Android error async task

Question

I develop an application that must retrieve information on a mysql database, When I execute my aplication this works but it blocks when displaying a listview.

Here is my code

public class search_ville extends Activity {
    static String purl;
    public static ArrayList < etablissement > Lesetab = new ArrayList < > ();
    private ListView lvH;
    public static etablissement etabSELECT;
    private ProgressDialog progressDialog;

    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.search_ville);
        lvH = (ListView) findViewById(R.id.listViewH);
        chargerJeuDessaie();
        rafraichirListView();

        lvH.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView < ? > parent, View view, int position, long hid) {
                afficherDesc(parent, view, position, hid);
            }
        });
    }

    public void afficherDesc(AdapterView < ? > parent, View view, int position, long hid) {
        search_ville.etabSELECT = (etablissement) parent.getItemAtPosition(position);
        Intent intent = new Intent(getApplicationContext(), DetailEtab.class);
        startActivity(intent);
    }

    private void chargerJeuDessaie() {
        progressDialog = progressDialog.show(this, "Gestion des etabs", "Telechargement en cours");
        MonAsyncTaskHttp monAsyncTaskHttp = new MonAsyncTaskHttp() {

            @Override
            protected void onPostExecute(Object o) {
                super.onPostExecute(o);
                search_ville.Lesetab.clear();
                try {
                    JSONArray jsonArray = new JSONArray(o.toString());
                    for (int i = 0; i < jsonArray.length(); i++) {
                        JSONObject jsonObject = jsonArray.getJSONObject(i);
                        etablissement etab = etablissement.factoryEtab(jsonObject);
                        search_ville.Lesetab.add(etab);

                        rafraichirListView();

                    }
                } catch (JSONException e) {
                    e.printStackTrace();
                }
                progressDialog.dismiss();
            }
        };
        monAsyncTaskHttp.execute("requete=getLesetablissement");
    }
    public void rafraichirListView() {
        ArrayAdapter < etablissement > etablissementsadapter = new ArrayAdapter < etablissement > (search_ville.this, android.R.layout.simple_list_item_1, Lesetab);
        lvH.setAdapter(etablissementsadapter);
    }
}

Error log :

04-22 16:45:48.815 21234-21234/ddec.applicationddec E/AndroidRuntime: FATAL EXCEPTION: main
      java.lang.NullPointerException
          at ddec.applicationddec.search_ville$2.onPostExecute(search_ville.java:68)
          at android.os.AsyncTask.finish(AsyncTask.java:631)
          at android.os.AsyncTask.access$600(AsyncTask.java:177)
          at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:644)
          at android.os.Handler.dispatchMessage(Handler.java:99)
          at android.os.Looper.loop(Looper.java:176)
          at android.app.ActivityThread.main(ActivityThread.java:5419)
          at java.lang.reflect.Method.invokeNative(Native Method)
          at java.lang.reflect.Method.invoke(Method.java:525)
          at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1046)
          at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:862)
          at dalvik.system.NativeStart.main(Native Method)

If anyone can explain how to correct this

Possible duplicate of [What is a NullPointerException, and how do I fix it?](http://stackoverflow.com/questions/218384/what-is-a-nullpointerexception-and-how-do-i-fix-it) — Mehmet K, Apr 22 '17 at 15:08

mojth · Answer 1 · 2017-04-22T22:44:03.500

0

You get a NullPointerException in the onPostExecute methode. jsonArray and Lesetab are ok from what I can see. So Object o is probably null.

-Update- Based on the doInBackground method Code you provided I think there is an IOException thrown, but you don't notice it, because you catch it without handling it properly. String chainejson stays null and is returned. Then onPostExecute is called with null as parameter. This causing the NullPointerException.

To find out what's really going wrong could log the IOException.

edited Apr 22 '17 at 22:44

answered Apr 22 '17 at 14:59

mojth

44
3

And so I have to put that it is not null ? – Drägniir Apr 22 '17 at 15:06
What is the doInBackground methode of MonAsyncTaskHttp returning? I think the NullPointerException is thrown, when you call o.toString() – mojth Apr 22 '17 at 15:12
protected Object doInBackground(Object[] params) { if (MonAsyncTaskHttp.MonOkhttpclient == null) { MonAsyncTaskHttp.MonOkhttpclient = new OkHttpClient(); CookieManager cm = new CookieManager(); cm.setCookiePolicy(CookiePolicy.ACCEPT_ALL); CookieHandler.setDefault(cm); ; } – Drägniir Apr 22 '17 at 15:30
I can't see a return statement in your answer, is this the whole methode? – mojth Apr 22 '17 at 15:39
I will put all my code from the async task page in response – Drägniir Apr 22 '17 at 16:00
I updated my answer based on the new code you provided – mojth Apr 22 '17 at 16:40
How do you do that? – Drägniir Apr 22 '17 at 16:50
The Log class provides a methode for logging exceptions – mojth Apr 22 '17 at 16:57
[link](https://developer.android.com/reference/android/util/Log.html#e(java.lang.String, java.lang.String, java.lang.Throwable)) – mojth Apr 22 '17 at 17:07

Android error async task

1 Answers1