Android 异步任务加载图片代码

自己写的Android 异步任务加载图片代码

 

public class DownloadImageTask extends AsyncTask<String, Void, Bitmap>
{
	private static final String TAG = "DownloadImageTask";
	private String url;
	private ImageView imageViewReference;

	public DownloadImageTask(ImageView imageView)
	{
		imageViewReference = imageView;
	}

	@Override
	protected Bitmap doInBackground(String... params)
	{
		// TODO Auto-generated method stub
		Log.d(TAG, "thumb_image_url:" + params[0]);
		url = params[0];
		return downloadBitmap(url);
	}

	@Override
	protected void onPostExecute(Bitmap bitmap)
	{
		// BitmapDrawable drawable=BitmapDrawable.
		// TODO Auto-generated method stub
		if (imageViewReference != null)
		{
			imageViewReference.setImageBitmap(bitmap);
		}
	}

	Bitmap downloadBitmap(String url)
	{
		final int IO_BUFFER_SIZE = 4 * 1024;
		final HttpClient client = new DefaultHttpClient();
		// : AndroidHttpClient.newInstance("Android");
		final HttpGet getRequest = new HttpGet(url);
		try
		{
			HttpResponse response = client.execute(getRequest);
			final int statusCode = response.getStatusLine().getStatusCode();
			if (statusCode != HttpStatus.SC_OK)
			{
				Log.v("ImageDownloader", "Error" + statusCode + "while restrieving bitmap from" + url);
				return null;
			}
			final HttpEntity entity = response.getEntity();
			if (entity != null)
			{

				InputStream inputStream = null;
				try
				{
					inputStream = entity.getContent();
					return BitmapFactory.decodeStream(inputStream);
				} finally
				{
					if (inputStream != null)
					{
						inputStream.close();
					}
					entity.consumeContent();
				}
			}
		} catch (IOException e)
		{
			getRequest.abort();
			Log.v(TAG, "I/O error while retrieving bitmap from " + url, e);
		} catch (IllegalStateException e)
		{
			getRequest.abort();
			Log.w(TAG, "Incorrect URL: " + url);
		} catch (Exception e)
		{
			getRequest.abort();
			Log.w(TAG, "Error while retrieving bitmap from " + url, e);
		} finally
		{
			if ((client instanceof AndroidHttpClient))
			{
				((AndroidHttpClient) client).close();
			}
		}
		return null;
	}
}