问如何根据情况重定向？

$routeProvide

 .when('/main' , {templateUrl: 'partials/main.html',  controller: MainController})

 .when('/login', {templateUrl: 'partials/login.html', controller: LoginController})

 .otherwise({redirectTo: '/login'});

function LoginController($scope, $location, $rootScope) {

 $scope.attemptLogin = function() {

   if ( $scope.username == $scope.password ) { // test

        $rootScope.loggedUser = $scope.username;

        $location.path( "/main" );

    } else {

        $scope.loginError = "Invalid user/pass.";

    }

}