ProgressBar+AsyncTask 实现界面数据异步加载

ProgressBar+AsyncTask  实现界面数据异步加载



                             加载数据时



                        加载数据完成时



          加载数据异常时





2 实现说明

  加载前：界面显示异步加载控件，隐藏数据显示控件，加载异常控件

  加载成功：根据加载的数据，初始化数据显示控件

  加载失败：显示加载异常的控件，异常异步加载控件



中间的加载过程，通过AsyncTask来实现，在AsyncTask中主要实现两个方法

//后台运行，互联网后台数据加载接口

protected Integer doInBackground(String... params)



//数据加载完成，结合数据，进行UI处理

protected void onPostExecute(Integer result)



3 实现代码



  3.1界面部分


加载控件：



<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
          android:layout_width="fill_parent"
          android:layout_height="fill_parent"
          android:background="#ffffff"
          android:orientation="horizontal"
          android:gravity="center_horizontal"
          android:id="@+id/async_begin" >
         <ProgressBar        
              android:layout_width="wrap_content"       
              android:layout_height="wrap_content" 
               android:indeterminate="true"     
              style="@android:style/Widget.ProgressBar.Small.Inverse"        
              android:layout_marginRight="5dp" />
          <TextView android:text="加载信息中。。。。。"
            android:id="@+id/textView1"
            android:layout_width="wrap_content"
            android:textColor="#000000"
            android:layout_height="wrap_content"></TextView>
</LinearLayout>

复制代码

加载失败控件：



<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
          android:layout_width="fill_parent"
          android:layout_height="fill_parent"
          android:background="#ffffff"
          android:orientation="horizontal"
          android:id="@+id/async_error"
          android:visibility="gone" >
          <TextView android:text="网络异常,不能加载数据"
            android:id="@+id/textView1"
            android:layout_width="wrap_content"
            android:textColor="#000000"
            android:layout_height="wrap_content"></TextView>
          <Button android:text=""
              android:id="@+id/but_reflesh"
              android:background="@drawable/but_reflesh"
              android:layout_width="wrap_content"
               android:layout_height="wrap_content"></Button>
</LinearLayout>



数据展示控件：

View Code

<LinearLayout
     android:layout_height="wrap_content"
    android:layout_width="fill_parent"
    android:visibility="gone"
    android:id="@+id/rl_content"
    android:orientation ="vertical"
   android:gravity="center_horizontal"
    > 
   <LinearLayout android:layout_height="wrap_content" android:id="@+id/linearLayout2" android:layout_width="300px">
       <ImageView android:src="@drawable/ranklist_myrank" android:id="@+id/imageView2" android:layout_height="wrap_content" android:layout_width="wrap_content"></ImageView>
   </LinearLayout>
  
   <RelativeLayout  android:background="@drawable/ranklist_itembg"  android:layout_height="wrap_content" android:id="@+id/relativeLayout1" android:layout_width="300px">
       <LinearLayout  android:gravity="center" android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/line_photo" android:background="@drawable/ranklist_photobg" >
           <ImageView android:src="@drawable/ranklist_male" android:id="@+id/ranklist_male" android:layout_height="wrap_content" android:layout_width="wrap_content"></ImageView>
       </LinearLayout>
       <LinearLayout android:orientation="vertical" android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/linearLayout4" android:layout_toRightOf="@id/line_photo" >
               <TextView  android:textColor="#000000" android:text="1. xuwenbing" android:id="@+id/txt_nicename" android:layout_width="wrap_content" android:layout_height="wrap_content"></TextView>
               <TextView  android:textColor="#000000" android:text="积分为:1234" android:id="@+id/txt_integral" android:layout_width="wrap_content" android:layout_height="wrap_content"></TextView>
       </LinearLayout>
      
       <LinearLayout  android:gravity="center_vertical" android:orientation="vertical" android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/linearLayout4"   android:layout_alignParentRight="true" >
           <ImageView android:src="@drawable/ranklist_goto" android:id="@+id/imageView3" android:layout_height="wrap_content" android:layout_width="wrap_content"></ImageView>
          </LinearLayout>
   </RelativeLayout>
  
