NewsContentAsyncTaskLoader.java

package com.roboo.like.google.async;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.OptionalDataException;
import java.io.StreamCorruptedException;
import java.util.LinkedList;

import android.content.Context;

import com.roboo.like.google.GoogleApplication;
import com.roboo.like.google.news.utils.NewsContentUtils;
import com.roboo.like.google.utils.FileUtils;
import com.roboo.like.google.utils.MD5Utils;
import com.roboo.like.google.utils.NetWorkUtils;

public class NewsContentAsyncTaskLoader extends BaseAsyncTaskLoader<LinkedList<String>>
{
	private String mNewsUrl;
	private Context mContext;
	private LinkedList<String> mData;

	public NewsContentAsyncTaskLoader(Context context, String newsUrl)
	{
		super(context);
		mContext = context;
		mNewsUrl = newsUrl;
		System.out.println(" mNewsUrl = " + mNewsUrl);
	}

	@Override
	public void deliverResult(LinkedList<String> data)
	{
//		System.out.println("deliverResult ");
		super.deliverResult(mData);
	}

	@SuppressWarnings("unchecked")
	public LinkedList<String> loadInBackground()
	{
//		System.out.println("loadInBackground " );
		LinkedList<String> data = null;
		if (null == mData)
		{
			try
			{
				File file = new File(FileUtils.getFileCacheDir(mContext,
					FileUtils.TYPE_NEWS_CONTENT), MD5Utils.generate(mNewsUrl));
				if (!NetWorkUtils.isNetworkAvailable(mContext) && file.exists())
				{
					data = getOfflineData(file);
				}
				else
				{
					data = NewsContentUtils.getNewsDataList(mNewsUrl);
					saveNewsContentData(data);
				}
				mEndTime = System.currentTimeMillis();
				if (mEndTime - mStartTime < THREAD_LEAST_DURATION_TIME)
				{
					Thread.sleep(THREAD_LEAST_DURATION_TIME);
				}
			}
			catch (IOException e)
			{
				e.printStackTrace();
			}
			catch (ClassNotFoundException e)
			{
				e.printStackTrace();
			}
			catch (InterruptedException e)
			{
				e.printStackTrace();
			}
			mData = data;
		}
		return data;
	}

	private LinkedList<String> getOfflineData(File file) throws StreamCorruptedException,
		IOException, FileNotFoundException, OptionalDataException, ClassNotFoundException
	{
		LinkedList<String> data;
		ObjectInputStream objectInputStream = new ObjectInputStream(new FileInputStream(file));
		data = (LinkedList<String>) objectInputStream.readObject();
		objectInputStream.close();
		GoogleApplication.TEST = true;
		if (GoogleApplication.TEST)
		{
			System.out.println("从本地文件读取对象成功");
		}
		return data;
	}

	private void saveNewsContentData(LinkedList<String> data)
	{
		File dirFile = FileUtils.getFileCacheDir(mContext, FileUtils.TYPE_NEWS_CONTENT);
		File dataFile = new File(dirFile, MD5Utils.generate(mNewsUrl));
		try
		{
			ObjectOutputStream objectOutputStream = new ObjectOutputStream(new FileOutputStream(
				dataFile));
			objectOutputStream.writeObject(data);
			objectOutputStream.close();
			GoogleApplication.TEST = true;
			if (GoogleApplication.TEST)
			{
				System.out.println("新闻内容对象写入文件成功 :: 文件路径 = " + dataFile.getAbsolutePath());
			}
		}
		catch (FileNotFoundException e)
		{
			e.printStackTrace();
		}
		catch (IOException e)
		{
			e.printStackTrace();
		}
	}

}