AsyncTask onPreExecute方法用于在执行后台任务前做一些UI操作

1.实例化

TableListsTask task = new TableListsTask(ServerIP,"ALL", MenuActivity.this);
  //第三参数建立上下文关系

2.TableListsTask.java

package com.realhope.rmeal.ui;

import static com.realhope.rmeal.service.ConstantUtil.SERVER_ADDRESS;

import static com.realhope.rmeal.service.ConstantUtil.SERVER_PORT;

import android.content.Context; import android.os.AsyncTask;

import android.util.Log;

import com.realhope.rmeal.bean.TableLists;

import com.realhope.rmeal.util.MyUtil;

 /**异步任务  方法：menuactivity 获取台列表   * 2014-7-31   * @author Wucy   *   */

public class TableListsTask extends AsyncTask<String, Integer, String> {               

     //onPreExecute方法用于在执行后台任务前做一些UI操作        

   private static final String TAG = "ASYNC_TableListsTASK";  

private MyConnector mc = null;

  private final Context mContext;

  String mtable_no,mServerIP;  

  public TableListsTask(String ServerIP,String table_no,  Context context){   

  super();

    mContext = context;  

   mtable_no =table_no;    

mServerIP=ServerIP;   }      

    @Override   

      protected void onPreExecute() {    

         Log.i(TAG, "onPreExecute() called");          // MyUtil.showToast(OrderActivity.this, "数据上传...");         // textView.setText("loading...");             //button_toOrder.setText("正在查询....");      }                                                                                                                                                                  

//doInBackground方法内部执行后台任务,不可在此方法内修改UI             

   @Override  

   protected String doInBackground(String... params) {    

   Log.i(TAG, "doInBackground(Params... params) called");     

     try{

                if(mc == null){  

        mc = new MyConnector(mServerIP, SERVER_PORT);      

       }        

     String msg = "<#GET_TABLELIST#>"+ mtable_no;   

     mc.dout.writeUTF(msg); //发出获取台表请求   

     mc.dout.flush();     

     int size = mc.din.readInt();   //获取个数        

      mc.dout.writeUTF("<#READY_TO_READ_COMMENT#>");      

     mc.dout.flush();  

     for(int i=0;i<size;i++){   

     msg = mc.din.readUTF();  //读取每条信息        

    String [] sa = msg.split("\\|"); //切割字符串   

    TableLists tablelists = new TableLists(Integer.valueOf(sa[0]),Integer.valueOf(sa[1]),sa[2],Integer.valueOf(sa[3]),Integer.valueOf(sa[4]),Integer.valueOf(sa[5]));

          ((MenuActivity)mContext).lstDate_TableLists.add(tablelists);        

       }    

 mc=null;

    return  String.valueOf(1);     

          } catch (Exception e) { 

               Log.e(TAG, e.getMessage());                        }      

     return null;                                                         

    }                                                                                                                                                         //onProgressUpdate方法用于更新进度信息                                       @Override                                                                  

  protected void onProgressUpdate(Integer... progresses) {            

          Log.i(TAG, "onProgressUpdate(Progress... progresses) called");        

  }                                                                                                                                                         //onPostExecute方法用于在执行完后台任务后更新UI,根据后台下单结果重新绑定前台订单                     @Override                                                                   

protected void onPostExecute(String result) {       

         Log.i(TAG, "onPostExecute(Result result) called");     

         MyUtil.showToast(mContext, "取后台开台信息数据");   

       ((MenuActivity)mContext).updateTableLists();                                         }                                                                                                                                                      //onCancelled方法用于在取消执行中的任务时更改UI       

 @Override  

protected void onCancelled() {        

              Log.i(TAG, "onCancelled() called");     

        }

   }