   <LinearLayout android:layout_height="wrap_content" android:id="@+id/linearLayout3" android:layout_width="wrap_content">
       <ImageView android:src="@drawable/ranklist_rank_other" android:id="@+id/imageView4" android:layout_height="wrap_content" android:layout_width="wrap_content"></ImageView>
  
   </LinearLayout>
   <LinearLayout android:layout_height="wrap_content" android:id="@+id/linearLayout5" android:layout_width="300px">
       <ListView   android:background="@drawable/ranklist_itembg"  android:scrollbars="vertical" android:layout_height="300px" android:id="@+id/listView_ranklist" android:layout_width="wrap_content"></ListView>
   </LinearLayout>
  </LinearLayout> 



3.2后台代码

AsyncTask 类的生成，和调用：

View Code

//AsyncTask
    class AsyncLoader_GuessInfo extends AsyncTask<String, Void, Integer>{
      @Override
      protected Integer doInBackground(String... params) {
         int result=0;
          try{
              //加载数据
              if(params[0].length()>0)
                  model= IntegralDataServiceHelper.GetRank(params[0],ProjectConstant.AppID);
              list= IntegralDataServiceHelper.GetTopList(0, 10,ProjectConstant.AppID);
              if(list!=null)
                  result=2;
          }
         catch(Exception ex){
             result=-1;
         }     
        return result;
      }
     
      @Override  //处理界面
      protected void onPostExecute(Integer result) { 
          Log.i("ExerciseGuess", "onPostExecute(Result result) called"); 
       
          if( result==2)
                  LoadAndBandingData();
           else
           {
            LinearLayout async_begin=(LinearLayout)findViewById(R.id.async_begin);
               async_begin.setVisibility(View.GONE);
              
               LinearLayout async_error=(LinearLayout)findViewById(R.id.async_error);
            async_error.setVisibility(View.VISIBLE);
             
           }
       } 
    }



调用：new AsyncLoader_GuessInfo().execute(account);


异步界面，重试部分实现



//加载刷新按钮事件   
        Button but_reflesh=(Button)findViewById(R.id.but_reflesh);
        but_reflesh.setOnClickListener(new  Button.OnClickListener()
        {
            public void onClick(View v){
                //显示加载的部分
                LinearLayout async_begin=(LinearLayout)findViewById(R.id.async_begin);
                   async_begin.setVisibility(View.VISIBLE);
                  
                //隐藏异步加载失败部分
                      LinearLayout async_error=(LinearLayout)findViewById(R.id.async_error);
                async_error.setVisibility(View.GONE);
                //异步加载
                new AsyncLoader_GuessInfo().execute(account);
               
            }
        });


界面初始化数据部分：
View Code

public void LoadAndBandingData()
    {
        LinearLayout async_begin=(LinearLayout)findViewById(R.id.async_begin);
        async_begin.setVisibility(View.GONE);
        LinearLayout rl_content=(LinearLayout)findViewById(R.id.rl_content);
        rl_content.setVisibility(View.VISIBLE);
       
       
        TextView txt_nicename =(TextView)findViewById(R.id.txt_nicename);
         TextView txt_integral =(TextView)findViewById(R.id.txt_integral); 
           
          if(model!=null)
          {
              txt_nicename.setText(String.valueOf(model.RankNo)+". "+model.UserNiceName);
              txt_integral.setText("当前的积分："+String.valueOf(model.IntegralSum));
          }
          else
          {
              txt_nicename.setText("当前还没有注册用户！");
              txt_integral.setText("当前的积分：0"); 
          }
         
          ListView listview =(ListView)findViewById(R.id.listView_ranklist);
          listview.setAdapter(new RankListAdapter(this, R.layout.sub_ranlist_item,list));
        //增加选择事件
          listview.setOnItemClickListener(new AdapterView.OnItemClickListener() {

               @Override
               public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,
                       long arg3) {
               }   
          });


转自： http://www.cnblogs.com/macroxu-1982/archive/2011/08/11/2135233.html