(android實戰)AsycTask實現非同步載入

1 實現效果說明:

1.1  
載入題目資訊之前,顯示正在載入

 

1.2載入題目資訊成功後,進行題目綁定

 

1.3載入不成功,轉到載入失敗

 

 

2 非同步載入實現

2.1  介面設定

   載入前介面

 

View Code

<?xml version="1.0" encoding="UTF-8"?>
<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"
>
<ProgressBar   
android:id="@+id/circleProgressBar"    
style="?android:attr/progressBarStyleLarge" mce_style="?android:attr/progressBarStyleLarge"  
 android:layout_width="wrap_content"   
android:layout_height="wrap_content"  
 android:visibility="gone"   
  android:max="100"
 android:progress="20"
/>  
<TextView android:text="載入資訊中。。。。。" 
            android:id="@+id/textView1" 
            android:layout_width="wrap_content" 
            android:textColor="#000000"
            android:layout_height="wrap_content"></TextView>
</LinearLayout>

   載入失敗介面

 

<?xml version="1.0" encoding="UTF-8"?>
<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"
>
<TextView android:text="網路異常,不能載入資料" android:id="@+id/textView1" android:layout_width="wrap_content" android:layout_height="wrap_content"></TextView>
<Button android:text="重新載入" android:id="@+id/button1" android:layout_width="wrap_content" android:layout_height="wrap_content"></Button> 

</LinearLayout>

2.2 建立自訂非同步類

 

//AsyncTask    class AsyncLoader_GuessInfo extends AsyncTask<String, Void, Integer>{      @Override      protected Integer doInBackground(String... params) {         int result=0;      try{      gi=GuessDataServiceHelper.GetGuessInfo(params[0]);      result=2;      }         catch(Exception ex){         result=-1;          }              return result;      }     }

 

 

2.3 調用非同步類,並根據反饋結果進行顯示不同的內容

View Code

 /*
     * 負責做下載題目資訊
     * */
private BegindownHandler mbegindownHandler = new BegindownHandler();

class BegindownHandler extends Handler {
        @Override
public void handleMessage(Message msg) {
             AsyncTask<String,Void, Integer>  results=   new AsyncLoader_GuessInfo().execute(GuessNo);
try{
if( results.get()==2)
                {
                  LoadAndBandingData(GuessNo);
                }
else
                  setContentView(R.layout.async_error);
             }
catch(Exception ex)
             {
                 setContentView(R.layout.async_error);

             }

        }
public void sleep(long delayMillis) {
this.removeMessages(0);
            sendMessageDelayed(obtainMessage(0), delayMillis);
        }
    };