ACTIVITY中add Fragment

public class NearByDetailActivity extends FragmentActivity   implements OnClickListener {       

// Create new fragment and transaction
        Fragment newFragment = new CouponsFragment();
        FragmentManager fragmentManager = getSupportFragmentManager();
        // Replace whatever is in the fragment_container view with this fragment,
        // and add the transaction to the back stack
        FragmentTransaction transaction = fragmentManager.beginTransaction();
        transaction.replace(R.id.displayMessageListContainer, newFragment);
        transaction.addToBackStack(null);
        // Commit the transaction
        transaction.commit();


import android.support.v4.app.DialogFragment;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;