MainActivity.DownloadWebpageTask不是抽象和的AsyncTask不重寫抽象方法doInBackground（字符串...）

Question

public class MainActivity extends Activity { 

    TextView tv; 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_main); 

     tv = (TextView) findViewById(R.id.data); 

     String serviceUrl = "-"; // I can not show it 
     String serviceKey = "-"; // I can not show it 
     serviceKey = URLEncoder.encode(serviceKey); 
     String strSrch = "406"; 
     String strUrl = serviceUrl + "?ServiceKey=" + serviceKey + "&strSrch=" + strSrch; 

     new DownloadWebpageTask().execute(strUrl); 
    } 

    private class DownloadWebpageTask extends AsyncTask<String, Void, String> { 

     @Override 
     protected String doInBackgroud(String... urls) { 
      try { 
       return (String)downloadUrl((String)urls[0]); 
      } catch (IOException e) { 
       return "Download Fail"; 
      } 
     } 

     protected void onPostExecute(String result) { 
      tv.append(result + "\n"); 
      tv.append("=======parsing result=========\n"); 

      try { 
       XmlPullParserFactory factory = XmlPullParserFactory.newInstance(); 
       factory.setNamespaceAware(true); 
       XmlPullParser xpp = factory.newPullParser(); 

       xpp.setInput(new StringReader(result)); 
       int eventType = xpp.getEventType(); 
       boolean bSet = false; 
       while (eventType != XmlPullParser.END_DOCUMENT) { 
        if (eventType == XmlPullParser.START_DOCUMENT) { 
         ; 
        } else if (eventType == XmlPullParser.START_TAG) { 
         String tag_name = xpp.getName(); 
         if (tag_name.equals("busRouteNm") || tag_name.equals("busRouteId")) 
          bSet = true; 
        } else if (eventType == XmlPullParser.TEXT) { 
         if (bSet) { 
          String content = xpp.getText(); 
          tv.append(content + "\n"); 
          bSet = false; 
         } 
        } else if (eventType == XmlPullParser.END_TAG) { 
         ; 
        } 
        eventType = xpp.next(); 
       } 
      } catch (Exception e) { 
       tv.setText(e.getMessage()); 
      } 
     } 

     private String downloadUrl(String myurl) throws IOException { 

      HttpURLConnection conn = null; 
      try { 
       URL url = new URL(myurl); 
       conn = (HttpURLConnection) url.openConnection(); 
       BufferedInputStream buf = new BufferedInputStream(conn.getInputStream()); 
       BufferedReader bufreader = new BufferedReader(new InputStreamReader(buf, "utf-8")); 
       String line = null; 
       String page = ""; 
       while ((line = bufreader.readLine()) != null) { 
        page += line; 
       } 
       return page; 
      } finally { 
       conn.disconnect(); 
      } 
     } 
    } 

} 

「私有類DownloadWebpageTask擴展的AsyncTask」 此行有錯誤：

Error:(44, 13) error: MainActivity.DownloadWebpageTask is not abstract and does not override abstract method doInBackground(String...) in AsyncTask

Answer 1

的方法錯字名稱。更改

protected String doInBackgroud 

到

protected String doInBackground 

Answer 2

改變這一行：

private class DownloadWebpageTask extends AsyncTask<String, Void, String> { 

到

private class DownloadWebpageTask extends AsyncTask<String, String, String> {