studio - onpreexecute method in android

NetworkOnMainThreadException durante el uso de AsyncTask

Question

Estoy creando una aplicación que usa Internet para recuperar información. Obtengo una NetworkOnMainThreadException cuando intenté ejecutarlo en 3.0 y versiones posteriores y, por lo tanto, he intentado configurarlo utilizando AsyncTask, pero todavía se da la excepción y no sé qué es lo que está mal. Curiosamente, leí en este hilo Android NetworkOnMainThreadException dentro de AsyncTask que si solo quita la android:targetSdkVersion="10" del archivo de manifiesto, podrá ejecutarse. Esto funciona, pero no creo que sea la solución adecuada para resolver el problema de esta manera.

Entonces, si alguien puede decirme lo que estoy haciendo mal con AsyncTask, realmente lo agradeceré. Además, si hay alguien que sepa por qué eliminar la declaración en el manifiesto hace que funcione, también estoy realmente interesado en eso.

Mi código es así: EDITAR: CÓDIGO ACTUALIZADO.

public class MainActivity extends Activity {

static ArrayList<Tumblr> tumblrs;
ListView listView;
TextView footer;
int offset = 0;
ProgressDialog pDialog;
View v;
String responseBody = null;
HttpResponse r;
HttpEntity e;
String searchUrl;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    requestWindowFeature(Window.FEATURE_NO_TITLE);
    getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
            WindowManager.LayoutParams.FLAG_FULLSCREEN);

    final ConnectivityManager conMgr = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
    final NetworkInfo activeNetwork = conMgr.getActiveNetworkInfo();
    if (activeNetwork != null && activeNetwork.isConnected()) {

        setContentView(R.layout.main);

        try {
            tumblrs = getTumblrs();
            listView = (ListView) findViewById(R.id.list);
            View v = getLayoutInflater().inflate(R.layout.footer_layout,
                    null);
            footer = (TextView) v.findViewById(R.id.tvFoot);
            listView.addFooterView(v);
            listView.setAdapter(new UserItemAdapter(this, R.layout.listitem));

        } catch (ClientProtocolException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } catch (JSONException e) {
            e.printStackTrace();
        }
        new GetChicks().execute();
        footer.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                new loadMoreListView().execute();
            }
        });

    } else {
        setContentView(R.layout.nonet);

    }

}

public class UserItemAdapter extends ArrayAdapter<Tumblr> {

    public UserItemAdapter(Context context, int imageViewResourceId) {
        super(context, imageViewResourceId, tumblrs);

    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        View v = convertView;
        if (v == null) {

            LayoutInflater vi = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            v = vi.inflate(R.layout.listitem, null);

        }

        Tumblr tumblr = tumblrs.get(position);
        if (tumblr != null) {

            ImageView image = (ImageView) v.findViewById(R.id.avatar);

            if (image != null) {
                image.setImageBitmap(getBitmap(tumblr.image_url));

            }
        }

        return v;
    }
}

public Bitmap getBitmap(String bitmapUrl) {
    try {
        URL url = new URL(bitmapUrl);
        return BitmapFactory.decodeStream(url.openConnection()
                .getInputStream());
    } catch (Exception ex) {
        return null;
    }
}

public ArrayList<Tumblr> getTumblrs() throws ClientProtocolException,
        IOException, JSONException {
    searchUrl = "http://api.tumblr.com/v2/blog/factsandchicks.com/posts?api_key=rTZsymOWtMudbb5tql2U20qQ5ooYLPYVNnL3COPpO2qBHDxJUu&limit=2&offset=0";

    ArrayList<Tumblr> tumblrs = new ArrayList<Tumblr>();
    return tumblrs;
}

private class GetChicks extends AsyncTask<Void, Void, Void> {

    @Override
    protected Void doInBackground(Void... unused) {
        // TODO Auto-generated method stub


                HttpClient client = new DefaultHttpClient();
                HttpGet get = new HttpGet(searchUrl);

