Halaman login aplikasi tidak ditampilkan - Android Facebook

Saya mencoba membuka layar login aplikasi di Facebook. Saat aktivitas dimulai, layar menampilkan halaman pemuatan facebook lalu menghilang dan halaman tersebut disetel ke R.layout.main.

Saya pasti melewatkan maksudnya di sini, tetapi bagaimana cara saya masuk ke halaman login aplikasi agar pengguna dapat login.

Saya telah mengikuti tutorial berdasarkan https://developers.facebook.com/docs/mobile/android/build/#enablesso

FYI - Saya telah menghapus APP_ID

package com.example.facebook;

import android.app.Activity;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;

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


public class MyGreatActivity extends Activity {

    Facebook facebook = new Facebook("APP_ID");
    private SharedPreferences mPrefs;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        /*
         * Get existing access_token if any
         */
        mPrefs = getPreferences(MODE_PRIVATE);
        String access_token = mPrefs.getString("access_token", null);
        long expires = mPrefs.getLong("access_expires", 0);
        if(access_token != null) {
            facebook.setAccessToken(access_token);
        }
        if(expires != 0) {
            facebook.setAccessExpires(expires);
        }

        /*
         * Only call authorize if the access_token has expired.
         */
        if(!facebook.isSessionValid()) {

            facebook.authorize(this, new String[] {}, new DialogListener() {
                @Override
                public void onComplete(Bundle values) {
                    SharedPreferences.Editor editor = mPrefs.edit();
                    editor.putString("access_token", facebook.getAccessToken());
                    editor.putLong("access_expires", facebook.getAccessExpires());
                    editor.commit();
                }

                @Override
                public void onFacebookError(FacebookError error) {}

                @Override
                public void onError(DialogError e) {}

                @Override
                public void onCancel() {}
            });
        }
    }

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

        facebook.authorizeCallback(requestCode, resultCode, data);
    }
}

Terima kasih atas bantuan Anda.