Android emulator unfortunately HelloFacebookSample has stopped

I am a new to android APP. I download facebook sdk for android (https://developers.facebook.com/android/). Everything is fine except running in emulator. Everything samples in SDK cannot rightly be ran and a error of "unfortualtely, XXX has stopped" is popped. Could someone meet similar problems? Thanks. Here is the log in LogCat:

06-02 16:33:41.165: D/dalvikvm(536): Not late-enabling CheckJNI (already on)
06-02 16:33:41.425: I/dalvikvm(536): Turning on JNI app bug workarounds for target SDK version 8...
06-02 16:33:41.715: W/dalvikvm(536): Unable to resolve superclass of Lcom/facebook/samples/hellofacebook/HelloFacebookSampleActivity; (59)
06-02 16:33:41.715: W/dalvikvm(536): Link of class 'Lcom/facebook/samples/hellofacebook/HelloFacebookSampleActivity;' failed
06-02 16:33:41.715: D/AndroidRuntime(536): Shutting down VM
06-02 16:33:41.715: W/dalvikvm(536): threadid=1: thread exiting with uncaught exception (group=0x409c01f8)
06-02 16:33:41.755: E/AndroidRuntime(536): FATAL EXCEPTION: main
06-02 16:33:41.755: E/AndroidRuntime(536): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.facebook.samples.hellofacebook/com.facebook.samples.hellofacebook.HelloFacebookSampleActivity}: java.lang.ClassNotFoundException: com.facebook.samples.hellofacebook.HelloFacebookSampleActivity
06-02 16:33:41.755: E/AndroidRuntime(536):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1880)
06-02 16:33:41.755: E/AndroidRuntime(536):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1981)
06-02 16:33:41.755: E/AndroidRuntime(536):  at android.app.ActivityThread.access$600(ActivityThread.java:123)
06-02 16:33:41.755: E/AndroidRuntime(536):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1147)
06-02 16:33:41.755: E/AndroidRuntime(536):  at android.os.Handler.dispatchMessage(Handler.java:99)
06-02 16:33:41.755: E/AndroidRuntime(536):  at android.os.Looper.loop(Looper.java:137)
06-02 16:33:41.755: E/AndroidRuntime(536):  at android.app.ActivityThread.main(ActivityThread.java:4424)
06-02 16:33:41.755: E/AndroidRuntime(536):  at java.lang.reflect.Method.invokeNative(Native Method)
06-02 16:33:41.755: E/AndroidRuntime(536):  at java.lang.reflect.Method.invoke(Method.java:511)
06-02 16:33:41.755: E/AndroidRuntime(536):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
06-02 16:33:41.755: E/AndroidRuntime(536):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
06-02 16:33:41.755: E/AndroidRuntime(536):  at dalvik.system.NativeStart.main(Native Method)
06-02 16:33:41.755: E/AndroidRuntime(536): Caused by: java.lang.ClassNotFoundException: com.facebook.samples.hellofacebook.HelloFacebookSampleActivity
06-02 16:33:41.755: E/AndroidRuntime(536):  at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:61)
06-02 16:33:41.755: E/AndroidRuntime(536):  at java.lang.ClassLoader.loadClass(ClassLoader.java:501)
06-02 16:33:41.755: E/AndroidRuntime(536):  at java.lang.ClassLoader.loadClass(ClassLoader.java:461)
06-02 16:33:41.755: E/AndroidRuntime(536):  at android.app.Instrumentation.newActivity(Instrumentation.java:1023)
06-02 16:33:41.755: E/AndroidRuntime(536):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1871)
06-02 16:33:41.755: E/AndroidRuntime(536):  ... 11 more
06-02 16:33:42.365: I/dalvikvm(536): threadid=3: reacting to signal 3
06-02 16:33:42.375: I/dalvikvm(536): Wrote stack traces to '/data/anr/traces.txt'
06-02 16:33:42.875: I/dalvikvm(536): threadid=3: reacting to signal 3
06-02 16:33:42.885: I/dalvikvm(536): Wrote stack traces to '/data/anr/traces.txt' 

