public class main extends Activity {
	ImageView imageView01;
	TextView textView;
	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);

		textView = (TextView) this.findViewById(R.id.TextView01);
		imageView01 = (ImageView) this.findViewById(R.id.ImageView01);
		GetImage getImage = new GetImage();
		getImage.execute("http://hi.csdn.net/attachment/201010/27/0_1288149117Yk8W.gif");
	}

	private class GetImage extends AsyncTask {

		public GetImage() {
			super();
			// TODO Auto-generated constructor stub
		}

		@Override
		protected void onCancelled() {
			Log.i("czb", "onCancelled is running...");

			super.onCancelled();
		}

		@Override
		protected void onPostExecute(Object result) {
			/*
			 * 此方法在主线程执行，任务执行的结果作为此方法的参数返回
			 */
			Log.i("czb", "onPostExecute is running...");
			Log.i("czb", "result == null ? " + (result == null));
			imageView01.setImageBitmap((Bitmap)result);
			
			super.onPostExecute(result);
		}

		@Override
		protected void onPreExecute() {
			/*
			 * 执行预处理，它运行于UI线程，可以为后台任务做一些准备工作，比如绘制一个进度条控件
			 */
			Log.i("czb", "onPreExecute is running...");
			
			super.onPreExecute();
		}

		@Override
		protected void onProgressUpdate(Object... values) {
			/*
			 * 此方法在主线程执行，用于显示任务执行的进度。
			 */
			Log.i("czb", "onProgressUpdate is running...");
			// 由publishProgress传递的值
			Log.i("czb", "values " + values[0]);
			super.onProgressUpdate(values);
		}

		@Override
		protected Object doInBackground(Object... params) {
			/*
			 * 此方法在后台线程执行，完成任务的主要工作，通常需要较长的时间。
			 * 在执行过程中可以调用publicProgress(Progress…)来更新任务的进度。
			 */
			Log.i("czb", "doInBackground is running...");
			
			try {
				Bitmap bitmap;
				HttpClient client = new DefaultHttpClient();
				// params[0]代表连接的url
				URI uri = URI.create((String) params[0]);
				HttpGet get = new HttpGet(uri);
				HttpResponse response = client.execute(get);
				HttpEntity entity = response.getEntity();
				long length = entity.getContentLength();
				Log.i("czb", "  " + length);
				InputStream in = entity.getContent();
				if (in != null) {
					ByteArrayOutputStream baos = new ByteArrayOutputStream();
					/*byte[] buf = new byte[128];
					int ch = -1;
					int count = 0;
					while ((ch = in.read(buf)) != -1) {
						baos.write(buf, 0, ch);
						count += ch;
						if (length > 0) {
							// 如果知道响应的长度，调用publishProgress（）更新进度
							// onProgressUpdate读取进度
							publishProgress((int) ((count / (float) length) * 100));
						}
						// 为了在模拟器中清楚地看到进度，让线程休眠100ms
						//Thread.sleep(100);
					}*/
					bitmap = BitmapFactory.decodeStream(in);
					in.close();
					baos.close();
					return bitmap;
				}
			} catch (Exception e) {
				e.printStackTrace();
			}
			return null;
		}

	}
}