Network error and Async confusion

Question

I have been working on this app for awhile now and I am on the verge of completion however This error:

java.lang.RuntimeException: Unable to start activity ComponentInfo{org.marsfirst.mars_app/org.marsfirst.mars_app.TeamNews}: android.os.NetworkOnMainThreadException at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2413) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2471) at android.app.ActivityThread.access$900(ActivityThread.java:175) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1308) at android.os.Handler.dispatchMessage(Handler.java:102) at android.os.Looper.loop(Looper.java:146) at android.app.ActivityThread.main(ActivityThread.java:5602) at java.lang.reflect.Method.invokeNative(Native Method) at java.lang.reflect.Method.invoke(Method.java:515) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1283) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1099) at dalvik.system.NativeStart.main(Native Method) Caused by: android.os.NetworkOnMainThreadException at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1166) at com.android.org.conscrypt.OpenSSLSocketImpl.close(OpenSSLSocketImpl.java:1009) at org.apache.http.impl.SocketHttpClientConnection.close(SocketHttpClientConnection.java:205) at org.apache.http.impl.conn.DefaultClientConnection.close(DefaultClientConnection.java:161) at org.apache.http.impl.conn.tsccm.AbstractConnPool.closeConnection(AbstractConnPool.java:320) at org.apache.http.impl.conn.tsccm.AbstractConnPool.shutdown(AbstractConnPool.java:296) at org.apache.http.impl.conn.tsccm.ConnPoolByRoute.shutdown(ConnPoolByRoute.java:670) at org.apache.http.impl.conn.tsccm.ThreadSafeClientConnManager.shutdown(ThreadSafeClientConnManager.java:256) at com.parse.ParseRequest.initialize(ParseRequest.java:118) at com.parse.Parse.initialize(Parse.java:109) at org.marsfirst.mars_app.TeamNews.onCreate(TeamNews.java:41) at android.app.Activity.performCreate(Activity.java:5451) at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1093) at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2377)

After doing alot of research on the Issue I know I need to put the following code in my app:

AsyncTask<Void, Void, Void> task = new AsyncTask<Void, Void, Void>() {

         @Override
         protected Void doInBackground(Void... params) {
            Parse.initialize(this, "Key",
            "Key");;
         }

      };

However I am unsure where to place the code.

My MainPage.Java:

    package org.marsfirst.mars_app;

    import android.app.Activity;
    import android.content.Intent;
    import android.os.AsyncTask;
    import android.os.Bundle;
    import android.view.View;
    import android.widget.ImageView;

    public class MainPage extends Activity {
        @Override
        protected void onCreate(Bundle savedInstanceState) {

            super.onCreate(savedInstanceState);
            setContentView(R.layout.mainpage);

            ImageView website = (ImageView) findViewById(R.id.imageButton6);
            website.setOnClickListener(new View.OnClickListener() {

                @Override
                public void onClick(View arg0) {
                    // TODO Auto-generated method stub
                    new CallWebpage().execute();
                }
            });
            ImageView logo1 = (ImageView) findViewById(R.id.imageButton7);
            logo1.setOnClickListener(new View.OnClickListener() {

                @Override
                public void onClick(View arg0) {
                    // TODO Auto-generated method stub
                    new CallEvent().execute();
                }
            });
            ImageView contactpage = (ImageView) findViewById(R.id.imagebutton8);
            contactpage.setOnClickListener(new View.OnClickListener() {

                @Override
                public void onClick(View arg0) {
                    // TODO Auto-generated method stub
                    new CallContact().execute();
                }
            });

            ImageView teamNews = (ImageView) findViewById(R.id.imagebutton1);
            teamNews.setOnClickListener(new View.OnClickListener() {

                @Override
                public void onClick(View arg0) {
                    // TODO Auto-generated method stub
                    new CallTeamNews().execute();
                }
            });

            ImageView mechPage = (ImageView) findViewById(R.id.imageButton2);
            mechPage.setOnClickListener(new View.OnClickListener() {

                @Override
                public void onClick(View arg0) {
                    // TODO Auto-generated method stub
                    new CallMechPage().execute();
                }
            });