Here is the manifest:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
          package="com.facebook.samples.hellofacebook"
          android:versionCode="1"
          android:versionName="1.0">
    <uses-sdk android:minSdkVersion="8"/>
    <uses-permission android:name="android.permission.INTERNET"/>
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
    <application android:label="@string/app_name"
                 android:icon="@drawable/icon"
                 android:theme="@android:style/Theme.NoTitleBar"
            >
        <activity android:name=".HelloFacebookSampleActivity"
                  android:label="@string/app_name"
                  android:windowSoftInputMode="adjustResize">
            <intent-filter>
                <action android:name="android.intent.action.MAIN"/>
                <category android:name="android.intent.category.LAUNCHER"/>
            </intent-filter>
        </activity>
        <activity android:name="com.facebook.LoginActivity"
                  android:theme="@android:style/Theme.Translucent.NoTitleBar"
                  android:label="@string/app_name" />
        <meta-data android:name="com.facebook.sdk.ApplicationId" android:value="@string/app_id"/>
    </application>
</manifest>

Here is the source code:

/**
 * Copyright 2012 Facebook
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.facebook.samples.hellofacebook;

import android.app.AlertDialog;
import android.content.Intent;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.location.Location;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentManager;
import android.text.TextUtils;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.TextView;
import com.facebook.*;
import com.facebook.model.GraphObject;
import com.facebook.model.GraphPlace;
import com.facebook.model.GraphUser;
import com.facebook.widget.*;

import java.util.*;

public class HelloFacebookSampleActivity extends FragmentActivity {

    private static final List<String> PERMISSIONS = Arrays.asList("publish_actions");
    private static final Location SEATTLE_LOCATION = new Location("") {
        {
            setLatitude(47.6097);
            setLongitude(-122.3331);
        }
    };

    private final String PENDING_ACTION_BUNDLE_KEY = "com.facebook.samples.hellofacebook:PendingAction";

    private Button postStatusUpdateButton;
    private Button postPhotoButton;
    private Button pickFriendsButton;
    private Button pickPlaceButton;
    private LoginButton loginButton;
    private ProfilePictureView profilePictureView;
    private TextView greeting;
    private PendingAction pendingAction = PendingAction.NONE;
    private ViewGroup controlsContainer;
    private GraphUser user;

    private enum PendingAction {
        NONE,
        POST_PHOTO,
        POST_STATUS_UPDATE
    }
    private UiLifecycleHelper uiHelper;

    private Session.StatusCallback callback = new Session.StatusCallback() {
        @Override
        public void call(Session session, SessionState state, Exception exception) {
            onSessionStateChange(session, state, exception);
        }
    };

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        uiHelper = new UiLifecycleHelper(this, callback);
        uiHelper.onCreate(savedInstanceState);

        if (savedInstanceState != null) {
            String name = savedInstanceState.getString(PENDING_ACTION_BUNDLE_KEY);
            pendingAction = PendingAction.valueOf(name);
        }

        setContentView(R.layout.main);

        loginButton = (LoginButton) findViewById(R.id.login_button);
        loginButton.setUserInfoChangedCallback(new LoginButton.UserInfoChangedCallback() {
            @Override
            public void onUserInfoFetched(GraphUser user) {
                HelloFacebookSampleActivity.this.user = user;
                updateUI();
                // It's possible that we were waiting for this.user to be populated in order to post a
                // status update.
                handlePendingAction();
            }
        });

        profilePictureView = (ProfilePictureView) findViewById(R.id.profilePicture);
        greeting = (TextView) findViewById(R.id.greeting);

        postStatusUpdateButton = (Button) findViewById(R.id.postStatusUpdateButton);
        postStatusUpdateButton.setOnClickListener(new View.OnClickListener() {
            public void onClick(View view) {
                onClickPostStatusUpdate();
            }
        });

        postPhotoButton = (Button) findViewById(R.id.postPhotoButton);
        postPhotoButton.setOnClickListener(new View.OnClickListener() {
            public void onClick(View view) {
                onClickPostPhoto();
            }
        });

        pickFriendsButton = (Button) findViewById(R.id.pickFriendsButton);
        pickFriendsButton.setOnClickListener(new View.OnClickListener() {
            public void onClick(View view) {
                onClickPickFriends();
            }
        });

        pickPlaceButton = (Button) findViewById(R.id.pickPlaceButton);
        pickPlaceButton.setOnClickListener(new View.OnClickListener() {
            public void onClick(View view) {
                onClickPickPlace();
            }
        });

        controlsContainer = (ViewGroup) findViewById(R.id.main_ui_container);

        final FragmentManager fm = getSupportFragmentManager();
        Fragment fragment = fm.findFragmentById(R.id.fragment_container);
        if (fragment != null) {
            // If we're being re-created and have a fragment, we need to a) hide the main UI controls and
            // b) hook up its listeners again.
            controlsContainer.setVisibility(View.GONE);
            if (fragment instanceof FriendPickerFragment) {
                setFriendPickerListeners((FriendPickerFragment) fragment);
            } else if (fragment instanceof PlacePickerFragment) {
                setPlacePickerListeners((PlacePickerFragment) fragment);
            }
        }

