无法从服务器获取JSON数据

Question

无法获取来自服务器的数据 ，即使我有值textview按我的条件onCreate()当我删除此条件这个works就好了，我（我的意思是，在这种情况下，我是able to fetch JSON data从服务器）。

并且我尝试了很多事情，但对我来说仍然没有成功，总是得到"Unable to fetch data from server"因为我在AsyncTask的onPostExecute()方法onPostExecute()其用作Toast

我正在为TextView获取value ，可以肯定的是，它也可以调用AsyncTask的 execute方法，但始终无法从服务器获取数据

您是否有任何疑问 ：

1）为什么我在onCreate()使用这种条件，然后检查我的这个问题

2）为什么我在onPostExecute()设置适配器，然后检查我的这个问题

@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_video_category);       

        etTextToSave = (TextView) findViewById(R.id.textView2);

        sharedprefs = getSharedPreferences("MyPrefs", MODE_PRIVATE);
        etTextToSave.setText(sharedprefs.getString("SharedPrefsData",""));      

        actorsList = new ArrayList<VideoCategory>(); 

        if(etTextToSave.getText().toString().length()>0)
        {               
            new JSONAsyncTask().execute("http://microblogging.wingnity.com/JSONParsingTutorial/jsonActors");            
        }               
        centerLockHorizontalScrollview = (HSVActivity) findViewById(R.id.scrollView);

    }

    class JSONAsyncTask extends AsyncTask<String, Void, Boolean> {

            ProgressDialog dialog;

            @Override
            protected void onPreExecute() {
                super.onPreExecute();
                dialog = new ProgressDialog(MainActivity.this);
                dialog.setMessage("Loading, please wait");
                dialog.setTitle("Connecting server");
                dialog.show();
                dialog.setCancelable(false);
            }

            @Override
            protected Boolean doInBackground(String... urls) {
                try {

                    //------------------>>
                    HttpGet httppost = new HttpGet(urls[0]);
                    HttpClient httpclient = new DefaultHttpClient();
                    HttpResponse response = httpclient.execute(httppost);

                    // StatusLine stat = response.getStatusLine();
                    int status = response.getStatusLine().getStatusCode();

                    if (status == 200) {
                        HttpEntity entity = response.getEntity();
                        String data = EntityUtils.toString(entity);


                        JSONObject jsono = new JSONObject(data);
                        JSONArray jarray = jsono.getJSONArray("actors");

                        for (int i = 0; i < jarray.length(); i++) {
                            JSONObject object = jarray.getJSONObject(i);

                            Actors actor = new Actors();

                            actor.setName(object.getString("name"));
                            Log.d("Name:", object.getString("name"));
                            actor.setImage(object.getString("image"));
                            Log.d("Image:", object.getString("image"));

                            actorsList.add(actor);
                        }
                        return true;
                    }

                    //------------------>>

                } catch (ParseException e1) {
                    e1.printStackTrace();
                } catch (IOException e) {
                    e.printStackTrace();
                } catch (JSONException e) {
                    e.printStackTrace();
                }
                return false;
            }

            protected void onPostExecute(Boolean result) {
                dialog.cancel();                 
                if(result == false)
                    Toast.makeText(getApplicationContext(), "Unable to fetch data from server", Toast.LENGTH_LONG).show();
                if(actorsList != null) {
                    adapter = new VideoCategoryAdapter(getApplicationContext(), R.layout.adapter_video_category, actorsList);      
                    centerLockHorizontalScrollview.setAdapter(HomeActivity.this, adapter);
                }
            }
        }

Answer 1

我没有收到任何异常或吐司消息。 检查Json响应。

Answer 2

按照您发布的问题，您仍然从服务器获取数据，但仍然收到Toast的 “无法从服务器获取数据”的消息。 我在您的代码中做了小改动，请尝试一下并告知我。

  @Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setContentView(R.layout.activity_video_category);       

    etTextToSave = (TextView) findViewById(R.id.textView2);

    sharedprefs = getSharedPreferences("MyPrefs", MODE_PRIVATE);
    etTextToSave.setText(sharedprefs.getString("SharedPrefsData",""));      

    actorsList = new ArrayList<VideoCategory>(); 

    if(etTextToSave.getText().toString().length()>0)
    {               
        new JSONAsyncTask().execute("http://microblogging.wingnity.com/JSONParsingTutorial/jsonActors");            
    }               
    centerLockHorizontalScrollview = (HSVActivity) findViewById(R.id.scrollView);

}

class JSONAsyncTask extends AsyncTask<String, Void, Boolean> {

        ProgressDialog dialog;
        JSONObject jObj;


        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            dialog = new ProgressDialog(MainActivity.this);
            dialog.setMessage("Loading, please wait");
            dialog.setTitle("Connecting server");
            dialog.show();
            dialog.setCancelable(false);
        }

        @Override
        protected Boolean doInBackground(String... urls) {
            try {

                //------------------>>
                HttpGet httppost = new HttpGet(urls[0]);
                HttpClient httpclient = new DefaultHttpClient();
                HttpResponse response = httpclient.execute(httppost);

                // StatusLine stat = response.getStatusLine();
                int status = response.getStatusLine().getStatusCode();

                if (status == 200) {
                    HttpEntity entity = response.getEntity();
                    String data = EntityUtils.toString(entity);


                    jObj = new JSONObject(data);

                   if(!(jObj.equals(null)))
                   {

                    JSONArray jarray = jsono.getJSONArray("actors");
                    for (int i = 0; i < jarray.length(); i++) {
                        JSONObject object = jarray.getJSONObject(i);

                        Actors actor = new Actors();

                        actor.setName(object.getString("name"));
                        Log.d("Name:", object.getString("name"));
                        actor.setImage(object.getString("image"));
                        Log.d("Image:", object.getString("image"));

                        actorsList.add(actor);

                     }
                   }
                    return true;
                }

                //------------------>>

            } catch (ParseException e1) {
                e1.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            } catch (JSONException e) {
                e.printStackTrace();
            }
            return false;
        }

        protected void onPostExecute(Boolean result) {
            dialog.cancel();                 
            if(jObj== null)
                Toast.makeText(getApplicationContext(), "Unable to fetch data from server", Toast.LENGTH_LONG).show();
            if(actorsList != null) {
                adapter = new VideoCategoryAdapter(getApplicationContext(), R.layout.adapter_video_category, actorsList);      
                centerLockHorizontalScrollview.setAdapter(HomeActivity.this, adapter);
            }
        }
    }