[转]Android ListView异步加载图片

本文转自：http://www.cnblogs.com/stay/articles/1900012.html

package cn.riddles.activity;
  
import android.app.Activity;
import android.os.Bundle;
import android.widget.ListView;
  
public class MainActivity extends Activity {
    private ListView lv;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        lv = (ListView) this.findViewById(R.id.test_lv);
        lv.setAdapter(new SongListAdapter(this));
    }
}

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package cn.riddles.activity;
  
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;
/**
 * @author riddlezhang 歌曲条目适配器
 */
public class SongListAdapter extends BaseAdapter {
    private static final String TAG = "SongListAdapter";
    private Context mContext;
    private String[] strings = {"王力宏","吴尊","何润东","金城武","吴彦祖"};
    private String[] paths = {"http://list.image.baidu.com/t/image_category/galleryimg/menstar/hk/wang_li_hong.jpg",
            "http://list.image.baidu.com/t/image_category/galleryimg/menstar/hk/wu_zun.jpg",
            "http://list.image.baidu.com/t/image_category/galleryimg/menstar/hk/he_run_dong.jpg",
            "http://list.image.baidu.com/t/image_category/galleryimg/menstar/hk/jin_cheng_wu.jpg",
            "http://list.image.baidu.com/t/image_category/galleryimg/menstar/hk/wu_yan_zu.jpg"};
    public SongListAdapter(Context mContext) {
        this.mContext = mContext;
    }
  
    public void setmContext(Context mContext) {
        this.mContext = mContext;
    }
  
    public int getCount() {
        return paths.length;
    }
  
    public Object getItem(int position) {
        return position;
    }
  
    public long getItemId(int position) {
        return position;
    }
  
    public View getView(int position, View convertView, ViewGroup parent) {
        convertView = LayoutInflater.from(mContext).inflate(R.layout.lv_adapter, null);
        ImageView image = (ImageView) convertView.findViewById(R.id.image);
        TextView songer = (TextView) convertView.findViewById(R.id.songer);
        image.setTag(paths[position]);
        songer.setText(strings[position]);
        new CanvasImageTask().execute(image);//异步加载图片
        Log.i(TAG, "execute:"+strings[position]);
        return convertView;
    }
      
}
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<DIV class=cnblogs_Highlighter><PRE class=brush:java;gutter:false;>package cn.riddles.activity;
  
import java.io.InputStream;
import java.lang.ref.SoftReference;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.HashMap;
  
import android.content.Context;
import android.graphics.drawable.Drawable;
import android.os.AsyncTask;
import android.util.Log;
import android.view.View;
import android.webkit.URLUtil;
  
/**
 * @author riddlezhang 异步加载图片
 */
public class AsyncViewTask extends AsyncTask<View, Void, Drawable> {
    private View mView;
    private HashMap<String, SoftReference<Drawable>> imageCache;
  
    public AsyncViewTask(Context mContext, String mobileinfo) {
        imageCache = new HashMap<String, SoftReference<Drawable>>();
    }
  
    protected Drawable doInBackground(View... views) {
        Drawable drawable = null;
        View view = views[0];
        if (view.getTag() != null) {
            if (imageCache.containsKey(view.getTag())) {
                SoftReference<Drawable> cache = imageCache.get(view.getTag().toString());
                drawable = cache.get();
                if (drawable != null) {
                    return drawable;
                }
            }
            try {
                if (URLUtil.isHttpUrl(view.getTag().toString())) {// 如果为网络地址。则连接url下载图片
                    URL url = new URL(view.getTag().toString());
                    HttpURLConnection conn = (HttpURLConnection) url.openConnection();
                    conn.setDoInput(true);
                    conn.connect();
                    InputStream stream = conn.getInputStream();
                    drawable = Drawable.createFromStream(stream, "src");
                    stream.close();
                } else {// 如果为本地数据，直接解析
                    drawable = Drawable.createFromPath(view.getTag().toString());
                }
            } catch (Exception e) {
                Log.v("img", e.getMessage());
                return null;
            }
        }
        this.mView = view;
        return drawable;
    }
  
    protected void onPostExecute(Drawable drawable) {
        if (drawable != null) {
            this.mView.setBackgroundDrawable(drawable);
            this.mView = null;
        }
    }
  
}
</PRE>
</DIV>

 

posted on 2012-06-11 14:54  freeliver54  阅读(323)  评论(0)    收藏  举报

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