Can't change a fragment in ViewPager
<p>I'm trying to change a fragment inside a ViewPager:</p>

<pre><code>public void change() {
    android.support.v4.app.FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
    ft.replace(R.id.pager, mapa);
    ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE);
    ft.commit();
    mSectionsPagerAdapter.notifyDataSetChanged();
}
</code></pre>

<p>R.id.pager is my ViewPager id.
mapa is a inflated fragment.
If I call change(), the fragment I want to replace will disappear but the new fragment will not be load.</p>
