| /* |
| * 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.widget.recyclerview.selection; |
| |
| import static android.support.v4.util.Preconditions.checkArgument; |
| |
| import android.support.annotation.IntDef; |
| import android.support.annotation.NonNull; |
| import android.support.annotation.Nullable; |
| |
| import java.lang.annotation.Retention; |
| import java.lang.annotation.RetentionPolicy; |
| |
| /** |
| * Provides selection library access to stable selection keys identifying items |
| * presented by a {@link android.support.v7.widget.RecyclerView RecyclerView} instance. |
| * |
| * @param <K> Selection key type. @see {@link StorageStrategy} for supported types. |
| */ |
| public abstract class ItemKeyProvider<K> { |
| |
| /** |
| * Provides access to all data, regardless of whether it is bound to a view or not. |
| * Key providers with this access type enjoy support for enhanced features like: |
| * SHIFT+click range selection, and band selection. |
| */ |
| public static final int SCOPE_MAPPED = 0; |
| |
| /** |
| * Provides access to cached data based for items that were recently bound in the view. |
| * Employing this provider will result in a reduced feature-set, as some |
| * features like SHIFT+click range selection and band selection are dependent |
| * on mapped access. |
| */ |
| public static final int SCOPE_CACHED = 1; |
| |
| @IntDef({ |
| SCOPE_MAPPED, |
| SCOPE_CACHED |
| }) |
| @Retention(RetentionPolicy.SOURCE) |
| public @interface Scope {} |
| |
| private final @Scope int mScope; |
| |
| /** |
| * Creates a new provider with the given scope. |
| * |
| * @param scope Scope can't be changed at runtime. |
| */ |
| protected ItemKeyProvider(@Scope int scope) { |
| checkArgument(scope == SCOPE_MAPPED || scope == SCOPE_CACHED); |
| |
| mScope = scope; |
| } |
| |
| final boolean hasAccess(@Scope int scope) { |
| return scope == mScope; |
| } |
| |
| /** |
| * @return The selection key at the given adapter position, or null. |
| */ |
| public abstract @Nullable K getKey(int position); |
| |
| /** |
| * @return the position corresponding to the selection key, or RecyclerView.NO_POSITION. |
| */ |
| public abstract int getPosition(@NonNull K key); |
| } |