修改后的代码
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import java.io.InputStream;
import java.lang.ref.WeakReference;
import java.net.HttpURLConnection;
import java.net.URL;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.AsyncTask;
import android.util.Log;
import android.widget.ImageView;
/** * @类名:ImageDownloader
* @功能描述:优化的ImageDownloader, 不带缓存,在线下载,用户头像请使用。
* @作者: William Xu
* @创建日期:2013-6-7
* @修改人:
* @修改日期:
* @修改备注:
* @版本号:1.0
*/
public class ImageDownloader {
public void download(String url, ImageView imageView) {
BitmapDownloaderTask task = new BitmapDownloaderTask(imageView);
task.execute(url);
}
class BitmapDownloaderTask extends AsyncTask<String, Void, Bitmap> {
private final WeakReference<ImageView> imageViewReference; // 使用WeakReference解决内存问题
public BitmapDownloaderTask(ImageView imageView) {
imageViewReference = new WeakReference<ImageView>(imageView);
}
@Override
protected Bitmap doInString... params) { // 实际的下载线程,内部其实是concurrent线程,所以不会阻塞
Bitmap bitmap = null ;
try {
URL imageUrl = new URL(params[ 0 ]);
HttpURLConnection conn = (HttpURLConnection) imageUrl
.openConnection();
conn.setConnectTimeout( 30000 );
conn.setReadTimeout( 30000 );
conn.setInstanceFollowRedirects( true );
InputStream is = conn.getInputStream();
bitmap = BitmapFactory.decodeStream(is);
} catch (Exception ex) {
Log.e( "" ,
"getBitmap catch Exception...
message = "
+ ex.getMessage());
}
return bitmap;
}
@Override
protected void onPostExecute(Bitmap bitmap) { // 下载完后执行的
if (isCancelled()) {
bitmap = null ;
}
if (imageViewReference != null ) {
ImageView imageView = imageViewReference.get();
if (imageView != null && bitmap != null ) {
imageView.setImageBitmap(bitmap); // 下载完设置imageview为刚才下载的bitmap对象
}
}
}
}
} |
本文转自william_xu 51CTO博客,原文链接:http://blog.51cto.com/williamx/1218518,如需转载请自行联系原作者