Question

我是机器人中的新手并说“穷人”英语。

我有一个片段，我必须在执行webview之前测试如果网址存在。

在我的第一次测试中，我得到了一个“ android.os.NetworkOnMainThreadException ”

所以，我使用 AsyncTask

如果url存在，如何测试我的片段活动？

我在Android Studio下测试并在调试'doInBackground'中没有执行???

提前，非常感谢您的支持

这是我的班级AsyncTask：

public class ExistUrl extends AsyncTask<String, Void, Boolean> {

   private static final String TAG = "CheckURL";
   String filename="";

   public ExistUrl(String URL) {
    this.filename=URL;
    Log.d(TAG, "url="+ this.filename);
  }

 @Override
    protected Boolean doInBackground(String... params) {
      //  validateParams(params);
        Log.v("name of file",this.filename);
        Boolean OK =MyUtilities.exists(params[0]);
        Log.v("***********  retour     exists class:", Boolean.toString(OK));

    return OK;
    }

   @Override
   protected void onCancelled() {
    super.onCancelled();
    Log.i(TAG, "Background cancelled.");
   }

   @Override
   protected void onPostExecute(Boolean result){
    super.onPostExecute(result);
       String message = null;
       if (result)
           message = "Url  succeeded.";
       else
           message = "Url failed.";
       Log.i(TAG, message);                               }
   }}

这是Myutilities.exists

    public static boolean exists(String URLName){

    try {
        HttpURLConnection.setFollowRedirects(false);
        // note : you may also need
        //        HttpURLConnection.setInstanceFollowRedirects(false)
        HttpURLConnection con =
                (HttpURLConnection) new URL(URLName).openConnection();
        con.setRequestMethod("HEAD");
        return (con.getResponseCode() == HttpURLConnection.HTTP_OK);
    }
    catch (Exception e) {
        e.printStackTrace();
        return false;
    }
  }

我的片段活动

    public class HainautFragment extends Fragment {

    public HainautFragment(){}

   @Override
   public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState) {
                           View rootView = inflater.inflate(R.layout.fragment_hainaut, container, false);
    String Zone = "http://www.tournoi.org/tournoilive/affiche_categorie_dbf.asp?nuclb=1005&datedeb=2013/9/13&datefin=2013/9/22&IdTournoi=309569";

                        ConnectionDetector cd = new ConnectionDetector(getActivity());
                        Boolean isInternetPresent = cd.isConnectingToInternet();
                        if (isInternetPresent) {

                                new ExistUrl(Zone).execute();

        *********************//how to test return***************************

                                                       }
    return rootView;
}

Answer 1

在这里传递网址

new ExistUrl(Zone).execute(url);

Answer 2

试试这个..

if (isInternetPresent) {

     if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB)
          new ExistUrl(Zone).executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR, new String[]{null});
     else
          new ExistUrl(Zone).execute(new String[]{null});

}

然后，一旦您将url分配给文件名字符串，如this.filename=URL;，则无需再次使用this.filename，只需使用filename

public ExistUrl(String URL) {
    this.filename=URL;
    Log.d(TAG, "url="+ filename);
}

修改

您的发送Boolean OK =MyUtilities.exists(params[0]);就像这样发送 MyUtilities.exists(filename);

@Override protected Boolean doInBackground(String... params) { Log.v("name of file",filename); //Correction here Boolean OK =MyUtilities.exists(filename); //Correction here Log.v("*********** retour exists class:", Boolean.toString(OK)); return OK; }

测试片段中是否存在URL

2 个答案: