javascript - angular中使用了broadcast和on，為什麼on裡面的代碼不是每次都成功運行？

var app = angular.module('gzmu', ["ngRoute",'chart.js']);app.run(function ($rootScope, $http) {    $http({        method: 'GET',        url: 'datacon/user_info.php',    }).success(function (response) {            $rootScope.userinfo = response[0];        console.log($rootScope.userinfo)        $rootScope.$broadcast("userinfo", response[0]);    })});app.controller('data', function ($scope, $http, $rootScope) {    $scope.usernamea='';    $scope.$on("userinfo",        function (event, msg) {            console.log(msg);            if(msg){                $scope.usernamea = msg.user;                console.log($scope.usernamea)                alert($scope.usernamea)            }            else{                alert(msg)            }        });}）;

如題，on裡面的代碼為什麼不會每載入一次頁面都運行一次？

回複內容：

var app = angular.module('gzmu', ["ngRoute",'chart.js']);app.run(function ($rootScope, $http) {    $http({        method: 'GET',        url: 'datacon/user_info.php',    }).success(function (response) {            $rootScope.userinfo = response[0];        console.log($rootScope.userinfo)        $rootScope.$broadcast("userinfo", response[0]);    })});app.controller('data', function ($scope, $http, $rootScope) {    $scope.usernamea='';    $scope.$on("userinfo",        function (event, msg) {            console.log(msg);            if(msg){                $scope.usernamea = msg.user;                console.log($scope.usernamea)                alert($scope.usernamea)            }            else{                alert(msg)            }        });}）;

如題，on裡面的代碼為什麼不會每載入一次頁面都運行一次？

主要原因是在app的run中broadcast其實是一個非同步作業，如果說data這個Controller在run中的請求成功並且broadcast之前建立，就會成功調用，否則它接收不到root廣播過來的資訊

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