/*
 * Copyright (C) 2012 Sebastian Kaspari
 *
 * 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 org.yaaic.adapter;

import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.view.View;
import android.view.ViewGroup;

/**
 * Implementation of {@link PagerAdapter} that represents each page as a {@link View}.
 *
 * @author Sebastian Kaspari <s.kaspari@gmail.com>
 */
public abstract class ViewPagerAdapter extends PagerAdapter
{
    /**
     * Get a View that displays the data at the specified position in the data set.
     *
     * @param position The position of the item within the adapter's data set of the item whose view we want.
     * @param pager    The ViewPager that this view will eventually be attached to.
     *
     * @return A View corresponding to the data at the specified position.
     */
    public abstract View getView(int position, ViewPager pager);

    /**
     * Determines whether a page View is associated with a specific key object as
     * returned by instantiateItem(ViewGroup, int).
     *
     * @param view   Page View to check for association with object
     * @param object Object to check for association with view
     *
     * @return true if view is associated with the key object object.
     */
    @Override
    public boolean isViewFromObject(View view, Object object) {
        return view == object;
    }

    /**
     * Create the page for the given position.
     *
     * @param container The containing View in which the page will be shown.
     * @param position  The page position to be instantiated.
     *
     * @return Returns an Object representing the new page. This does not need
     *         to be a View, but can be some other container of the page.
     */
    @Override
    public Object instantiateItem(ViewGroup container, int position) {
        ViewPager pager = (ViewPager) container;
        View view = getView(position, pager);

        pager.addView(view);

        return view;
    }

    /**
     * Remove a page for the given position.
     *
     * @param container The containing View from which the page will be removed.
     * @param position  The page position to be removed.
     * @param view      The same object that was returned by instantiateItem(View, int).
     */
    @Override
    public void destroyItem(ViewGroup container, int position, Object view) {
        ((ViewPager) container).removeView((View) view);
    }
}