If you import the facebook SDK library, the code works (ignore the deprecated methods for now lol) and there are no errors or warnings.

However, when I run my facebook app on my Android 2.2 or 4.2 emulator, the app crashes either upon opening or after the log on screen. Why?

Is it because I'm not implementing Async Task? If so, how does that work?

Here's my code:

package com.sara.facebookappl;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;

import org.json.JSONException;
import org.json.JSONObject;


import android.app.Activity;
import android.content.Intent;
import android.content.SharedPreferences;
import android.content.SharedPreferences.Editor;
import android.os.Bundle;
import android.os.StrictMode;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;

import com.facebook.android.DialogError;
import com.facebook.android.Facebook;
import com.facebook.android.Facebook.DialogListener;
import com.facebook.android.FacebookError;
import com.facebook.android.Util;

public  class MainActivity extends Activity implements OnClickListener, DialogListener {

    Facebook fb; 
    ImageView button; 
    SharedPreferences sp; 
    TextView welcome; 
    Button post; 

    @SuppressWarnings("deprecation")
    @Override
    protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);

            post=(Button)findViewById(R.id.button1);

            String APP_ID = getString(R.string.APP_ID);
            fb= new Facebook(APP_ID);

            sp =getPreferences(MODE_PRIVATE);
            String access_token=sp.getString("access_token", null);
            long expires=sp.getLong("access_expires", 0);

            if (access_token !=null) {
                    fb.setAccessToken(access_token);
            }
            if(expires !=0) {
                    fb.setAccessExpires(expires);
            }


            button=(ImageView)findViewById(R.id.login);
            button.setOnClickListener((OnClickListener) this);
            updateButtonImage();

    }

    @SuppressWarnings("deprecation")
    private void updateButtonImage() {
            // TODO Auto-generated method stub

            post.setVisibility(Button.VISIBLE);
            button.setImageResource(R.drawable.com_facebook_loginbutton_blue);
            //logout button

            if (fb.isSessionValid()) {
                    button.setImageResource(R.drawable.com_facebook_loginbutton_blue);
                    // ^logout button

            JSONObject obj=null;
            URL img_url =null;

            try {
            String jsonUser= fb.request("me");
            obj = Util.parseJson(jsonUser);
            String id=obj.optString("id"); 
            String name = obj.optString("name");
            welcome.setText("Welcome, " + name);
            }catch(FacebookError e) {
                    e.printStackTrace();

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

            }else {
                    post.setVisibility(Button.VISIBLE);
                    button.setImageResource(R.drawable.com_facebook_loginbutton_blue);
            }
    }

    @SuppressWarnings("deprecation")
    public void buttonClicks(View v) {
            switch (v.getId()) {
                    case R.id.button1:
                            //post

                            Bundle params= new Bundle();

                            params.putString("name", "User X"); 
                            params.putString("caption", "Rating"); 
                            params.putString("description", "User X Rated"); 
                            params.putString("link", "http://..."); 



                            fb.dialog(MainActivity.this, "feed", params, new Facebook.DialogListener() {

                                    @Override
                                    public void onFacebookError(FacebookError e) {
                                            // TODO Auto-generated method stub

                                    }

                                    @Override
                                    public void onError(DialogError e) {
                                            // TODO Auto-generated method stub

                                    }

                                    @Override
                                    public void onComplete(Bundle values) {
                                            // TODO Auto-generated method stub

                                    }

                                    @Override
                                    public void onCancel() {
                                            // TODO Auto-generated method stub

                                    }
                            });
                            break;
            }
    }
    @SuppressWarnings("deprecation")
    public void onClick(View v) {
            if(fb.isSessionValid()) {

                    try {
                    fb.logout(getApplicationContext());
                    updateButtonImage();
                    //button will close our our session
            }catch(MalformedURLException e) {
                    e.printStackTrace();
            } catch(IOException e) {
                    e.printStackTrace();
            }
    }else{
                    //login into facebook
                    fb.authorize(MainActivity.this, new String[] {"email"}, new Facebook.DialogListener() {

                            @Override
                            public void onFacebookError(FacebookError e) {
                                    // TODO Auto-generated method stub
                                    Toast.makeText(MainActivity.this, "fbError", Toast.LENGTH_SHORT).show();
                            }

                            @Override
                            public void onError(DialogError e) {
                                    // TODO Auto-generated method stub
                                    Toast.makeText(MainActivity.this, "onError", Toast.LENGTH_SHORT).show();
                            }

                            @Override
                            public void onComplete(Bundle values) {
                                    // TODO Auto-generated method stub
                                    Editor editor=sp.edit();
                                    editor.putString("access_token", fb.getAccessToken());
                                    editor.putLong("access_expires", fb.getAccessExpires());
                                    editor.commit();
                                    updateButtonImage();
                            }

                            @Override
                            public void onCancel() {
                                    // TODO Auto-generated method stub
                                    Toast.makeText(MainActivity.this, "onCancel", Toast.LENGTH_SHORT).show();
                            }
                    });

                    }
    }


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
            // Inflate the menu; this adds items to the action bar if it is present.
            getMenuInflater().inflate(R.menu.activity_main, menu);
            return true;
    }

    @SuppressWarnings("deprecation")
    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
            super.onActivityResult(requestCode, resultCode, data);
            fb.authorizeCallback(requestCode, resultCode, data);
    }

    @Override
    public void onComplete(Bundle values) {
            // TODO Auto-generated method stub

    }

    @Override
    public void onFacebookError(FacebookError e) {
            // TODO Auto-generated method stub

    }

    @Override
    public void onError(DialogError e) {
            // TODO Auto-generated method stub

