CSDN客户端实现

本文主要讲解实现了一个CSDN的安卓客户端，主要知识点如下

1. java爬虫获取网页数据
2. 将java程序打包成jar包
3. Fragment+viewpager+TabPageIndicator实现Tab效果
4. gestureImageView实现放大缩小图片
5. imageLodar实现异步加载图上
6. XListView实现下拉刷新

java爬虫获取网页资源

package com.zhy.biz;  import java.util.ArrayList;  import java.util.List;  import org.jsoup.Jsoup;  import org.jsoup.nodes.Document;  import org.jsoup.nodes.Element;  import org.jsoup.select.Elements;  import com.zhy.bean.CommonException;  import com.zhy.bean.NewsItem;  import com.zhy.csdn.DataUtil;  import com.zhy.csdn.URLUtil;  /**  * 处理NewItem的业务类  * @author zhy  *   */  public class NewsItemBiz  {      /**      * 业界、移动、云计算      *       * @param htmlStr      * @return      * @throws CommonException       */      public List<NewsItem> getNewsItems( int newsType , int currentPage) throws CommonException      {          String urlStr = URLUtil.generateUrl(newsType, currentPage);          String htmlStr = DataUtil.doGet(urlStr);          List<NewsItem> newsItems = new ArrayList<NewsItem>();          NewsItem newsItem = null;          Document doc = Jsoup.parse(htmlStr);          Elements units = doc.getElementsByClass("unit");          for (int i = 0; i < units.size(); i++)          {              newsItem = new NewsItem();              newsItem.setNewsType(newsType);              Element unit_ele = units.get(i);              Element h1_ele = unit_ele.getElementsByTag("h1").get(0);              Element h1_a_ele = h1_ele.child(0);              String title = h1_a_ele.text();              String href = h1_a_ele.attr("href");              newsItem.setLink(href);              newsItem.setTitle(title);              Element h4_ele = unit_ele.getElementsByTag("h4").get(0);              Element ago_ele = h4_ele.getElementsByClass("ago").get(0);              String date = ago_ele.text();              newsItem.setDate(date);              Element dl_ele = unit_ele.getElementsByTag("dl").get(0);// dl              Element dt_ele = dl_ele.child(0);// dt              try              {// 可能没有图片                  Element img_ele = dt_ele.child(0);                  String imgLink = img_ele.child(0).attr("src");                  newsItem.setImgLink(imgLink);              } catch (IndexOutOfBoundsException e)              {              }              Element content_ele = dl_ele.child(1);// dd              String content = content_ele.text();              newsItem.setContent(content);              newsItems.add(newsItem);          }          return newsItems;      }  }  

详细实现参见链接

抓取csdn上的各类别的文章 （制作csdn app 二） - Hongyang - 博客频道 - CSDN.NET

将java项目打包成jar包

参考链接：在Eclipse中将Java项目打包为jar - 闵开慧的个人页面 - 开源中国社区

Fragment+viewpager+TabPageIndicator实现Tab效果

package com.zhy.csdndemo;  import com.viewpagerindicator.TabPageIndicator;  import android.os.Bundle;  import android.support.v4.app.FragmentActivity;  import android.support.v4.app.FragmentPagerAdapter;  import android.support.v4.view.ViewPager;  public class MainActivity extends FragmentActivity  {      private TabPageIndicator mIndicator ;      private ViewPager mViewPager ;      private FragmentPagerAdapter mAdapter ;      @Override      protected void onCreate(Bundle savedInstanceState)      {          super.onCreate(savedInstanceState);          setContentView(R.layout.activity_main);          mIndicator = (TabPageIndicator) findViewById(R.id.id_indicator);          mViewPager = (ViewPager) findViewById(R.id.id_pager);          mAdapter = new TabAdapter(getSupportFragmentManager());          mViewPager.setAdapter(mAdapter);          mIndicator.setViewPager(mViewPager, 0);      }  }  

详细实现参见链接

Android 使用Fragment，ViewPagerIndicator 制作csdn app主要框架 - Hongyang - 博客频道 - CSDN.NET

viewPager的适配器

package com.zhy.csdndemo;import android.support.v4.app.Fragment;import android.support.v4.app.FragmentManager;import android.support.v4.app.FragmentPagerAdapter;public class TabAdapter extends FragmentPagerAdapter{    public static final String[] TITLES = new String[] { "业界", "移动", "研发", "程序员杂志", "云计算" };    public TabAdapter(FragmentManager fm)    {        super(fm);    }    @Override    public Fragment getItem(int arg0)    {        MainFragment fragment = new MainFragment(arg0+1);        return fragment;    }    @Override    public CharSequence getPageTitle(int position)    {        return TITLES[position % TITLES.length];    }    @Override    public int getCount()    {        return TITLES.length;    }}

