Added patched recyclerview-selection 1.0.0

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

@@ -0,0 +1,110 @@
+/*
+ * Copyright 2017 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 androidx.recyclerview.selection;
+
+import android.util.SparseArray;
+import android.view.View;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+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
+ * RecyclerView, and are removed from the cache as they are recycled.
+ *
+ * <p>
+ * There are trade-offs with this implementation as it necessarily auto-boxes {@code long}
+ * stable id values into {@code Long} values for use as selection keys. The core Selection API
+ * uses a parameterized key type to permit other keys (such as Strings or URIs).
+ */
+public final class StableIdKeyProvider extends ItemKeyProvider<Long> {
+
+    private final SparseArray<Long> mPositionToKey = new SparseArray<>();
+    private final Map<Long, Integer> mKeyToPosition = new HashMap<Long, Integer>();
+    private final RecyclerView mRecyclerView;
+
+    /**
+     * Creates a new key provider that uses cached {@code long} stable ids associated
+     * with the RecyclerView items.
+     *
+     * @param recyclerView the owner RecyclerView
+     */
+    public StableIdKeyProvider(@NonNull RecyclerView recyclerView) {
+
+        // Since this provide is based on stable ids based on whats laid out in the window
+        // we can only satisfy "window" scope key access.
+        super(SCOPE_CACHED);
+
+        mRecyclerView = recyclerView;
+
+        mRecyclerView.addOnChildAttachStateChangeListener(
+                new OnChildAttachStateChangeListener() {
+                    @Override
+                    public void onChildViewAttachedToWindow(View view) {
+                        onAttached(view);
+                    }
+
+                    @Override
+                    public void onChildViewDetachedFromWindow(View view) {
+                        onDetached(view);
+                    }
+                }
+        );
+
+    }
+
+    @SuppressWarnings("WeakerAccess") /* synthetic access */
+    void onAttached(@NonNull View view) {
+        RecyclerView.ViewHolder holder = mRecyclerView.findContainingViewHolder(view);
+        int position = holder.getAdapterPosition();
+        long id = holder.getItemId();
+        if (position != RecyclerView.NO_POSITION && id != RecyclerView.NO_ID) {
+            mPositionToKey.put(position, id);
+            mKeyToPosition.put(id, position);
+        }
+    }
+
+    @SuppressWarnings("WeakerAccess") /* synthetic access */
+    void onDetached(@NonNull View view) {
+        RecyclerView.ViewHolder holder = mRecyclerView.findContainingViewHolder(view);
+        int position = holder.getAdapterPosition();
+        long id = holder.getItemId();
+        if (position != RecyclerView.NO_POSITION && id != RecyclerView.NO_ID) {
+            mPositionToKey.delete(position);
+            mKeyToPosition.remove(id);
+        }
+    }
+
+    @Override
+    public @Nullable Long getKey(int position) {
+        return mPositionToKey.get(position, null);
+    }
+
+    @Override
+    public int getPosition(@NonNull Long key) {
+        if (mKeyToPosition.containsKey(key)) {
+            return mKeyToPosition.get(key);
+        }
+        return RecyclerView.NO_POSITION;
+    }
+}