            ImageView driveNews = (ImageView) findViewById(R.id.imagebutton3);
            driveNews.setOnClickListener(new View.OnClickListener() {

                @Override
                public void onClick(View arg0) {
                    // TODO Auto-generated method stub
                    new CallDriveNews().execute();
                }
            });

            ImageView oprPage = (ImageView) findViewById(R.id.imagebutton4);
            oprPage.setOnClickListener(new View.OnClickListener() {

                @Override
                public void onClick(View arg0) {
                    // TODO Auto-generated method stub
                    new CallOprPage().execute();
                }
            });

            ImageView ProgramingPage = (ImageView) findViewById(R.id.imagebutton5);
            ProgramingPage.setOnClickListener(new View.OnClickListener() {

                @Override
                public void onClick(View arg0) {
                    // TODO Auto-generated method stub
                    new CallProgramingPage().execute();
                }
            });
            ImageView food = (ImageView) findViewById(R.id.imageButton9);
            food.setOnClickListener(new View.OnClickListener() {

                @Override
                public void onClick(View arg0) {
                    // TODO Auto-generated method stub
                    new CallFood().execute();
                }
            });
            ImageView travel = (ImageView) findViewById(R.id.imagebutton10);
            travel.setOnClickListener(new View.OnClickListener() {

                @Override
                public void onClick(View arg0) {
                    // TODO Auto-generated method stub
                    new CallTravel().execute();
                }
            });

        }

        public class CallWebpage extends AsyncTask<Void, Void, String> {
            protected String doInBackground(Void... urls) {
                Intent intent = new Intent(MainPage.this, Webpage.class);
                MainPage.this.startActivity(intent);
                return "";

            }
        }

        public class CallTeamNews extends AsyncTask<Void, Void, String> {
            protected String doInBackground(Void... urls) {
                Intent intent = new Intent(MainPage.this, TeamNews.class);
                MainPage.this.startActivity(intent);
                return "";
            }
        }

        public class CallOprPage extends AsyncTask<Void, Void, String> {
            protected String doInBackground(Void... urls) {
                Intent intent = new Intent(MainPage.this, OprPage.class);
                MainPage.this.startActivity(intent);
                return "";
            }
        }

        public class CallDriveNews extends AsyncTask<Void, Void, String> {
            protected String doInBackground(Void... urls) {
                Intent intent = new Intent(MainPage.this, DriveNews.class);
                MainPage.this.startActivity(intent);
                return "";
            }
        }

        public class CallMechPage extends AsyncTask<Void, Void, String> {
            protected String doInBackground(Void... urls) {
                Intent intent = new Intent(MainPage.this, MechPage.class);
                MainPage.this.startActivity(intent);
                return "";
            }
        }

        public class CallProgramingPage extends AsyncTask<Void, Void, String> {
            protected String doInBackground(Void... urls) {
                Intent intent = new Intent(MainPage.this, ProgramingPage.class);
                MainPage.this.startActivity(intent);
                return "";
            }

        }

        public class CallEvent extends AsyncTask<Void, Void, String> {
            protected String doInBackground(Void... urls) {
                Intent intent = new Intent(MainPage.this, Event.class);
                MainPage.this.startActivity(intent);
                return "";
            }

        }

        public class CallContact extends AsyncTask<Void, Void, String> {
            protected String doInBackground(Void... urls) {
                Intent intent = new Intent(MainPage.this, Contact.class);
                MainPage.this.startActivity(intent);
                return "";
            }

        }

        public class CallFood extends AsyncTask<Void, Void, String> {
            protected String doInBackground(Void... urls) {
                Intent intent = new Intent(MainPage.this, Food.class);
                MainPage.this.startActivity(intent);
                return "";
            }

        }
        public class CallTravel extends AsyncTask<Void, Void, String> {

            protected String doInBackground(Void... urls) {
                Intent intent = new Intent(MainPage.this, Travel.class);
                MainPage.this.startActivity(intent);
                return "";
            }

        }


    }
Would I place the the code in somewhere  like this:

    public class CallProgramingPage extends AsyncTask<Void, Void, String> {
                protected String doInBackground(Void... urls) {
                    Intent intent = new Intent(MainPage.this, ProgramingPage.class);
                    MainPage.this.startActivity(intent);
                    return "";
                }

