根據條件重定向到某條路線 - Redirecting to a certain route based on condition

問題：

I'm writing a small AngularJS app that has a login view and a main view, configured like so: 我正在編寫一個小的AngularJS應用，該應用具有登錄視圖和主視圖，其配置如下：

$routeProvider
 .when('/main' , {templateUrl: 'partials/main.html',  controller: MainController})
 .when('/login', {templateUrl: 'partials/login.html', controller: LoginController})
 .otherwise({redirectTo: '/login'});

My LoginController checks the user/pass combination and sets a property on the $rootScope reflecting this: 我的LoginController檢查用戶/密碼組合，並在$ rootScope上設置一個屬性，以反映此情況：

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.";
    }
}

Everything works, but if I access http://localhost/#/main I end up bypassing the login screen. 一切正常，但是如果我訪問http://localhost/#/main我最終將繞過登錄屏幕。 I wanted to write something like "whenever the route changes, if $rootScope.loggedUser is null then redirect to /login" 我想寫一些類似的內容，“每當路由更改時，如果$ rootScope.loggedUser爲null，則重定向到/ login”

... ...

... wait. ...等等。 Can I listen to route changes somehow? 我可以聽路線變化嗎？ I'll post this question anyway and keep looking. 無論如何，我都會發布這個問題並繼續尋找。

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解決方案：

參考一： https://en.stackoom.com/question/mQWN
參考二： https://stackoom.com/question/mQWN