AsyncListView.java

/*
 * Copyright (C) 2012 Lucas Rocha
 *
 * 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.lucasr.smoothie;

import android.content.Context;
import android.util.AttributeSet;
import android.widget.ListAdapter;
import android.widget.ListView;

/**
 * <p>A {@link android.widget.ListView ListView} that can asynchronously load the
 * content of its items through an {@link ItemManager}.</p>
 *
 * <p>AsyncListView behaves exactly like an ordinary
 * {@link android.widget.ListView ListView} when it has no {@link ItemManager}
 * set. Once an {@link ItemManager} is set, it will you use the associated
 * {@link ItemLoader} to asynchronously load the content of its items in a
 * background thread as the the user scrolls the view.</p>
 *
 * <p>Use {@link #setItemManager(ItemManager)} to set an {@link ItemManager} on
 * the view. An example call:</p>
 *
 * <pre>
 * ItemManager.Builder builder = new ItemManager.Builder(new YourItemLoader());
 * builder.setPreloadItemsEnabled(true).setPreloadItemsCount(10);
 * ItemManager itemManager = builder.build();
 *
 * AsyncListView listView = (AsyncListView) findViewById(R.id.list);
 * listView.setItemManager(itemManager);
 * </pre>
 *
 * @author Lucas Rocha <lucasr@lucasr.org>
 */
public class AsyncListView extends ListView implements AsyncAbsListView {
    private final ItemManaged mItemManaged;

    @SuppressWarnings("javadoc")
    public AsyncListView(Context context, AttributeSet attrs) {
        super(context, attrs);
        mItemManaged = new ItemManaged(this);
    }

    /**
     * Sets an {@link ItemManager} on the {@link AsyncListView}. Once this is
     * set, the {@link AsyncListView} will use its associated {@link ItemLoader}
     * to asynchronously load the content its items in a background thread.
     *
     * @param itemManager - {@link ItemManager} to associate with the view.
     */
    @Override
    public void setItemManager(ItemManager itemManager) {
        mItemManaged.setItemManager(itemManager);
    }

    @Override
    public void setOnScrollListener(OnScrollListener l) {
        mItemManaged.setOnScrollListener(l);
        if (!mItemManaged.hasItemManager()) {
            super.setOnScrollListener(l);
        }
    }

    @Override
    public void setOnTouchListener(OnTouchListener l) {
        mItemManaged.setOnTouchListener(l);
        if (!mItemManaged.hasItemManager()) {
            super.setOnTouchListener(l);
        }
    }

    @Override
    public void setOnItemSelectedListener(OnItemSelectedListener l) {
        mItemManaged.setOnItemSelectedListener(l);
        if (!mItemManaged.hasItemManager()) {
            super.setOnItemSelectedListener(l);
        }
    }

    @Override
    public ListAdapter getAdapter() {
        if (mItemManaged != null) {
            return mItemManaged.getWrappedAdapter();
        } else {
            return super.getAdapter();
        }
    }

    @Override
    public void setAdapter(ListAdapter adapter) {
        super.setAdapter(mItemManaged.wrapAdapter(adapter));
    }
}