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;
}

}
<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>