java.lang.RuntimeException: An error occured while executing doInBackground()

Question

Sometimes i get this crash error in my app

java.lang.RuntimeException: An error occured while executing doInBackground()

This is the full logCat:

java.lang.RuntimeException: An error occured while executing doInBackground()
at android.os.AsyncTask$3.done(AsyncTask.java:200)
at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:274)
at java.util.concurrent.FutureTask.setException(FutureTask.java:125)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:308)
at java.util.concurrent.FutureTask.run(FutureTask.java:138)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1088)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:581)
at java.lang.Thread.run(Thread.java:1019)
Caused by: java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare()
at android.os.Handler.<init>(Handler.java:121)
at android.widget.Toast.<init>(Toast.java:68)
at android.widget.Toast.makeText(Toast.java:231)
at kostas.menu.olympiakos.nea.loadFeed(nea.java:84)
at kostas.menu.olympiakos.nea.access$1(nea.java:75)
at kostas.menu.olympiakos.nea$BackgroundAsyncTask_nea.doInBackground(nea.java:242)
at kostas.menu.olympiakos.nea$BackgroundAsyncTask_nea.doInBackground(nea.java:1)
at android.os.AsyncTask$2.call(AsyncTask.java:185)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:306)
... 4 more

and this is my .nea class code:

package kostas.menu.olympiakos;


import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;

import android.app.Dialog;
import android.app.ListActivity;
import android.app.ProgressDialog;
import android.content.Context;
import android.content.Intent;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.net.Uri;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.Window;
import android.view.animation.AlphaAnimation;
import android.view.animation.Animation;
import android.view.animation.AnimationSet;
import android.view.animation.LayoutAnimationController;
import android.view.animation.TranslateAnimation;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.TextView;
import android.widget.Toast;


public class nea extends ListActivity{
    private List<Message> messages; 




    List<String> des = new ArrayList<String>();//to prosthesa gia na anoigei to keimeno sto alert
    List<String> text = new ArrayList<String>();//to prosthesa gia na anoigei o titlos sto alert
    List<URL> url = new ArrayList<URL>();//to prosthesa gia to koumpi pou pigainei sto link

    List<String> imgl = new ArrayList<String>();//to prosthesa gia na anoigei to keimeno sto alert

    @Override 
    public void onCreate(Bundle icicle) {   
        super.onCreate(icicle);
        setContentView(R.layout.main2);

        if(isInternetOn()) {
            new BackgroundAsyncTask_nea().execute();
            }else{
             Toast.makeText(nea.this,R.string.no_connection, Toast.LENGTH_SHORT).show();
             finish();
            }



    }


    private void loadFeed(AsyncTask<Void, Void, Void> asyncTask){
        try{ 
            BaseFeedParser parser = new BaseFeedParser();
            messages = parser.parse();

            }
         catch (Throwable t){
              Log.e("OSFP.News",t.getMessage(),t);

                Toast.makeText(nea.this, "Χρειάζεστε σύνδεση στο internet",
                        Toast.LENGTH_SHORT).show();
                finish();

            }
    }


    private void displayRss(){

        ArrayList<HashMap<String, String>> List_nea = new ArrayList<HashMap<String, String>>(messages.size());


        for (Message msg : messages){

            des.add(msg.getDescription());// keimeno
            text.add(msg.getTitle());// titlos
            url.add(msg.getLink());// link
            imgl.add(msg.getImgLink());

        HashMap<String, String> map = new HashMap<String, String>();
        map.put("name", msg.getTitle());
        map.put("date", msg.getDate());     


        List_nea.add(map);
        ListAdapter mSchedule = new SimpleAdapter(this, List_nea, R.layout.row,
                new String[] {"name", "date"}, new int[] {R.id.TextView01, R.id.TextView02});
        this.setListAdapter(mSchedule);
        }

    AnimationSet set = new AnimationSet(true);

    Animation animation = new AlphaAnimation(0.0f, 1.0f);
    animation.setDuration(400);
    set.addAnimation(animation);

    animation = new TranslateAnimation(
        Animation.RELATIVE_TO_SELF, 0.0f,Animation.RELATIVE_TO_SELF, 0.0f,
        Animation.RELATIVE_TO_SELF, -1.0f,Animation.RELATIVE_TO_SELF, 0.0f
    );

    animation.setDuration(400);
    set.addAnimation(animation);
    LayoutAnimationController controller = new LayoutAnimationController(set, 0.5f);
    ListView listViewn = getListView();        
    listViewn.setLayoutAnimation(controller);

