Android สอบถามการทำปุ่มย้อนกลับบน ActionBar จากหน้า Activity กลับไปหน้า Fragment

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()) {
    // Respond to the action bar's Up/Home button
    case android.R.id.home:
        Intent upIntent = NavUtils.getParentActivityIntent(this);
        if (NavUtils.shouldUpRecreateTask(this, upIntent)) {
            // This activity is NOT part of this app's task, so create a new task
            // when navigating up, with a synthesized back stack.
            TaskStackBuilder.create(this)
                    // Add all of this activity's parents to the back stack
                    .addNextIntentWithParentStack(upIntent)
                    // Navigate up to the closest parent
                    .startActivities();
        } else {
            // This activity is part of this app's task, so simply
            // navigate up to the logical parent activity.
            NavUtils.navigateUpTo(this, upIntent);
        }
        return true;
    }
    return super.onOptionsItemSelected(item);
}

import android.content.Intent;
import android.os.Bundle;
import android.support.v4.app.NavUtils;
import android.support.v4.app.TaskStackBuilder;
import android.support.v7.app.ActionBar;
import android.support.v7.app.ActionBarActivity;
import android.view.MenuItem;
import android.widget.ArrayAdapter;
import android.widget.ListView;

public class Gpp extends ActionBarActivity {

    private ListView gpp;
    private String[] list = {"ผลิตภัณฑ์มวลรวมจังหวัดสระแก้ว",
            "ผลิตภัณฑ์มวลรวมรายจังหวัด",
            "ผลิตภัณฑ์มวลรวมรายภูมิภาค",
            "ผลิตภัณฑ์มวลรวมกลุ่มเบญจบูรพาสุวรรณภูมิ",
            "ผลิตภัณฑ์มวลรวมในประเทศ",
            "ผลิตภัณฑ์มวลรวมในประเทศ (กำหนดตามความต้องการของผู้ใช้)"};

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

        /*ActionBar actionBar = getSupportActionBar();
        actionBar.setDisplayHomeAsUpEnabled(true);*/

        gpp = (ListView) findViewById(R.id.listView);
        ArrayAdapter<String> objAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, list);
        gpp.setAdapter(objAdapter);
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) {
            // Respond to the action bar's Up/Home button
            case android.R.id.home:
                Intent upIntent = NavUtils.getParentActivityIntent(this);
                if (NavUtils.shouldUpRecreateTask(this, upIntent)) {
                    // This activity is NOT part of this app's task, so create a new task
                    // when navigating up, with a synthesized back stack.
                    TaskStackBuilder.create(this)
                            // Add all of this activity's parents to the back stack
                            .addNextIntentWithParentStack(upIntent)
                                    // Navigate up to the closest parent
                            .startActivities();
                } else {
                    // This activity is part of this app's task, so simply
                    // navigate up to the logical parent activity.
                    NavUtils.navigateUpTo(this, upIntent);
                }
                return true;
        }
        return super.onOptionsItemSelected(item);
    }

}