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/*
* Copyright (C) 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 android.arch.paging;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.annotation.RestrictTo;
import android.support.v7.recyclerview.extensions.DiffCallback;
import android.support.v7.util.DiffUtil;
import android.support.v7.util.ListUpdateCallback;
/** @hide */
@RestrictTo(RestrictTo.Scope.LIBRARY_GROUP)
class SparseDiffHelper {
private SparseDiffHelper() {
}
@NonNull
static <T> DiffUtil.DiffResult computeDiff(
final PageArrayList<T> oldList, final PageArrayList<T> newList,
final DiffCallback<T> diffCallback, boolean detectMoves) {
if (!oldList.isImmutable()) {
throw new IllegalArgumentException("list must be immutable to safely perform diff");
}
if (!newList.isImmutable()) {
throw new IllegalArgumentException("list must be immutable to safely perform diff");
}
return DiffUtil.calculateDiff(new DiffUtil.Callback() {
@Nullable
@Override
public Object getChangePayload(int oldItemPosition, int newItemPosition) {
T oldItem = oldList.get(oldItemPosition);
T newItem = newList.get(newItemPosition);
if (oldItem == null || newItem == null) {
return null;
}
return diffCallback.getChangePayload(oldItem, newItem);
}
@Override
public int getOldListSize() {
return oldList.size();
}
@Override
public int getNewListSize() {
return newList.size();
}
@Override
public boolean areItemsTheSame(int oldItemPosition, int newItemPosition) {
T oldItem = oldList.get(oldItemPosition);
T newItem = newList.get(newItemPosition);
if (oldItem == newItem) {
return true;
}
if (oldItem == null || newItem == null) {
return false;
}
return diffCallback.areItemsTheSame(oldItem, newItem);
}
@Override
public boolean areContentsTheSame(int oldItemPosition, int newItemPosition) {
T oldItem = oldList.get(oldItemPosition);
T newItem = newList.get(newItemPosition);
if (oldItem == newItem) {
return true;
}
if (oldItem == null || newItem == null) {
return false;
}
return diffCallback.areContentsTheSame(oldItem, newItem);
}
}, detectMoves);
}
static <T> void dispatchDiff(ListUpdateCallback callback,
final DiffUtil.DiffResult diffResult) {
// Simple case, dispatch & return
diffResult.dispatchUpdatesTo(callback);
}
}
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