    }



    protected void onListItemClick(ListView l, View v, final int position, long id) {



        super.onListItemClick(l, v, position, id);
        Dialog dialog = new Dialog(this);
       String description = des.get(position).toString().replaceAll("\\<.*?>","");
       String imagee=imgl.get(position).toString();
        final URL link = url.get(position);
        dialog.requestWindowFeature(Window.FEATURE_NO_TITLE); 
            dialog.setContentView(R.layout.single);
            dialog.setCancelable(true);
            Toast msg = Toast.makeText(nea.this, "The url is  :  "+imagee, Toast.LENGTH_LONG);
            msg.show();
//xrisimopoiisa toast gia na elegxw poio link pernw apo to site



            TextView title_dialog = (TextView) dialog.findViewById(R.id.title_dialog);
            title_dialog.setText(text.get(position));


            TextView text = (TextView) dialog.findViewById(R.id.descr);
            text.setText(description);


            ImageView image1 = (ImageView) dialog.findViewById(R.id.image1);


            try {
                //where imageUrl is what you pulled out from the rss feed
                Bitmap bitmap = BitmapFactory.decodeStream((InputStream)new URL(imagee).getContent());
                image1.setImageBitmap(bitmap); 
              } catch (MalformedURLException e) {
               //log exception here
              } catch (IOException e) {
                //log exception here
              }      
            Button btnt = (Button) dialog.findViewById(R.id.btnrss);//ti kanei to koumpi otan to patas gia to link
            btnt.setOnClickListener(new View.OnClickListener() {
                public void onClick (View view) {

                    Intent viewMessage = new Intent(Intent.ACTION_VIEW, Uri.parse(link.toExternalForm()));
                    startActivityForResult(viewMessage, 0);

                }  

            });           

            dialog.show();
    }

        //options menu
    @Override
    public boolean onCreateOptionsMenu(Menu menu2) {
        MenuInflater inflater = getMenuInflater();
        inflater.inflate(R.menu.menu2, menu2);
        return true;
    }  

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) {
        case R.id.refresh:
            new BackgroundAsyncTask_nea().execute();
            break;


        }
        return true;
    }

    public class BackgroundAsyncTask_nea extends
       AsyncTask<Void, Void, Void> {
          private ProgressDialog dialog;
        int myProgress;   

        @Override
        protected void onPostExecute(Void result) {

            displayRss();
             dialog.dismiss();

        }

        @Override
        protected void onPreExecute() {
            // TODO Auto-generated method stub
              dialog = ProgressDialog.show(nea.this, "", "Loading. Please wait...", true);
            myProgress = 0;
        }

        protected void onProgressUpdate(Integer... progress) {
          // TODO Auto-generated method stub
          //super.onProgressUpdate(values);

            dialog.setProgress(progress[0]);
         }

        @Override
        protected Void doInBackground(Void... arg0) {
            // TODO Auto-generated method stub

            loadFeed(this);
            return null;
        }



    }


    public final boolean isInternetOn() {
        ConnectivityManager connec =  (ConnectivityManager)getSystemService(Context.CONNECTIVITY_SERVICE);
        // ARE WE CONNECTED TO THE NET
        if ( connec.getNetworkInfo(0).getState() == NetworkInfo.State.CONNECTED ||
        connec.getNetworkInfo(0).getState() == NetworkInfo.State.CONNECTING ||
        connec.getNetworkInfo(1).getState() == NetworkInfo.State.CONNECTING ||
        connec.getNetworkInfo(1).getState() == NetworkInfo.State.CONNECTED ) {
        // MESSAGE TO SCREEN FOR TESTING (IF REQ)
        //Toast.makeText(this, connectionType + ” connected”, Toast.LENGTH_SHORT).show();
        return true;
        } else if ( connec.getNetworkInfo(0).getState() == NetworkInfo.State.DISCONNECTED ||  connec.getNetworkInfo(1).getState() == NetworkInfo.State.DISCONNECTED  ) {
        //System.out.println(“Not Connected”);
        return false;
        }
        return false;
        }
}