                HttpResponse r = null;
                try {
                    r = client.execute(get);
                    int status = r.getStatusLine().getStatusCode();
                    if (status == 200) {
                        e = r.getEntity();
                        responseBody = EntityUtils.toString(e);
                    }
                } catch (ClientProtocolException e1) {
                    // TODO Auto-generated catch block
                    e1.printStackTrace();
                } catch (IOException e1) {
                    // TODO Auto-generated catch block
                    e1.printStackTrace();
                }

                JSONObject jsonObject;
                try {
                    jsonObject = new JSONObject(responseBody);

                    JSONArray posts = jsonObject.getJSONObject("response")
                            .getJSONArray("posts");

                    for (int i = 0; i < posts.length(); i++) {
                        JSONArray photos = posts.getJSONObject(i)
                                .getJSONArray("photos");
                        for (int j = 0; j < photos.length(); j++) {
                            JSONObject photo = photos.getJSONObject(j);
                            String url = photo.getJSONArray("alt_sizes")
                                    .getJSONObject(0).getString("url");

                            Tumblr tumblr = new Tumblr(url);
                            tumblrs.add(tumblr);

                        }
                    }

                } catch (JSONException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }



        return null;
    }

}

public class Tumblr {

    public String image_url;

    public Tumblr(String url) {

        this.image_url = url;

    }
}

private class loadMoreListView extends AsyncTask<Void, Void, Void> {

    @Override
    protected void onPreExecute() {
        // Showing progress dialog before sending http request
        pDialog = new ProgressDialog(MainActivity.this);
        pDialog.setMessage("More chicks coming up..");
        pDialog.setIndeterminate(true);
        pDialog.setCancelable(false);
        pDialog.show();
    }

    @Override
    protected Void doInBackground(Void... unused) {
        // TODO Auto-generated method stub

                // increment current page
                offset += 2;

                // Next page request
                tumblrs.clear();
                String searchUrl = "http://api.tumblr.com/v2/blog/factsandchicks.com/posts?api_key=rTZsymOWtMudbb5tql2U20qQ5ooYLPYVNnL3COPpO2qBHDxJUu&limit=2&offset="
                        + offset;

                HttpClient client = new DefaultHttpClient();
                HttpGet get = new HttpGet(searchUrl);

                HttpResponse r = null;
                try {
                    r = client.execute(get);
                    int status = r.getStatusLine().getStatusCode();
                    if (status == 200) {
                        HttpEntity e = r.getEntity();
                        responseBody = EntityUtils.toString(e);
                    }
                } catch (ClientProtocolException e1) {
                    // TODO Auto-generated catch block
                    e1.printStackTrace();
                } catch (IOException e1) {
                    // TODO Auto-generated catch block
                    e1.printStackTrace();
                }

                JSONObject jsonObject;
                try {
                    jsonObject = new JSONObject(responseBody);

                    JSONArray posts = jsonObject.getJSONObject("response")
                            .getJSONArray("posts");

                    for (int i = 0; i < posts.length(); i++) {
                        JSONArray photos = posts.getJSONObject(i)
                                .getJSONArray("photos");
                        for (int j = 0; j < photos.length(); j++) {
                            JSONObject photo = photos.getJSONObject(j);
                            String url = photo.getJSONArray("alt_sizes")
                                    .getJSONObject(0).getString("url");

                            Tumblr tumblr = new Tumblr(url);
                            tumblrs.add(tumblr);

                        }
                    }

                } catch (JSONException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }

                // Setting new scroll position
                listView.setSelectionFromTop(0, 0);



        return null;
    }

    protected void onPostExecute(Void unused) {
        pDialog.dismiss();

