<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >
    <Button
      android:id="@+id/button"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_gravity="center_horizontal"
      android:text="Button"
      />
  </LinearLayout>
//left_fragment.xml

 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#00ff00"
    android:orientation="vertical" >
    <TextView
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_gravity="center_horizontal"
      android:textSize="20sp"
      android:text="This is right fragment"
      />
  </LinearLayout>

//right_fragment.xml

public class LeftFragment extends Fragment {
  @Override
  public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
  View view = inflater.inflate(R.layout.left_fragment, container, false); return view;
  }
}
public class RightFragment extends Fragment {
  @Override
  public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
  View view = inflater.inflate(R.layout.right_fragment, container, false); return view;
  }
}

 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >
    <fragment
      android:id="@+id/left_fragment"
      android:name="com.example.fragmenttest.LeftFragment"
      android:layout_width="0dp"
      android:layout_height="match_parent"
      android:layout_weight="1" />
    <fragment
      android:id="@+id/right_fragment"
      android:name="com.example.fragmenttest.RightFragment"
      android:layout_width="0dp"
      android:layout_height="match_parent"
      android:layout_weight="1" />
  </LinearLayout>

@Override
    public void onClick(View v) {
      switch (v.getId()) {
      case R.id.button:
        AnotherRightFragment fragment = new AnotherRightFragment();
        FragmentManager fragmentManager = getFragmentManager();
        FragmentTransaction transaction = fragmentManager.
  beginTransaction();
        transaction.replace(R.id.right_layout, fragment);
        transaction.commit();
        break;
      default:
        break;
  } }

 public class MainActivity extends Activity implements OnClickListener {
......
    @Override
    public void onClick(View v) {
      switch (v.getId()) {
      case R.id.button:
        AnotherRightFragment fragment = new AnotherRightFragment();
        FragmentManager fragmentManager = getFragmentManager();
        FragmentTransaction transaction = fragmentManager.
  beginTransaction();
        transaction.replace(R.id.right_layout, fragment);
        transaction.addToBackStack(null);
        transaction.commit();
        break;
      default:
  break; }
  }
}

  RightFragment rightFragment = (RightFragment) getFragmentManager()
      .findFragmentById(R.id.right_fragment);

  MainActivity activity = (MainActivity) getActivity();