code: function _updateView(event) {
          var index = this.tabBar.getSelectedItemIndex();
          this.animationController.halt();
          if (index >= 0) {
              this.animationController.show(this._items[index].view);
          }
          else {
              this.animationController.hide();
          }
      }
docs: Updates the view-container with the selected view.