app_Settings/src/com/android/settings/homepage/contextualcards/ContextualCardsAdapter.java

/*
 * Copyright (C) 2018 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 com.android.settings.homepage.contextualcards;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import androidx.annotation.LayoutRes;
import androidx.annotation.VisibleForTesting;
import androidx.lifecycle.LifecycleOwner;
import androidx.recyclerview.widget.DiffUtil;
import androidx.recyclerview.widget.GridLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

import com.android.settings.homepage.contextualcards.conditional.ConditionContextualCardRenderer;
import com.android.settings.homepage.contextualcards.slices.SliceContextualCardRenderer;
import com.android.settings.homepage.contextualcards.slices.SwipeDismissalDelegate;

import java.util.ArrayList;
import java.util.List;
import java.util.Map;

public class ContextualCardsAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder>
        implements ContextualCardUpdateListener, SwipeDismissalDelegate.Listener {
    static final int SPAN_COUNT = 2;

    private static final String TAG = "ContextualCardsAdapter";
    private static final int HALF_WIDTH = 1;
    private static final int FULL_WIDTH = 2;

    @VisibleForTesting
    final List<ContextualCard> mContextualCards;

    private final Context mContext;
    private final ControllerRendererPool mControllerRendererPool;
    private final LifecycleOwner mLifecycleOwner;

    private RecyclerView mRecyclerView;

    public ContextualCardsAdapter(Context context, LifecycleOwner lifecycleOwner,
            ContextualCardManager manager) {
        mContext = context;
        mContextualCards = new ArrayList<>();
        mControllerRendererPool = manager.getControllerRendererPool();
        mLifecycleOwner = lifecycleOwner;
        setHasStableIds(true);
    }

    @Override
    public long getItemId(int position) {
        return mContextualCards.get(position).hashCode();
    }

    @Override
    public int getItemViewType(int position) {
        final ContextualCard card = mContextualCards.get(position);
        return card.getViewType();
    }

    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, @LayoutRes int viewType) {
        final ContextualCardRenderer renderer = mControllerRendererPool.getRendererByViewType(
                mContext, mLifecycleOwner, viewType);
        final View view = LayoutInflater.from(parent.getContext()).inflate(viewType, parent, false);
        return renderer.createViewHolder(view, viewType);
    }

    @Override
    public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
        final ContextualCard card = mContextualCards.get(position);
        final ContextualCardRenderer renderer = mControllerRendererPool.getRendererByViewType(
                mContext, mLifecycleOwner, card.getViewType());
        renderer.bindView(holder, card);
    }

    @Override
    public int getItemCount() {
        return mContextualCards.size();
    }

    @Override
    public void onAttachedToRecyclerView(RecyclerView recyclerView) {
        super.onAttachedToRecyclerView(recyclerView);
        mRecyclerView = recyclerView;
        final RecyclerView.LayoutManager layoutManager = recyclerView.getLayoutManager();
        if (layoutManager instanceof GridLayoutManager) {
            final GridLayoutManager gridLayoutManager = (GridLayoutManager) layoutManager;
            gridLayoutManager.setSpanSizeLookup(new GridLayoutManager.SpanSizeLookup() {
                @Override
                public int getSpanSize(int position) {
                    final int viewType = mContextualCards.get(position).getViewType();
                    if (viewType == ConditionContextualCardRenderer.VIEW_TYPE_HALF_WIDTH
                            || viewType == SliceContextualCardRenderer.VIEW_TYPE_HALF_WIDTH) {
                        return HALF_WIDTH;
                    }
                    return FULL_WIDTH;
                }
            });
        }
    }

    @Override
    public void onContextualCardUpdated(Map<Integer, List<ContextualCard>> cards) {
        final List<ContextualCard> contextualCards = cards.get(ContextualCard.CardType.DEFAULT);
        final boolean previouslyEmpty = mContextualCards.isEmpty();
        final boolean nowEmpty = contextualCards == null || contextualCards.isEmpty();
        if (contextualCards == null) {
            mContextualCards.clear();
            notifyDataSetChanged();
        } else {
            final DiffUtil.DiffResult diffResult = DiffUtil.calculateDiff(
                    new ContextualCardsDiffCallback(mContextualCards, contextualCards));
            mContextualCards.clear();
            mContextualCards.addAll(contextualCards);
            diffResult.dispatchUpdatesTo(this);
        }

        if (mRecyclerView != null && previouslyEmpty && !nowEmpty) {
            // Adding items to empty list, should animate.
            mRecyclerView.scheduleLayoutAnimation();
        }
    }

    @Override
    public void onSwiped(int position) {
        final ContextualCard card = mContextualCards.get(position).mutate()
                .setIsPendingDismiss(true).build();
        mContextualCards.set(position, card);
        notifyItemChanged(position);
    }
}