Problem setting up the action bar in Android Studio

public class MainActivity extends ActionBarActivity implements ActionBar.TabListener

import android.content.Intent;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.app.FragmentTransaction;
import android.support.v4.view.ViewPager;
import android.support.v7.app.ActionBar;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;

import com.parse.ParseAnalytics;
import com.parse.ParseUser;


public class MainActivity extends FragmentActivity implements ActionBar.TabListener {


    public static final String TAG = MainActivity.class.getSimpleName();

    /**
     * The {@link android.support.v4.view.PagerAdapter} that will provide
     * fragments for each of the sections. We use a
     * {@link FragmentPagerAdapter} derivative, which will keep every
     * loaded fragment in memory. If this becomes too memory intensive, it
     * may be best to switch to a
     * {@link android.support.v4.app.FragmentStatePagerAdapter}.
     */
    SectionsPagerAdapter mSectionsPagerAdapter;

    /**
     * The {@link ViewPager} that will host the section contents.
     */
    ViewPager mViewPager;

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

        ParseAnalytics.trackAppOpened(getIntent());
        ParseUser currentUser = ParseUser.getCurrentUser();
        if(currentUser == null) {
            navigateToLogin();
        }
        else {
            Log.i(TAG, currentUser.getUsername());

        }
        // Set up the action bar.
        final ActionBar actionBar = getSupportActionBar();  // Error-Cannot resolve method
        actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);

        // Create the adapter that will return a fragment for each of the three
        // primary sections of the activity.
        mSectionsPagerAdapter = new SectionsPagerAdapter(this, getSupportFragmentManager()); // Error- SectionsPageAdapter() in  SectionsPageAdapter cannot be applied to:

        // Set up the ViewPager with the sections adapter.
        mViewPager = (ViewPager) findViewById(R.id.pager);
        mViewPager.setAdapter(mSectionsPagerAdapter);

//Rest of code omitted

public SectionsPagerAdapter(Context context, MainActivity mainActivity, FragmentManager fm) {
        super(fm);
        mContext = context;
    }

public SectionsPagerAdapter(Context context, FragmentManager fm) {
        super(fm);
        mContext = context;
    }