viewPager中的Fragment实现，其中用xListView实现了获取数据与刷新等功能

package com.zhy.csdndemo;import java.util.ArrayList;import java.util.List;import me.maxwin.view.IXListViewLoadMore;import me.maxwin.view.IXListViewRefreshListener;import me.maxwin.view.XListView;import android.annotation.SuppressLint;import android.os.AsyncTask;import android.os.Bundle;import android.support.v4.app.Fragment;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import com.zhy.bean.CommonException;import com.zhy.bean.NewsItem;import com.zhy.biz.NewsItemBiz;import com.zhy.csdn.Constaint;import com.zhy.csdndemo.adapter.NewsItemAdapter;@SuppressLint("ValidFragment")public class MainFragment extends Fragment implements IXListViewRefreshListener, IXListViewLoadMore{    /**     * 默认的newType     */    private int newsType = Constaint.NEWS_TYPE_YEJIE;    /**     * 当前页面     */    private int currentPage = 1;    /**     * 处理新闻的业务类     */    private NewsItemBiz mNewsItemBiz;    /**     * 扩展的ListView     */    private XListView mXListView;    /**     * 数据适配器     */    private NewsItemAdapter mAdapter;    /**     * 数据     */    private List<NewsItem> mDatas = new ArrayList<NewsItem>();    /**     * 获得newType     * @param newsType     */    public MainFragment(int newsType)    {        this.newsType = newsType;        mNewsItemBiz = new NewsItemBiz();    }    @Override    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)    {        return inflater.inflate(R.layout.tab_item_fragment_main, null);    }    @Override    public void onActivityCreated(Bundle savedInstanceState)    {        super.onActivityCreated(savedInstanceState);        mAdapter = new NewsItemAdapter(getActivity(), mDatas);        /**         * 初始化         */        mXListView = (XListView) getView().findViewById(R.id.id_xlistView);        mXListView.setAdapter(mAdapter);        mXListView.setPullRefreshEnable(this);        mXListView.setPullLoadEnable(this);        //mXListView.NotRefreshAtBegin();        /**         * 进来时直接刷新         */        mXListView.startRefresh();    }    @Override    public void onRefresh()    {        new LoadDatasTask().execute();    }    @Override    public void onLoadMore()    {        // TODO Auto-generated method stub    }    /**     * 记载数据的异步任务     * @author zhy     *     */    class LoadDatasTask extends AsyncTask<Void, Void, Void>    {        @Override        protected Void doInBackground(Void... params)        {            try            {                List<NewsItem> newsItems = mNewsItemBiz.getNewsItems(newsType, currentPage);                mDatas = newsItems;            } catch (CommonException e)            {                // TODO Auto-generated catch block                e.printStackTrace();            }            return null;        }        @Override        protected void onPostExecute(Void result)        {            mAdapter.addAll(mDatas);            mAdapter.notifyDataSetChanged();            mXListView.stopRefresh();        }    }}

xListView的adapter,其中使用了imageLoder

package com.zhy.csdndemo.adapter;import java.util.List;import android.content.Context;import android.util.Log;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.BaseAdapter;import android.widget.ImageView;import android.widget.TextView;import com.nostra13.universalimageloader.core.DisplayImageOptions;import com.nostra13.universalimageloader.core.ImageLoader;import com.nostra13.universalimageloader.core.ImageLoaderConfiguration;import com.nostra13.universalimageloader.core.display.FadeInBitmapDisplayer;import com.nostra13.universalimageloader.core.display.RoundedBitmapDisplayer;import com.zhy.bean.NewsItem;import com.zhy.csdn.DataUtil;import com.zhy.csdndemo.R;public class NewsItemAdapter extends BaseAdapter{    private LayoutInflater mInflater;    private List<NewsItem> mDatas;    /**     * 使用了github开源的ImageLoad进行了数据加载     */    private ImageLoader imageLoader = ImageLoader.getInstance();    private DisplayImageOptions options;    public NewsItemAdapter(Context context, List<NewsItem> datas)    {        this.mDatas = datas;        mInflater = LayoutInflater.from(context);        imageLoader.init(ImageLoaderConfiguration.createDefault(context));        options = new DisplayImageOptions.Builder().showStubImage(R.drawable.images)                .showImageForEmptyUri(R.drawable.images).showImageOnFail(R.drawable.images).cacheInMemory()                .cacheOnDisc().displayer(new RoundedBitmapDisplayer(20)).displayer(new FadeInBitmapDisplayer(300))                .build();    }    public void addAll(List<NewsItem> mDatas)    {        this.mDatas.addAll(mDatas);    }    @Override    public int getCount()    {        return mDatas.size();    }    @Override    public Object getItem(int position)    {        return mDatas.get(position);    }    @Override    public long getItemId(int position)    {        return position;    }    @Override    public View getView(int position, View convertView, ViewGroup parent)    {        ViewHolder holder = null;        if (convertView == null)        {            convertView = mInflater.inflate(R.layout.news_item_yidong, null);            holder = new ViewHolder();            holder.mContent = (TextView) convertView.findViewById(R.id.id_content);            holder.mTitle = (TextView) convertView.findViewById(R.id.id_title);            holder.mDate = (TextView) convertView.findViewById(R.id.id_date);            holder.mImg = (ImageView) convertView.findViewById(R.id.id_newsImg);            convertView.setTag(holder);        } else        {            holder = (ViewHolder) convertView.getTag();        }        NewsItem newsItem = mDatas.get(position);        holder.mTitle.setText(DataUtil.ToDBC(newsItem.getTitle()));        holder.mContent.setText(newsItem.getContent());        holder.mDate.setText(newsItem.getDate());        if (newsItem.getImgLink() != null)        {            holder.mImg.setVisibility(View.VISIBLE);            imageLoader.displayImage(newsItem.getImgLink(), holder.mImg, options);        } else        {            holder.mImg.setVisibility(View.GONE);        }        return convertView;    }    private final class ViewHolder    {        TextView mTitle;        TextView mContent;        ImageView mImg;        TextView mDate;    }}

参考链接：

客户端上显示csdn上的各类别下的的文章列表 （制作csdn app 三） - Hongyang - 博客频道 - CSDN.NET

效果如下