封装异步线程回调接口更新UI图片

封装工具类：

      1.耗时操作消息发送与接收封装到一个方法中。

      2.handler接收消息数据后，使用回调方法赋值。

代码如下：封装工具类

public class DownLoadContent {

	private ProgressDialog dialog;
	private static final int code = 1;
	
	public DownLoadContent(Context context){
		dialog = new ProgressDialog(context);
		dialog.setTitle("提示");
		dialog.setMessage("正在加载中");
	}
	public void download(final String path,final DownloadCallback callback){
		final Handler handler = new Handler(){
			@Override
			public void handleMessage(Message msg) {
				super.handleMessage(msg);
				// TODO Auto-generated method stub
				byte[] by = (byte[]) msg.obj;
				callback.loadContent(by);
				if(msg.what == code){
					dialog.dismiss();
				}
			}
		};
	    class myRunnable implements Runnable{

			@Override
			public void run() {
				// TODO Auto-generated method stub
				HttpClient httpClient = new DefaultHttpClient();
				HttpPost httpPost = new HttpPost(path);
				try {
					HttpResponse response = httpClient.execute(httpPost);
					if(response.getStatusLine().getStatusCode() == 200){
						byte[] result = EntityUtils.toByteArray(response.getEntity());
						Message msg = Message.obtain();
						msg.obj = result;
						msg.what = code;
						handler.sendMessage(msg);
					}
				} catch (ClientProtocolException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				} catch (IOException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}finally{
					httpClient.getConnectionManager().shutdown();
				}
			}
	    }
	    new Thread(new myRunnable()).start();
	    dialog.show();
	}
	//回调方法
	public interface DownloadCallback{
		
		public void loadContent(byte[] result);
	}
	
}

代码如下：Activity调用回调方法更新UI

public class MainActivity extends Activity {
	
	private Button button;
	private ImageView imageView;
	private final String image_path = "http://imgstatic.baidu.com/img/image/shouye/qichepaoche0822.jpg";
	
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        button = (Button)findViewById(R.id.button1);
        imageView = (ImageView)findViewById(R.id.imageView1);
        button.setOnClickListener(new OnClickListener() {
			
			@Override
			public void onClick(View v) {
				// TODO Auto-generated method stub
				DownLoadContent content = new DownLoadContent(MainActivity.this);
				content.download(image_path, new DownloadCallback() {
					
					@Override
					public void loadContent(byte[] result) {
						// TODO Auto-generated method stub
						Bitmap bitmap = BitmapFactory.decodeByteArray(result, 0, result.length);
						imageView.setImageBitmap(bitmap);
					}
				});
			}
		});
    }
}