Sample

ProductListDiffCallback.java

package com.despotoski.nikola.diffutilexample;

import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v7.util.DiffUtil;

import java.util.List;

import static com.despotoski.nikola.diffutilexample.Product.KEY_DISCOUNT;

/**
 * Created by Nikola on 8/17/2016.
 */

public class ProductListDiffCallback extends DiffUtil.Callback {
    private List<Product> mOldList;
    private List<Product> mNewList;

    public ProductListDiffCallback(List<Product> oldList, List<Product> newList) {
        this.mOldList = oldList;
        this.mNewList = newList;
    }

    @Override
    public int getOldListSize() {
        return mOldList != null ? mOldList.size() : 0;
    }

    @Override
    public int getNewListSize() {
        return mNewList != null ? mNewList.size() : 0;
    }

    @Override
    public boolean areItemsTheSame(int oldItemPosition, int newItemPosition) {
        return mNewList.get(newItemPosition).getProductId() == mOldList.get(oldItemPosition).getProductId();
    }

    @Override
    public boolean areContentsTheSame(int oldItemPosition, int newItemPosition) {
        return mNewList.get(newItemPosition).equals(mOldList.get(oldItemPosition));
    }

    @Nullable
    @Override
    public Object getChangePayload(int oldItemPosition, int newItemPosition) {
        Product newProduct = mNewList.get(newItemPosition);
        Product oldProduct = mOldList.get(oldItemPosition);
        Bundle diffBundle = new Bundle();
        if (newProduct.hasDiscount() != oldProduct.hasDiscount()) {
            diffBundle.putBoolean(KEY_DISCOUNT, newProduct.hasDiscount());
        }
        if (newProduct.getReviews().size() != oldProduct.getReviews().size()) {
            diffBundle.putInt(Product.KEY_REVIEWS_COUNT, newProduct.getReviews().size());
        }
        if (newProduct.getPrice() != oldProduct.getPrice()) {
            diffBundle.putFloat(Product.KEY_PRICE, newProduct.getPrice());
        }
        if (diffBundle.size() == 0) return null;
        return diffBundle;
    }
}