高度な実装ガイド (オプション)

```java public class DefaultContentCardsViewBindingHandler implements IContentCardsViewBindingHandler { // Interface that must be implemented and provided as a public CREATOR // field that generates instances of your Parcelable class from a Parcel. public static final Parcelable.Creator CREATOR = new Parcelable.Creator() { public DefaultContentCardsViewBindingHandler createFromParcel(Parcel in) { return new DefaultContentCardsViewBindingHandler(); }

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public DefaultContentCardsViewBindingHandler[] newArray(int size) {
  return new DefaultContentCardsViewBindingHandler[size];
}   };

/**

• A cache for the views used in binding the items in the {@link android.support.v7.widget.RecyclerView}. */ private final Map<CardType, BaseContentCardView> mContentCardViewCache = new HashMap<CardType, BaseContentCardView>();

  @Override public ContentCardViewHolder onCreateViewHolder(Context context, List<? extends Card> cards, ViewGroup viewGroup, int viewType) { CardType cardType = CardType.fromValue(viewType); return getContentCardsViewFromCache(context, cardType).createViewHolder(viewGroup); }

  @Override public void onBindViewHolder(Context context, List<? extends Card> cards, ContentCardViewHolder viewHolder, int adapterPosition) { Card cardAtPosition = cards.get(adapterPosition); BaseContentCardView contentCardView = getContentCardsViewFromCache(context, cardAtPosition.getCardType()); contentCardView.bindViewHolder(viewHolder, cardAtPosition); }

  @Override public int getItemViewType(Context context, List<? extends Card> cards, int adapterPosition) { Card card = cards.get(adapterPosition); return card.getCardType().getValue(); }

  /**

• Gets a cached instance of a {@link BaseContentCardView} for view creation/binding for a given {@link CardType}. * {@link CardType} がキャッシュ内に見つからない場合、その {@link CardType} のビューバインディング実装 * が作成され、キャッシュに追加されます。 */ @VisibleForTesting BaseContentCardView getContentCardsViewFromCache(Context context, CardType cardType) { if (!mContentCardViewCache.containsKey(cardType)) { // Create the view here BaseContentCardView contentCardView; switch (cardType) { case BANNER: contentCardView = new BannerImageContentCardView(context); break; case CAPTIONED_IMAGE: contentCardView = new CaptionedImageContentCardView(context); break; case SHORT_NEWS: contentCardView = new ShortNewsContentCardView(context); break; case TEXT_ANNOUNCEMENT: contentCardView = new TextAnnouncementContentCardView(context); break; default: contentCardView = new DefaultContentCardView(context); break; } mContentCardViewCache.put(cardType, contentCardView); } return mContentCardViewCache.get(cardType); }

  // パーセル可能なインターフェイス方式 @Override public int describeContents() { return 0; }

  // Parcelable interface method @Override public void writeToParcel(Parcel dest, int flags) { // Retaining views across a transition could lead to a // リソースがリークするため、パーセルが変更されないままになります } } ```

```java IContentCardsViewBindingHandler viewBindingHandler = new DefaultContentCardsViewBindingHandler();

ContentCardsFragment fragment = getMyCustomFragment(); fragment.setContentCardsViewBindingHandler(viewBindingHandler); ```