            }

and if so how because when I did I received many errors.
However would it be better to set up an Async Task in my actual activity that uses parse:

package org.marsfirst.mars_app;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.StreamCorruptedException;

import android.app.Activity;
import android.content.Context;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.os.AsyncTask;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.widget.TextView;
import android.widget.Toast;

import com.parse.GetCallback;
import com.parse.Parse;
import com.parse.ParseException;
import com.parse.ParseObject;
import com.parse.ParseQuery;



public class TeamNews extends Activity {

    private Context c;
    private ParseProxyObject saved;
    private TextView title, date, content;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        Parse.initialize(this, "QmmXYAxVVSoT7MGlE3ZcAseCoLehfZko3BZJbo1P",
                "SQHTLKcpNKDCLZWTgfOOFPEcmFYkdmWywKNProWG");
        setContentView(R.layout.announcements);

        c = getApplicationContext();

        new CallUpdate(TeamNews.this).execute();

        title = (TextView) findViewById(R.id.textView1);
        date = (TextView) findViewById(R.id.textView2);
        content = (TextView) findViewById(R.id.textView3);

        saved = (ParseProxyObject) readObjectFromMemory("announce");
        setTexts(saved);
        if (title.getText().equals("Connect to internet and press refresh.")) {
            try {
                Thread.sleep(100);
            } catch (InterruptedException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }

    }

    @Override
    public void onResume() {
        super.onResume();
        c = getApplicationContext();
        if (isNetworkAvailable())
            (new CallUpdate(TeamNews.this)).execute();

        title = (TextView) findViewById(R.id.textView1);
        date = (TextView) findViewById(R.id.textView2);
        content = (TextView) findViewById(R.id.textView3);

        saved = (ParseProxyObject) readObjectFromMemory("announce");
        setTexts(saved);

    }

    public void setTexts(ParseProxyObject saved) {
        if (saved == null) {
            emptyTexts();
            title.setText("Connect to internet and press refresh.");
            return;
        }
        String format = "\t";

        title.setText(format + saved.getString("name"));

        String format2 = "\t";

        date.setText(format2 + saved.getString("date_updated"));

        String format3 = "\t";

        content.setText(format3 + saved.getString("content_1"));
    }

    public ParseProxyObject readObjectFromMemory(String filename) {
        FileInputStream fis;
        ParseProxyObject object = null;
        try {
            fis = openFileInput(filename);
            ObjectInputStream is = new ObjectInputStream(fis);
            object = (ParseProxyObject) is.readObject();
            is.close();
        } catch (FileNotFoundException e) {
            e.printStackTrace();

        } catch (StreamCorruptedException e) {
            e.printStackTrace();

        } catch (IOException e) {
            e.printStackTrace();

        } catch (ClassNotFoundException e) {
            e.printStackTrace();

        }
        return object;
    }

    public void emptyTexts() {
        title.setText("");

        date.setText("");

        content.setText("");

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu items for use in the action bar
        MenuInflater inflater = getMenuInflater();
        inflater.inflate(R.menu.main, menu);
        return super.onCreateOptionsMenu(menu);
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle presses on the action bar items
        switch (item.getItemId()) {
        case R.id.action_refresh_k:
            (new CallUpdate(c)).execute();
            return true;
        default:
            return super.onOptionsItemSelected(item);
        }
    }

    public class CallUpdate extends AsyncTask<Void, Void, String> {
        private Context c;

        public CallUpdate(Context newC) {
            c = newC;
        }

        @Override
        protected void onPreExecute() {
            View v = findViewById(R.id.action_refresh_k);
            if (v != null)
                v.setVisibility(View.GONE);

        }

        protected String doInBackground(Void... urls) {
            ParseQuery<ParseObject> query;
            saved = (ParseProxyObject) readObjectFromMemory("announce");
            query = ParseQuery.getQuery("Announcements");
            query.getInBackground("1XLhLinldW", new GetCallback<ParseObject>() {
                public void done(ParseObject object, ParseException e) {
                    if (e == null) {
                        if (object != null
                                && (saved == null || !(object.getInt("version") == saved
                                        .getInt("version")))) {
                            saved = new ParseProxyObject(object);
                            (new CallSave(c, saved, "announce")).execute();

