error in mainActivity

[hiashutoshsingh]

package com.sunshine.www.sunshine;

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v7.app.ActionBarActivity;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;

import com.sunshine.www.sunshine.R;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

public class MainActivity extends ActionBarActivity { //error in this line ActionBatActivity has a stroke

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    if (savedInstanceState == null) {
        getSupportFragmentManager().beginTransaction()
                .add(R.id.container, new PlaceholderFragment()) // conatiner  is assigned to what?
                .commit();
    }
}

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

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();

    //noinspection SimplifiableIfStatement
    if (id == R.id.action_settings) { //  action_settings is assigned to what?
        return true;
    }

    return super.onOptionsItemSelected(item);
}

/**
 * A placeholder fragment containing a simple view.
 */
public static class PlaceholderFragment extends Fragment {

    ArrayAdapter<String> mForecastAdapter;

    public PlaceholderFragment() {
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {

        // Create some dummy data for the ListView.  Here's a sample weekly forecast
        String[] data = {
                "Mon 6/23 - Sunny - 31/17",
                "Tue 6/24 - Foggy - 21/8",
                "Wed 6/25 - Cloudy - 22/17",
                "Thurs 6/26 - Rainy - 18/11",
                "Fri 6/27 - Foggy - 21/10",
                "Sat 6/28 - TRAPPED IN WEATHERSTATION - 23/18",
                "Sun 6/29 - Sunny - 20/7"
        };
        List<String> weekForecast = new ArrayList<String>(Arrays.asList(data));


        // Now that we have some dummy forecast data, create an ArrayAdapter.
        // The ArrayAdapter will take data from a source (like our dummy forecast) and
        // use it to populate the ListView it's attached to.
        mForecastAdapter =
                new ArrayAdapter<String>(
                        getActivity(), // The current context (this activity)
                        R.layout.list_item_forecast, // The name of the layout ID.
                        R.id.list_item_forecast_textview, // The ID of the textview to populate.
                        weekForecast);

        View rootView = inflater.inflate(R.layout.fragment_main, container, false);
        return rootView;
    }
}

}