    }

    @Override
    public void onCancel() {
            // TODO Auto-generated method stub

    }

}

LogCat Errors:

12-16 04:56:59.070: E/AndroidRuntime(822): FATAL EXCEPTION: main 12-16 04:56:59.070: E/AndroidRuntime(822): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.sara.facebookappl/com.sara.facebookappl.MainActivity}: android.os.NetworkOnMainThreadException 12-16 04:56:59.070: E/AndroidRuntime(822): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180) 12-16 04:56:59.070: E/AndroidRuntime(822): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230) 12-16 04:56:59.070: E/AndroidRuntime(822): at android.app.ActivityThread.access$600(ActivityThread.java:141) 12-16 04:56:59.070: E/AndroidRuntime(822): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234) 12-16 04:56:59.070: E/AndroidRuntime(822): at android.os.Handler.dispatchMessage(Handler.java:99) 12-16 04:56:59.070: E/AndroidRuntime(822): at android.os.Looper.loop(Looper.java:137) 12-16 04:56:59.070: E/AndroidRuntime(822): at android.app.ActivityThread.main(ActivityThread.java:5039) 12-16 04:56:59.070: E/AndroidRuntime(822): at java.lang.reflect.Method.invokeNative(Native Method) 12-16 04:56:59.070: E/AndroidRuntime(822): at java.lang.reflect.Method.invoke(Method.java:511) 12-16 04:56:59.070: E/AndroidRuntime(822): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793) 12-16 04:56:59.070: E/AndroidRuntime(822): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560) 12-16 04:56:59.070: E/AndroidRuntime(822): at dalvik.system.NativeStart.main(Native Method) 12-16 04:56:59.070: E/AndroidRuntime(822): Caused by: android.os.NetworkOnMainThreadException 12-16 04:56:59.070: E/AndroidRuntime(822): at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1117) 12-16 04:56:59.070: E/AndroidRuntime(822): at java.net.InetAddress.lookupHostByName(InetAddress.java:385) 12-16 04:56:59.070: E/AndroidRuntime(822): at java.net.InetAddress.getAllByNameImpl(InetAddress.java:236) 12-16 04:56:59.070: E/AndroidRuntime(822): at java.net.InetAddress.getAllByName(InetAddress.java:214) 12-16 04:56:59.070: E/AndroidRuntime(822): at libcore.net.http.HttpConnection.(HttpConnection.java:70) 12-16 04:56:59.070: E/AndroidRuntime(822): at libcore.net.http.HttpConnection.(HttpConnection.java:50) 12-16 04:56:59.070: E/AndroidRuntime(822): at libcore.net.http.HttpConnection$Address.connect(HttpConnection.java:340) 12-16 04:56:59.070: E/AndroidRuntime(822): at libcore.net.http.HttpConnectionPool.get(HttpConnectionPool.java:87) 12-16 04:56:59.070: E/AndroidRuntime(822): at libcore.net.http.HttpConnection.connect(HttpConnection.java:128) 12-16 04:56:59.070: E/AndroidRuntime(822): at libcore.net.http.HttpEngine.openSocketConnection(HttpEngine.java:316) 12-16 04:56:59.070: E/AndroidRuntime(822): at libcore.net.http.HttpsURLConnectionImpl$HttpsEngine.makeSslConnection(HttpsURLConnectionImpl.java:461) 12-16 04:56:59.070: E/AndroidRuntime(822): at libcore.net.http.HttpsURLConnectionImpl$HttpsEngine.connect(HttpsURLConnectionImpl.java:433) 12-16 04:56:59.070: E/AndroidRuntime(822): at libcore.net.http.HttpEngine.sendSocketRequest(HttpEngine.java:290) 12-16 04:56:59.070: E/AndroidRuntime(822): at libcore.net.http.HttpEngine.sendRequest(HttpEngine.java:240) 12-16 04:56:59.070: E/AndroidRuntime(822): at libcore.net.http.HttpURLConnectionImpl.getResponse(HttpURLConnectionImpl.java:282) 12-16 04:56:59.070: E/AndroidRuntime(822): at libcore.net.http.HttpURLConnectionImpl.getInputStream(HttpURLConnectionImpl.java:177) 12-16 04:56:59.070: E/AndroidRuntime(822): at libcore.net.http.HttpsURLConnectionImpl.getInputStream(HttpsURLConnectionImpl.java:271) 12-16 04:56:59.070: E/AndroidRuntime(822): at com.facebook.android.Util.openUrl(Util.java:219) 12-16 04:56:59.070: E/AndroidRuntime(822): at com.facebook.android.Facebook.requestImpl(Facebook.java:806) 12-16 04:56:59.070: E/AndroidRuntime(822): at com.facebook.android.Facebook.request(Facebook.java:732) 12-16 04:56:59.070: E/AndroidRuntime(822): at com.sara.facebookappl.MainActivity.updateButtonImage(MainActivity.java:83) 12-16 04:56:59.070: E/AndroidRuntime(822): at com.sara.facebookappl.MainActivity.onCreate(MainActivity.java:63) 12-16 04:56:59.070: E/AndroidRuntime(822): at android.app.Activity.performCreate(Activity.java:5104) 12-16 04:56:59.070: E/AndroidRuntime(822): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080) 12-16 04:56:59.070: E/AndroidRuntime(822): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144) 12-16 04:56:59.070: E/AndroidRuntime(822): ... 11 more 12-16 04:56:59.090: D/dalvikvm(822): GC_CONCURRENT freed 150K, 9% free 2723K/2988K, paused 7ms+58ms, total 239ms