    }

}

@Override
public boolean onCreateOptionsMenu(android.view.Menu menu) {
    // TODO Auto-generated method stub
    super.onCreateOptionsMenu(menu);
    MenuInflater blowUp = getMenuInflater();
    blowUp.inflate(R.menu.cool_menu, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // TODO Auto-generated method stub
    switch (item.getItemId()) {
    case R.id.aboutUs:
        Intent i = new Intent("com.example.example.ABOUT");
        startActivity(i);

        break;
    case R.id.refresh:
        Intent f = new Intent(MainActivity.this, MainActivity.class);
        startActivity(f);
        finish();
        break;
    case R.id.exit:
        finish();
        break;
    }
    return false;
}

}

El registro se ve así:

 10-07 10:27:56.163: E/AndroidRuntime(923): FATAL EXCEPTION: AsyncTask #2
 10-07 10:27:56.163: E/AndroidRuntime(923): java.lang.RuntimeException: An error  occured while executing doInBackground()
 10-07 10:27:56.163: E/AndroidRuntime(923):     at android.os.AsyncTask$3.done(AsyncTask.java:278)
 10-07 10:27:56.163: E/AndroidRuntime(923):     at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:273)
 10-07 10:27:56.163: E/AndroidRuntime(923):     at java.util.concurrent.FutureTask.setException(FutureTask.java:124)
 10-07 10:27:56.163: E/AndroidRuntime(923):     at  java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:307)
 10-07 10:27:56.163: E/AndroidRuntime(923):     at  java.util.concurrent.FutureTask.run(FutureTask.java:137)
 10-07 10:27:56.163: E/AndroidRuntime(923):     at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:208)
 10-07 10:27:56.163: E/AndroidRuntime(923):     at  java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
 10-07 10:27:56.163: E/AndroidRuntime(923):     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
 10-07 10:27:56.163: E/AndroidRuntime(923):     at java.lang.Thread.run(Thread.java:856)
 10-07 10:27:56.163: E/AndroidRuntime(923): Caused by: android.view.ViewRootImpl$CalledFromWrongThreadException: Only the original thread that  created a view hierarchy can touch its views.
 10-07 10:27:56.163: E/AndroidRuntime(923):     at android.view.ViewRootImpl.checkThread(ViewRootImpl.java:3939)
 10-07 10:27:56.163: E/AndroidRuntime(923):     at android.view.ViewRootImpl.requestLayout(ViewRootImpl.java:701)
 10-07 10:27:56.163: E/AndroidRuntime(923):     at android.view.View.requestLayout(View.java:12555)
 10-07 10:27:56.163: E/AndroidRuntime(923):     at android.view.View.requestLayout(View.java:12555)
 10-07 10:27:56.163: E/AndroidRuntime(923):     at android.view.View.requestLayout(View.java:12555)
 10-07 10:27:56.163: E/AndroidRuntime(923):     at android.view.View.requestLayout(View.java:12555)
 10-07 10:27:56.163: E/AndroidRuntime(923):     at android.view.View.requestLayout(View.java:12555)
 10-07 10:27:56.163: E/AndroidRuntime(923):     at android.widget.AbsListView.requestLayout(AbsListView.java:1690)
 10-07 10:27:56.163: E/AndroidRuntime(923):     at android.widget.ListView.setSelectionFromTop(ListView.java:1928)
 10-07 10:27:56.163: E/AndroidRuntime(923):     at com.fansheroid.facts.chicks.MainActivity$loadMoreListView.doInBackground(MainActivity.java:291)
 10-07 10:27:56.163: E/AndroidRuntime(923):     at com.fansheroid.facts.chicks.MainActivity$loadMoreListView.doInBackground(MainActivity.java:1)
 10-07 10:27:56.163: E/AndroidRuntime(923):     at android.os.AsyncTask$2.call(AsyncTask.java:264)
 10-07 10:27:56.163: E/AndroidRuntime(923):     at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
 10-07 10:27:56.163: E/AndroidRuntime(923):     ... 5 more

Answer 1

Está llamando runOnUiThread() método runOnUiThread() mientras AsyncTask solía ejecutar cosas en otro subproceso para evitar interceptar el subproceso de la interfaz de usuario para procesos largos en el método doInBackground() . Creo que eliminar runOnUiThread() haría el trabajo.