Why am i getting this error?How can i solve it?Thanks :)

EDIT:

Public void toast_doInBck(View view) {
        // Do something long
        Runnable runnable = new Runnable() {
            @Override
            public void run() {
                for (int i = 0; i <= 10; i++) {
                    Toast.makeText(nea.this,R.string.no_connection, Toast.LENGTH_SHORT).show();
                    handler.post(new Runnable() {
                        @Override
                        public void run() {
                        }
                    });
                }
            }
        };
        new Thread(runnable).start();
    }

EDIT2:

    private void loadFeed(AsyncTask<Void, Void, Void> asyncTask){
        try{ 
            BaseFeedParser parser = new BaseFeedParser();
            messages = parser.parse();

            }
         catch (Throwable t){
              Log.e("OSFP.News",t.getMessage(),t);
Looper.prepare();
                Toast.makeText(nea.this, "Παρακαλώ προσπαθήστε αργότερα..",
                        Toast.LENGTH_SHORT).show();
                finish();
                Looper.loop();

            }
    }

Did you read the message? Can't create handler inside thread that has not called Looper.prepare() — SLaks
– SLaks, Commented Jan 20, 2012 at 18:41
Yes,i read it but i dont know how to solve it!Just call Looper.prepare before my toast,and then Looper.Loop after it? — user1156210
– user1156210, Commented Jan 20, 2012 at 18:42

Bruno Oliveira · Accepted Answer · 2012-01-20 18:42:26Z

29

This is probably because you're trying to display something on doInBackground(). doInBackground runs in a worker thread which cannot do any UI work (including showing Toasts, which is what you're doing). Instead, all UI work should be done on onPostExecute().

answered Jan 20, 2012 at 18:42

Bruno Oliveira

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1 Comment

user1156210 Over a year ago

thanks for your answer!The UI is done on onPostExecute!I just throw a toast in the doInBackground if there is a problem with my connection.Isn't that possible?

Joachim Isaksson · Accepted Answer · 2012-01-20 19:39:26Z

6

You can't do any GUI work on a background thread. Instead you should post a Runnable to a handler created in the GUI thread to make your Toast execute on the correct thread.

EDIT: Since the homework tag was removed, I'll give an outline how to do it;

new() up a Handler in your GUI thread (onCreate is a good place) and save it in a member variable, say "handler".
Move showing your Toast to a Runnable (anonymous class is pretty good for this)
To show the toast, do a handler.post() with your Runnable as a parameter. The Runnable will execute in the GUI thread.

For a complete example, see this article.

edited Jan 20, 2012 at 19:39

answered Jan 20, 2012 at 18:51

Joachim Isaksson

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3 Comments

user1156210 Over a year ago

i m sorry but i need some more help.May i create something like my edit on the answer?

user1156210 Over a year ago

please,i have updated my answer (EDIT2)with a working solution i found..Could you please tell me if this way is correct?

Joachim Isaksson Over a year ago

You still cannot run loadFeed from a background thread, you need to put a handler.post() in the catch block, and give it a Runnable which calls your Toast methods in its run() method.

kabuko · Accepted Answer · 2012-01-20 18:42:14Z

1

You're showing a Toast in loadFeed which is called in the doInBackground part of your AsyncTask. You shouldn't access the UI from there.

answered Jan 20, 2012 at 18:42

kabuko

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1 Comment

user1156210 Over a year ago

Is there any way to have a toast if the try{} of the loadFeed() is not working?

user370305 · Accepted Answer · 2012-01-20 18:52:01Z

1

I think In this code Toast make problem for you,

catch (Throwable t){
              Log.e("OSFP.News",t.getMessage(),t);

                Toast.makeText(nea.this, "Χρειάζεστε σύνδεση στο internet",
                        Toast.LENGTH_SHORT).show();
                finish();

            }

Because you are trying to do UI operation from worker thread of AsyncTask this will never allowed..

UPDATE: If you want to update something from the doInBackGround() of AsyncTask use publishProgress(Progress...) and onProgressUpdate(Progress...).

edited Jan 20, 2012 at 18:52

answered Jan 20, 2012 at 18:46

user370305

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