        // Listen for changes in the back stack so we know if a fragment got popped off because the user
        // clicked the back button.
        fm.addOnBackStackChangedListener(new FragmentManager.OnBackStackChangedListener() {
            @Override
            public void onBackStackChanged() {
                if (fm.getBackStackEntryCount() == 0) {
                    // We need to re-show our UI.
                    controlsContainer.setVisibility(View.VISIBLE);
                }
            }
        });
    }

    @Override
    protected void onResume() {
        super.onResume();
        uiHelper.onResume();

        updateUI();
    }

    @Override
    protected void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        uiHelper.onSaveInstanceState(outState);

        outState.putString(PENDING_ACTION_BUNDLE_KEY, pendingAction.name());
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        uiHelper.onActivityResult(requestCode, resultCode, data);
    }

    @Override
    public void onPause() {
        super.onPause();
        uiHelper.onPause();
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        uiHelper.onDestroy();
    }

    private void onSessionStateChange(Session session, SessionState state, Exception exception) {
        if (pendingAction != PendingAction.NONE &&
                (exception instanceof FacebookOperationCanceledException ||
                exception instanceof FacebookAuthorizationException)) {
                new AlertDialog.Builder(HelloFacebookSampleActivity.this)
                    .setTitle(R.string.cancelled)
                    .setMessage(R.string.permission_not_granted)
                    .setPositiveButton(R.string.ok, null)
                    .show();
            pendingAction = PendingAction.NONE;
        } else if (state == SessionState.OPENED_TOKEN_UPDATED) {
            handlePendingAction();
        }
        updateUI();
    }

    private void updateUI() {
        Session session = Session.getActiveSession();
        boolean enableButtons = (session != null && session.isOpened());

        postStatusUpdateButton.setEnabled(enableButtons);
        postPhotoButton.setEnabled(enableButtons);
        pickFriendsButton.setEnabled(enableButtons);
        pickPlaceButton.setEnabled(enableButtons);

        if (enableButtons && user != null) {
            profilePictureView.setProfileId(user.getId());
            greeting.setText(getString(R.string.hello_user, user.getFirstName()));
        } else {
            profilePictureView.setProfileId(null);
            greeting.setText(null);
        }
    }

    @SuppressWarnings("incomplete-switch")
    private void handlePendingAction() {
        PendingAction previouslyPendingAction = pendingAction;
        // These actions may re-set pendingAction if they are still pending, but we assume they
        // will succeed.
        pendingAction = PendingAction.NONE;

        switch (previouslyPendingAction) {
            case POST_PHOTO:
                postPhoto();
                break;
            case POST_STATUS_UPDATE:
                postStatusUpdate();
                break;
        }
    }

    private interface GraphObjectWithId extends GraphObject {
        String getId();
    }

    private void showPublishResult(String message, GraphObject result, FacebookRequestError error) {
        String title = null;
        String alertMessage = null;
        if (error == null) {
            title = getString(R.string.success);
            String id = result.cast(GraphObjectWithId.class).getId();
            alertMessage = getString(R.string.successfully_posted_post, message, id);
        } else {
            title = getString(R.string.error);
            alertMessage = error.getErrorMessage();
        }

        new AlertDialog.Builder(this)
                .setTitle(title)
                .setMessage(alertMessage)
                .setPositiveButton(R.string.ok, null)
                .show();
    }

    private void onClickPostStatusUpdate() {
        performPublish(PendingAction.POST_STATUS_UPDATE);
    }

    private void postStatusUpdate() {
        if (user != null && hasPublishPermission()) {
            final String message = getString(R.string.status_update, user.getFirstName(), (new Date().toString()));
            Request request = Request
                    .newStatusUpdateRequest(Session.getActiveSession(), message, new Request.Callback() {
                        @Override
                        public void onCompleted(Response response) {
                            showPublishResult(message, response.getGraphObject(), response.getError());
                        }
                    });
            request.executeAsync();
        } else {
            pendingAction = PendingAction.POST_STATUS_UPDATE;
        }
    }

    private void onClickPostPhoto() {
        performPublish(PendingAction.POST_PHOTO);
    }

