总结Android中多线程更新应用的页面信息的方式

获取网络图片的示例代码：

 public class MainActivity extends ActionBarActivity {
  private ImageView iv;
  private Button bt;
  private String imagePath = "http://www.easck.com/sa";
  private ProgressDialog dialog;

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    iv = (ImageView) findViewById(R.id.imageView1);
    bt = (Button) findViewById(R.id.button1);
    dialog = new ProgressDialog(this);
    dialog.setTitle("提示信息：");
    dialog.setMessage("正在下载。。。");
    bt.setOnClickListener(new OnClickListener() {

      @Override
      public void onClick(View v) {
        new MyTask().execute(imagePath);

      }
    });
  }
  public class MyTask extends AsyncTask<String, Void, Bitmap>{

    @Override
    protected Bitmap doInBackground(String... params) {
      HttpClient httpClient = new DefaultHttpClient();
      HttpGet httpGet = new HttpGet(params[0]);
      Bitmap bitmap = null;
      try {
        HttpResponse httpResponse = httpClient.execute(httpGet);
        if (httpResponse.getStatusLine().getStatusCode()==200) {
          HttpEntity httpEntity = httpResponse.getEntity();
          byte[] data = EntityUtils.toByteArray(httpEntity);
          bitmap= BitmapFactory.decodeByteArray(data, 0, data.length);
        }
      } catch (Exception e) {

        e.printStackTrace();
      }

      return bitmap;
    }

    @Override
    protected void onPreExecute() {      
      super.onPreExecute();
      dialog.show();
    }

    @Override
    protected void onPostExecute(Bitmap result) {      
      super.onPostExecute(result);
      iv.setImageBitmap(result);
      dialog.dismiss();
    }    
   }  
  }

 

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