Android 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;
		}
	}

}