Sample ActionBar code

gistfile1.cs

        private void InitializeActionBar()
        {
            ActionBar.NavigationMode = ActionBarNavigationMode.Tabs;

            var firstTab = SetupGraffitiGridTab();
            SetupGraffitiMapTab();

            ActionBar.SelectTab(firstTab);
        }
        
        private ActionBar.Tab SetupGraffitiGridTab()
        {
            _graffittiGridTab = ActionBar.NewTab();
            _graffittiGridTab.SetText(Resources.GetString(Resource.String.tab_text_list));
            _graffittiGridTab.SetIcon(Resource.Drawable.ic_action_graffiti_list);
            _graffittiGridTab.TabSelected += (sender, args) => { DisplayGraffitiGrid(); };

            ActionBar.AddTab(_graffittiGridTab);
            return _graffittiGridTab;
        }

        private void SetupGraffitiMapTab()
        {
            _mapTab = ActionBar.NewTab();
            _mapTab.SetText(Resources.GetString(Resource.String.tab_text_maptab));
            _mapTab.SetIcon(Resource.Drawable.ic_action_graffiti_map);
            _mapTab.TabSelected += (sender, args) => { _viewModel.DisplayAllInMap(this, _locationHelper.LastLocation); };
            ActionBar.AddTab(_mapTab);
        }        

Also need to have this line in OnCreate:

RequestWindowFeature(WindowFeatures.ActionBar);