Android(安卓)ListView异步加载图片

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));    }}

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;    }     }

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;        }    } }

转帖：http://www.cnblogs.com/stay/archive/2010/12/08/1900012.html

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