無法調用AsyncTask doInBackground（）和onPostExecute

Question

Strangley，我的AsyncTask將執行onPreExecute而不是doInBackground()或onPostExecute()。 Logcat沒有錯誤或消息表明出現問題。

class LocationTask extends AsyncTask<String, Void, String>{ 

    @Override 
    protected void onPreExecute() { 
     super.onPreExecute(); 
     Log.d(TAG, "onPreExecute============"); 
    } 

    @Override 
    protected String doInBackground(String... urls) { 
     Log.d(TAG, "doInBackground============"); 
     Log.d(TAG, "urls[0]:" + urls[0]); 
     return "test"; 
    } 

    @Override 
    protected void onPostExecute(String result){ 
     // TODO Auto-generated method stub 
     super.onPostExecute(result); 
     Log.d(TAG, "onPostExecute============"); 
    } 
} 

public class CsLocationTaskTest extends AndroidTestCase { 

    public void testExecute(){ 
     LocationTask task = new LocationTask(); 
     task.execute("my_test_url", null); 
    } 
} 

你看，是AsycTask沒什麼特別的，但和doInBackground被onPostExecute沒有被調用兩種測試情況，在我Activity。我不明白髮生了什麼，請讓我明白什麼是錯的。謝謝。

Answer 1

AsyncTask需要是CsLocationTaskTest的子類別。此外，你不需要null。

每開發文檔：

"AsyncTask must be subclassed to be used. The subclass will override at least one method (doInBackground(Params...)), and most often will override a second one (onPostExecute(Result).)"

找到在：http://developer.android.com/reference/android/os/AsyncTask.html

試試這個：

public class CsLocationTaskTest extends AndroidTestCase { 

    public void testExecute(){ 
     LocationTask task = new LocationTask(); 
     task.execute("my_test_url"); 
    } 

    class LocationTask extends AsyncTask<String, Void, String>{ 

    @Override 
    protected void onPreExecute() { 
     super.onPreExecute(); 
     Log.d(TAG, "onPreExecute============"); 
    } 

    @Override 
    protected String doInBackground(String... urls) { 
     Log.d(TAG, "doInBackground============"); 
     Log.d(TAG, "urls[0]:" + urls[0]); 
     return "test"; 
    } 

    @Override 
    protected void onPostExecute(String result){ 
     // TODO Auto-generated method stub 
     super.onPostExecute(result); 
     Log.d(TAG, "onPostExecute============"); 
    } 
} 


}