Popup Window with FragmentActivity

Question

I have my popup windows with "extends activity". I searched and I knew that I cannot extent twice.

So, How can I put the content in a pop up with the FragmentActivity?

Edit:

this is the main activity

public class Kulintang extends AppCompatActivity implements OnMenuItemClickListener {

    SoundPool mySound;

    int aID, bID, cID, dID, eID, fID, gID, hID;
    private Button brecord;
    private String FILE;//File path
    private MediaRecorder record;
    ......

this is the class i want to pop up when i tap the button

public class play extends FragmentActivity implements ActionBar.TabListener {


    ActionBar actionBar;
    ViewPager viewPager;


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

        viewPager = (ViewPager) findViewById(R.id.pager);
        viewPager.setAdapter(new MyAdapter(getSupportFragmentManager()));
        viewPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
            @Override
            public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {

            }

            @Override
            public void onPageSelected(int position) {
                actionBar.setSelectedNavigationItem(position);
            }

            @Override
            public void onPageScrollStateChanged(int state) {

            }
        });
        actionBar = getActionBar();
        actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);


        ActionBar.Tab tab1=actionBar.newTab();
        tab1.setText("Recorded");
        tab1.setTabListener(this);

        ActionBar.Tab tab2=actionBar.newTab();
        tab2.setText("Songs");
        tab2.setTabListener(this);

        actionBar.addTab(tab1);
        actionBar.addTab(tab2);

    }