ionicNavState.js

directive('tab', ['NavStateDelegate', '$scope', function(NavStateDelegate, $scope) {
  return {
    //
    link: function($scope, $element, $attr) {
      // Indicate to this delegate we want to control a nav bar
      NavStateDelegate.enable(scope);
    }
  }
}])

// Service
factory('NavStateDelegate', function() {
  return {
    register: function($scope) {
            // Should we hide a back button when this tab is shown
      $scope.hideBackButton = $scope.$eval($scope.hideBackButton);

      $scope.hideNavBar = $scope.$eval($scope.hideNavBar);

      navCtrl.navBar.isVisible = !$scope.hideNavBar;

      if($scope.hideBackButton === true) {
        $scope.$emit('navRouter.hideBackButton');
      } else {
        $scope.$emit('navRouter.showBackButton');
      }


      // watch for changes in the left buttons
      $scope.$watch('leftButtons', function(value) {
        $scope.$emit('navRouter.leftButtonsChanged', $scope.leftButtons);
      });

      $scope.$watch('rightButtons', function(val) {
        $scope.$emit('navRouter.rightButtonsChanged', $scope.rightButtons);
      });


      // watch for changes in the title
      $scope.$watch('title', function(value) {
        $scope.$emit('navRouter.titleChanged', {
          title: value,
          animate: $scope.animate
        });
      });

    }
  }
})