AngularJS - refresh view after http request, $root

问题:

Hey guys so I am simply trying to load data when my app starts. However, the view loads faster than the http request(of course). I want to refresh my view once my data has been properly loaded because that data defines my view.

I've tried $rootScope.apply from inside the factory where I do my http request, and I also tried directly doing the http request in my controller again with $scope.apply, and neither one worked as they both gave me "$digest already in progress"

Any idea how can I set up my code to make my views refresh on data load? I will be having several different http requests and I would like to know how to set them up properly! I would really appreciate any input!

Here is some of the code I am working with.

app.factory('HttpRequestFactory', function($http, $q) {
  var HttpRequestFactory = {
    async: function(url, params) {
      var deferred = $q.defer();
      $http({
        url: url,
        method: post,
        params: params
      })
        .success(function(data, status, headers, config) {
          deferred.resolve(data);
        })
        .error(function(data, status, headers, config) {
          deferred.reject("An error occurred");
        });
      return deferred.promise;
    }
  };
  return HttpRequestFactory;
});

Factory

function initializeAll(){   
    HttpRequestFactory.async('../api', {action: 'getall'}).then(function(data) {
            //$rootScope.$apply(function () {
                allData = data;
            //});
        angular.forEach(allData, function(value, index){
            console.log('Voala!');
        });
    });
}

Controller calling the factory's function initializeAll()

app.controller("MainController", ["$scope", "$rootScope","MyFactory", 
    function($scope, $rootScope, MyFactory){
        MyFactory.initializeAll();

    }
]);

回答1:

Oh my !

You got the f** matter with AngularJS !

In fact you have to do a "safeApply" like that for example :

$rootScope.safeApply = function(fn) {
    var phase = this.$root.$$phase;
    if(phase == '$apply' || phase == '$digest') {
        if(fn && (typeof(fn) === 'function')) {
            fn();
        }
    } else {
        this.$apply(fn);
    }
};

In AngularJS you can only have one $apply or $digest loop at the same time.

For details on these loops look at the docs : http://docs.angularjs.org/guide/concepts

It will explain what is the $apply loop and you'll understand a lot of things about the two-way-data-binding in AngularJS

Hope it helps.

回答2:

Don't use $apply: use $watch.

Calling $apply is (almost) always the wrong thing to do. The only time you should ever be calling it is if you've triggered a change outside of an 'angular' method; here, since the trigger occurs in an angular $http request, you can't call $apply because it's already being done at that moment by the $http block. Instead, what you want to do is $watch.

Official Doc for $scope.$watch() here

This will let you watch an object and update whenever it changes. I assume that your view is based on allData and you want it to update immediately; if you're using an ng method, then the watch is automatically setup for you and no more work should be needed. If you're using allData yourself inside a controller, you can write the watch in that controller like this:

$scope.$watch(function thingYouWantToWatch(){
         return <accessor call to allData here>;
      }, 
      function whatToDoOnChange(newValue, oldValue){
          $scope.myCoolThing = newValue; //this is the newValue of allData, or whatever you're watching.
      }
);