samples/SupportLeanbackShowcase/app/src/main/java/android/support/v17/leanback/supportleanbackshowcase/cards/presenters/AbstractCardPresenter.java

/*
 * Copyright (C) 2015 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.support.v17.leanback.supportleanbackshowcase.cards.presenters;

import android.content.Context;
import android.support.v17.leanback.supportleanbackshowcase.models.Card;
import android.support.v17.leanback.widget.BaseCardView;
import android.support.v17.leanback.widget.Presenter;
import android.view.ViewGroup;

/**
 * This abstract, generic class will create and manage the
 * ViewHolder and will provide typed Presenter callbacks such that you do not have to perform casts
 * on your own.
 *
 * @param <T> View type for the card.
 */
public abstract class AbstractCardPresenter<T extends BaseCardView> extends Presenter {

    private static final String TAG = "AbstractCardPresenter";
    private final Context mContext;

    /**
     * @param context The current context.
     */
    public AbstractCardPresenter(Context context) {
        mContext = context;
    }

    public Context getContext() {
        return mContext;
    }

    @Override public final ViewHolder onCreateViewHolder(ViewGroup parent) {
        T cardView = onCreateView();
        return new ViewHolder(cardView);
    }

    @Override public final void onBindViewHolder(ViewHolder viewHolder, Object item) {
        Card card = (Card) item;
        onBindViewHolder(card, (T) viewHolder.view);
    }

    @Override public final void onUnbindViewHolder(ViewHolder viewHolder) {
        onUnbindViewHolder((T) viewHolder.view);
    }

    public void onUnbindViewHolder(T cardView) {
        // Nothing to clean up. Override if necessary.
    }

    /**
     * Invoked when a new view is created.
     *
     * @return Returns the newly created view.
     */
    protected abstract T onCreateView();

    /**
     * Implement this method to update your card's view with the data bound to it.
     *
     * @param card The model containing the data for the card.
     * @param cardView The view the card is bound to.
     * @see Presenter#onBindViewHolder(Presenter.ViewHolder, Object)
     */
    public abstract void onBindViewHolder(Card card, T cardView);

}