MainActivity_AddTab.cs

void AddTab(string tabText, Fragment view)
{
    var tab = this.ActionBar.NewTab();
    tab.SetText(tabText);

    tab.TabSelected += delegate (object sender, ActionBar.TabEventArgs e)
    {
        var fragment = this.FragmentManager.FindFragmentById(Resource.Id.tabFragmentsContainer);
        if (fragment != null)
            e.FragmentTransaction.Remove(fragment);
        e.FragmentTransaction.Add(Resource.Id.tabFragmentsContainer, view);
    };
    tab.TabUnselected += delegate (object sender, ActionBar.TabEventArgs e) {
        e.FragmentTransaction.Remove(view);
    };

    this.ActionBar.AddTab(tab);
}