    private void postPhoto() {
        if (hasPublishPermission()) {
            Bitmap image = BitmapFactory.decodeResource(this.getResources(), R.drawable.icon);
            Request request = Request.newUploadPhotoRequest(Session.getActiveSession(), image, new Request.Callback() {
                @Override
                public void onCompleted(Response response) {
                    showPublishResult(getString(R.string.photo_post), response.getGraphObject(), response.getError());
                }
            });
            request.executeAsync();
        } else {
            pendingAction = PendingAction.POST_PHOTO;
        }
    }

    private void showPickerFragment(PickerFragment<?> fragment) {
        fragment.setOnErrorListener(new PickerFragment.OnErrorListener() {
            @Override
            public void onError(PickerFragment<?> pickerFragment, FacebookException error) {
                showAlert(getString(R.string.error), error.getMessage());
            }
        });

        FragmentManager fm = getSupportFragmentManager();
        fm.beginTransaction()
                .replace(R.id.fragment_container, fragment)
                .addToBackStack(null)
                .commit();

        controlsContainer.setVisibility(View.GONE);

        // We want the fragment fully created so we can use it immediately.
        fm.executePendingTransactions();

        fragment.loadData(false);
    }

    private void onClickPickFriends() {
        final FriendPickerFragment fragment = new FriendPickerFragment();

        setFriendPickerListeners(fragment);

        showPickerFragment(fragment);
    }

    private void setFriendPickerListeners(final FriendPickerFragment fragment) {
        fragment.setOnDoneButtonClickedListener(new FriendPickerFragment.OnDoneButtonClickedListener() {
            @Override
            public void onDoneButtonClicked(PickerFragment<?> pickerFragment) {
                onFriendPickerDone(fragment);
            }
        });
    }

    private void onFriendPickerDone(FriendPickerFragment fragment) {
        FragmentManager fm = getSupportFragmentManager();
        fm.popBackStack();

        String results = "";

        Collection<GraphUser> selection = fragment.getSelection();
        if (selection != null && selection.size() > 0) {
            ArrayList<String> names = new ArrayList<String>();
            for (GraphUser user : selection) {
                names.add(user.getName());
            }
            results = TextUtils.join(", ", names);
        } else {
            results = getString(R.string.no_friends_selected);
        }

        showAlert(getString(R.string.you_picked), results);
    }

    private void onPlacePickerDone(PlacePickerFragment fragment) {
        FragmentManager fm = getSupportFragmentManager();
        fm.popBackStack();

        String result = "";

        GraphPlace selection = fragment.getSelection();
        if (selection != null) {
            result = selection.getName();
        } else {
            result = getString(R.string.no_place_selected);
        }

        showAlert(getString(R.string.you_picked), result);
    }

    private void onClickPickPlace() {
        final PlacePickerFragment fragment = new PlacePickerFragment();
        fragment.setLocation(SEATTLE_LOCATION);
        fragment.setTitleText(getString(R.string.pick_seattle_place));

        setPlacePickerListeners(fragment);

        showPickerFragment(fragment);
    }

    private void setPlacePickerListeners(final PlacePickerFragment fragment) {
        fragment.setOnDoneButtonClickedListener(new PlacePickerFragment.OnDoneButtonClickedListener() {
            @Override
            public void onDoneButtonClicked(PickerFragment<?> pickerFragment) {
                onPlacePickerDone(fragment);
            }
        });
        fragment.setOnSelectionChangedListener(new PlacePickerFragment.OnSelectionChangedListener() {
            @Override
            public void onSelectionChanged(PickerFragment<?> pickerFragment) {
                if (fragment.getSelection() != null) {
                    onPlacePickerDone(fragment);
                }
            }
        });
    }

    private void showAlert(String title, String message) {
        new AlertDialog.Builder(this)
                .setTitle(title)
                .setMessage(message)
                .setPositiveButton(R.string.ok, null)
                .show();
    }

    private boolean hasPublishPermission() {
        Session session = Session.getActiveSession();
        return session != null && session.getPermissions().contains("publish_actions");
    }

    private void performPublish(PendingAction action) {
        Session session = Session.getActiveSession();
        if (session != null) {
            pendingAction = action;
            if (hasPublishPermission()) {
                // We can do the action right away.
                handlePendingAction();
            } else {
                // We need to get new permissions, then complete the action when we get called back.
                session.requestNewPublishPermissions(new Session.NewPermissionsRequest(this, PERMISSIONS));
            }
        }
    }
}