                        }

                    } else {
                        // something went wrong
                        return;
                    }
                }
            });

            return "";
        }

        protected void onPostExecute(String result) {
            View v = findViewById(R.id.action_refresh_k);
            if (v != null)
                v.setVisibility(View.VISIBLE);

            saved = (ParseProxyObject) readObjectFromMemory("announce");
            setTexts(saved);
        }

    }

    public void writeObjectToMemory(String filename, ParseProxyObject object) {
        FileOutputStream fos;
        try {
            fos = c.openFileOutput(filename, Context.MODE_PRIVATE);
            ObjectOutputStream os = new ObjectOutputStream(fos);
            os.writeObject(object);
            os.close();
        } catch (FileNotFoundException e) {
            e.printStackTrace();

        } catch (IOException e) {
            e.printStackTrace();

        }
    }

    public void makeToast(String text) {
        int duration = Toast.LENGTH_SHORT;

        Toast toast = Toast.makeText(c, text, duration);
        toast.show();
    }

    public class CallSave extends AsyncTask<Void, Void, String> {
        Context c;
        ParseProxyObject object;
        String filename;

        public CallSave(Context newC, ParseProxyObject newObject,
                String newFileName) {
            c = newC;
            object = newObject;
            filename = newFileName;
        }

        @Override
        protected void onPreExecute() {

        }

        @Override
        protected String doInBackground(Void... urls) {
            FileOutputStream fos;
            try {
                fos = openFileOutput(filename, Context.MODE_PRIVATE);
                ObjectOutputStream os = new ObjectOutputStream(fos);
                os.writeObject(((ParseProxyObject) object));
                os.flush();
                os.close();
            } catch (FileNotFoundException e) {
                e.printStackTrace();

            } catch (IOException e) {
                e.printStackTrace();

            }
            return "";
        }

        @Override
        protected void onPostExecute(String result) {

        }

    }

    private boolean isNetworkAvailable() {
        ConnectivityManager connectivityManager = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo activeNetworkInfo = connectivityManager
                .getActiveNetworkInfo();
        return activeNetworkInfo != null && activeNetworkInfo.isConnected();
    }
}

Please Help me I am completely lost and I don't know where else that I can put it and If I have the wrong style of code please tell me. I am still learning and self taught so please bare with my Idiocy. Thank you.

Where, in which moment, do you need to do Parse.initialize(this, "Key", "Key");? — joao2fast4u, Jul 28 '14 at 02:40

score 0 · Answer 1 · edited May 23 '17 at 12:29

You need to put all your networking code inside DoInBackground Method. there are four methods available for async onPreExecute which runs on UiThread and do all updations you want before entering doInBackgound. doInBackground which does all the work off the UI thread and you will not get network on mainThread Exception. and onPostExecute once doinbackground has finished this is called and you can show the results and update UI because onPostExecute runs on UIThread and there are some other available also like oncanceled etc.

AsyncTask enables proper and easy use of the UI thread. This class allows to perform background operations and publish results on the UI thread without having to manipulate threads and/or handlers.

AsyncTask is designed to be a helper class around Thread and Handler and does not constitute a generic threading framework. AsyncTasks should ideally be used for short operations (a few seconds at the most.) If you need to keep threads running for long periods of time, it is highly recommended you use the various APIs provided by the java.util.concurrent pacakge such as Executor, ThreadPoolExecutor and FutureTask.

An asynchronous task is defined by a computation that runs on a background thread and whose result is published on the UI thread. An asynchronous task is defined by 3 generic types, called Params, Progress and Result, and 4 steps, called onPreExecute, doInBackground, onProgressUpdate and onPostExecute.

You can Check out These Posts they are good Examples of AsyncTasks all your confusions are gona be solved :)

http://www.vogella.com/tutorials/AndroidBackgroundProcessing/article.html

AsyncTask Android example

http://android.programmerguru.com/android-asynctask-example/

for more information.

http://developer.android.com/reference/android/os/AsyncTask.html