Android AsyncTask使用心得及错误处理-只能在主线程改变UI组件

标签：android asynctask   异常   网络   线程   

    大家肯定都会经常使用AsyncTask这个类，特别是在网络处理中，先看改正后的代码：这是正常的代码：

class sendKeyTask extends AsyncTask<String, Void, Integer>
	{

		@Override
		protected void onPostExecute(Integer resultCode) {
			// TODO Auto-generated method stub
			super.onPostExecute(resultCode);
			switch (resultCode) {
			case 6000:
				NotifyHelper.popNotifyInfo(InnerQuestionActivity.this, "用户信息异常", "");
				break;
			case 6001:
				NotifyHelper.popNotifyInfo(InnerQuestionActivity.this, "其他异常", "");
				break;
			case 6002:
				
				break;
			default:
				break;
			}
			// 隐藏输入法
			InputMethodManager imm = (InputMethodManager) getApplicationContext().getSystemService(Context.INPUT_METHOD_SERVICE);
			// 显示或者隐藏输入法
			imm.toggleSoftInput(0, InputMethodManager.HIDE_NOT_ALWAYS);
			innerQuestionEdit.setText("");
			//从新刷新
			new getQuestionDetailTack().execute(1);
			
		}

		@Override
		protected Integer doInBackground(String... data) {
			// TODO Auto-generated method stub
			int resultCode=4001;
			HttpClient client= new DefaultHttpClient();
			HttpPost post = new HttpPost("http://diandianapp.sinaapp.com/add_key.php");
			StringBuilder builder = new StringBuilder(); 
			List<NameValuePair> paramsList=new ArrayList<NameValuePair>();
			paramsList.add(new BasicNameValuePair("access_token", data[0]));
			paramsList.add(new BasicNameValuePair("user_name", data[1]));
			paramsList.add(new BasicNameValuePair("key_detail", data[2]));
			paramsList.add(new BasicNameValuePair("question_id", data[3]));
			for(int i=0;i<jpegDataList.size();i++)
			{
				paramsList.add(new BasicNameValuePair
						("img"+String.valueOf(i), jpegDataList.get(i)));
			}
			
			try {
				post.setEntity( new UrlEncodedFormEntity(paramsList,HTTP.UTF_8));
				} catch (UnsupportedEncodingException e1) {
				e1.printStackTrace();
				}
				try { 
				HttpResponse response = client.execute(post); 
				HttpEntity entity = response.getEntity();
				BufferedReader reader = new BufferedReader(new InputStreamReader(entity.getContent())); 
				for (String s = reader.readLine(); s != null; s = reader.readLine()) { 
				builder.append(s); 
				} 
				JSONObject jsonObject = new JSONObject(builder.toString());
				
				String stateCodeStr = jsonObject.getString("state_code"); 
				resultCode=Integer.parseInt(stateCodeStr);
				
				} 
				catch (ClientProtocolException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				} catch (IOException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				} catch (JSONException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
					//处理请求失败
				}
				finally
				{
					
				}
				return resultCode;
		
		}
		
	}

NotifyHelper.popNotifyInfo(InnerQuestionActivity.this, "其他异常", "");是对对话提示框的一个弹出方法封装，这是对UI界面的操作，问题应该就出在这儿了！

我们翻开google的说明看下：

protected abstract Result doInBackground (Params... params)

protected void onPostExecute (Result result)

protected void onPreExecute ()

我们必须要在doInbackground中，返回耗时操作的处理结果，再从onPostExecute中根据doInBackground返回的参数进行UI组件的操作！

doInBackground

Android AsyncTask使用心得及错误处理-只能在主线程改变UI组件

标签：android asynctask   异常   网络   线程   

原文地址：http://blog.csdn.net/tianyuan521521/article/details/45501339