" is consulted
@@ -223,32 +235,42 @@ public abstract class SelectionTracker<K> {
      * TODO: Reconcile this with startRange. Maybe just docs need to be updated.
      *
      * @param position the anchor position. Must already be selected.
+     * @hide
      */
-    abstract void anchorRange(int position);
+    @RestrictTo(LIBRARY_GROUP)
+    public abstract void anchorRange(int position);
 
     /**
      * Creates a provisional selection from anchor to {@code position}.
      *
      * @param position the end point.
+     * @hide
      */
-    abstract void extendProvisionalRange(int position);
+    @RestrictTo(LIBRARY_GROUP)
+    protected abstract void extendProvisionalRange(int position);
 
     /**
      * Sets the provisional selection, replacing any existing selection.
      * @param newSelection
+     * @hide
      */
-    abstract void setProvisionalSelection(@NonNull Set<K> newSelection);
+    @RestrictTo(LIBRARY_GROUP)
+    protected abstract void setProvisionalSelection(@NonNull Set<K> newSelection);
 
     /**
      * Clears any existing provisional selection
+     * @hide
      */
-    abstract void clearProvisionalSelection();
+    @RestrictTo(LIBRARY_GROUP)
+    protected abstract void clearProvisionalSelection();
 
     /**
      * Converts the provisional selection into primary selection, then clears
      * provisional selection.
+     * @hide
      */
-    abstract void mergeProvisionalSelection();
+    @RestrictTo(LIBRARY_GROUP)
+    protected abstract void mergeProvisionalSelection();
 
     /**
      * Preserves selection, if any. Call this method from Activity#onSaveInstanceState
@@ -689,7 +711,7 @@ public abstract class SelectionTracker<K> {
             // of motions and gestures in order to provide gesture driven selection support
             // when used in conjunction with RecyclerView.
             final GestureSelectionHelper gestureHelper = GestureSelectionHelper.create(
-                    tracker, mDetailsLookup, mRecyclerView, scroller, mMonitor);
+                    tracker, mSelectionPredicate, mRecyclerView, scroller, mMonitor);
 
             // Finally hook the framework up to listening to recycle view events.
             mRecyclerView.addOnItemTouchListener(eventRouter);

app/src/main/java/androidx/recyclerview/selection/StableIdKeyProvider.java

@@ -16,17 +16,18 @@
 
 package androidx.recyclerview.selection;
 
+import static androidx.recyclerview.selection.Shared.DEBUG;
+
+import android.util.Log;
 import android.util.SparseArray;
 import android.view.View;
 
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
+import androidx.collection.LongSparseArray;
 import androidx.recyclerview.widget.RecyclerView;
 import androidx.recyclerview.widget.RecyclerView.OnChildAttachStateChangeListener;
 
-import java.util.HashMap;
-import java.util.Map;
-
 /**
  * An {@link ItemKeyProvider} that provides stable ids by way of cached
  * {@link RecyclerView.Adapter} stable ids. Items enter the cache as they are laid out by
@@ -39,8 +40,10 @@ import java.util.Map;
  */
 public final class StableIdKeyProvider extends ItemKeyProvider<Long> {
 
+    private static final String TAG = "StableIdKeyProvider";
+
     private final SparseArray<Long> mPositionToKey = new SparseArray<>();
-    private final Map<Long, Integer> mKeyToPosition = new HashMap<Long, Integer>();
+    private final LongSparseArray<Integer> mKeyToPosition = new LongSparseArray<>();
     private final RecyclerView mRecyclerView;
 
