refresh listview with baseadapter on fragment

I have a listview (BaseAdapter) (I fill it with SQLite) on a fragment, this fragment is on PageViewer with Swipe. Also, There is a button on ActionBar, when I click on the button, this download the data (external SQLServer) and I sync with SQLite.

app

How can when I click on the button the listview refresh/update visually it on the activity?