Angular JS-如何僅在完成函數后才執行代碼

Question

我在app.run有一個函數AuthService.saveSession()

我在$stateChangeStart函數中調用AuthService.isLoggedIn()時說未定義，因為兩個函數同時被調用。

AuthService.saveSession()完成后，如何使我的代碼執行$stateChangeStart 。

希望我能很清楚地解釋任何疑問，請發表評論。

更新資料

app.run(function($rootScope, $location, $state, $http, $q, AuthService){

AuthService.saveSession();

$rootScope.$on('$stateChangeStart', function(event, toState, toParams, fromState,fromParams){
alert(AuthService.isLoggedIn()); // It says undefined.

});

Answer 1

您可以使用$ q並返回一個promise：

例如：

  function saveSession(){
      var deferred = $q.defer();
      //insert logic and async calls here
      //after everything is done, do this
      deferred.resolve(data); //where data is the data you want to get

      return deferred.promise;
  }

並這樣稱呼：

  var promise = saveSession();
  promise.then(function(data){
      $rootScope.$on('$stateChangeStart', function(event, toState, toParams, fromState,fromParams){
        alert(AuthService.isLoggedIn());
      });
  });

Answer 2

在使用工廠時使用此方法

 //factory for AuthService service , put $q in dependency in factory

 saveSession:function(){
    var deferred = $q.defer();
    //insert logic and async calls here
    //after everything is done, do this
    deferred.resolve(data); //where data is the data you want to get

    return deferred.promise;
}
   AuthService.saveSession().then(function(status){
     //do action here after getting promise
     $rootScope.$on('$stateChangeStart', function(event, toState, toParams, fromState,fromParams){

  //do what ever you want
  });
  })