     /**
@@ -76,6 +79,12 @@ public final class StableIdKeyProvider extends ItemKeyProvider<Long> {
     @SuppressWarnings("WeakerAccess") /* synthetic access */
     void onAttached(@NonNull View view) {
         RecyclerView.ViewHolder holder = mRecyclerView.findContainingViewHolder(view);
+        if (holder == null) {
+            if (DEBUG) {
+                Log.w(TAG, "Unable to find ViewHolder for View. Ignoring onAttached event.");
+            }
+            return;
+        }
         int position = holder.getAdapterPosition();
         long id = holder.getItemId();
         if (position != RecyclerView.NO_POSITION && id != RecyclerView.NO_ID) {
@@ -87,6 +96,12 @@ public final class StableIdKeyProvider extends ItemKeyProvider<Long> {
     @SuppressWarnings("WeakerAccess") /* synthetic access */
     void onDetached(@NonNull View view) {
         RecyclerView.ViewHolder holder = mRecyclerView.findContainingViewHolder(view);
+        if (holder == null) {
+            if (DEBUG) {
+                Log.w(TAG, "Unable to find ViewHolder for View. Ignoring onDetached event.");
+            }
+            return;
+        }
         int position = holder.getAdapterPosition();
         long id = holder.getItemId();
         if (position != RecyclerView.NO_POSITION && id != RecyclerView.NO_ID) {
@@ -102,9 +117,6 @@ public final class StableIdKeyProvider extends ItemKeyProvider<Long> {
 
     @Override
     public int getPosition(@NonNull Long key) {
-        if (mKeyToPosition.containsKey(key)) {
+        return mKeyToPosition.get(key, RecyclerView.NO_POSITION);
-            return mKeyToPosition.get(key);
-        }
-        return RecyclerView.NO_POSITION;
     }
 }

app/src/main/java/androidx/recyclerview/selection/TouchInputHandler.java

@@ -88,7 +88,7 @@ final class TouchInputHandler<K> extends MotionInputHandler<K> {
         }
 
         if (mSelectionTracker.hasSelection()) {
-            if (isRangeExtension(e)) {
+            if (shouldExtendRange(e)) {
                 extendSelectionRange(item);
             } else if (mSelectionTracker.isSelected(item.getSelectionKey())) {
                 mSelectionTracker.deselect(item.getSelectionKey());
@@ -126,32 +126,26 @@ final class TouchInputHandler<K> extends MotionInputHandler<K> {
 
         boolean handled = false;
 
-        if (isRangeExtension(e)) {
+        if (shouldExtendRange(e)) {
             extendSelectionRange(item);
-            handled = true;
+            mHapticPerformer.run();
         } else {
-            if (!mSelectionTracker.isSelected(item.getSelectionKey())
+            if (mSelectionTracker.isSelected(item.getSelectionKey())) {
-                    && mSelectionPredicate.canSetStateForKey(item.getSelectionKey(), true)) {
+                // Long press on existing selected item initiates drag/drop.
-                // If we cannot select it, we didn't apply anchoring - therefore should not
-                // start gesture selection
-                if (selectItem(item)) {
-                    // And finally if the item was selected && we can select multiple
-                    // we kick off gesture selection.
-                    if (mSelectionPredicate.canSelectMultiple()) {
-                        mGestureStarter.run();
-                    }
-                    handled = true;
-                }
-            } else {
-                // We only initiate drag and drop on long press for touch to allow regular
-                // touch-based scrolling
                 mOnDragInitiatedListener.onDragInitiated(e);
-                handled = true;
+                mHapticPerformer.run();
+            } else if (mSelectionPredicate.canSetStateForKey(item.getSelectionKey(), true)
+                    && selectItem(item)) {
+                // And finally if the item was selected && we can select multiple
+                // we kick off gesture selection.
+                // NOTE: isRangeActive should ALWAYS be true at this point, but there have
+                // been reports indicating that assumption isn't correct. So we explicitly
+                // check isRangeActive.
+                if (mSelectionPredicate.canSelectMultiple() && mSelectionTracker.isRangeActive()) {
+                    mGestureStarter.run();
+                }
+                mHapticPerformer.run();
             }
         }
-
-        if (handled) {
-            mHapticPerformer.run();
-        }
     }
 }

app/src/main/java/androidx/recyclerview/selection/package-info.java

@@ -116,9 +116,9 @@
  * <b>Include Selection in Activity lifecycle events</b>
  *
  * <p>
- * In order to preserve state the author must the selection library in handling
+ * In order to preserve state, the author must include the selection library in the handling
- * of Activity lifecycle events. See SelectionTracker#onSaveInstanceState
+ * of Activity lifecycle events. See SelectionTracker#onSaveInstanceState and
- * and SelectionTracker#onRestoreInstanceState.
+ * SelectionTracker#onRestoreInstanceState.
  *
  * <p>A unique selection id must be supplied to
  * {@link androidx.recyclerview.selection.SelectionTracker.Builder SelectionTracker.Builder}