AngularJS承诺，$ Q，推迟 [英] AngularJS Promises, $q, defer

问题描述

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第一个答案是优雅的，但是，在这个问题说了几次，计算器上的另一个问题，这个问题是服务和控制器上运行自己的事情的数据实际上到达之前。

The first answer is the elegant one, but, as stated a few times in this question and another questions on stackoverflow, the problem is that the service and the controller run their thing before the data actually arrives.

（第一个答案最新的留言：）

(Last comment on the first answer:)

是的，问题是，API调用完成服务奔跑之后
  并返回一切控制器，看这里
  screencast.com/t/uRKMZ1IgGpb7 ......这是我的基本问题，我怎么可能
  等待所有部件的数据到达？

Yes, the problem is that the API calls finish AFTER the service runs and returns everything to the controller, see here screencast.com/t/uRKMZ1IgGpb7 ... That's my BASE question, how could I wait on all the parts for the data to arrive?

这就像我说的它的重复，我们如何作出这样的填充成功的数据检索后阵列的服务，并在控制器后，这一切让数据发生，因为你可以看到我的截图，事情不同的顺序执行。

It's like I'm saying it on repeat, how do we make a service that populates the array after the successful data retrieval, and the controller getting data after all this happens, because as you can see in my screenshot, things run in a different order.

我有这样的code：

 var deferred = $q.defer();
            $http.get('../wordpress/api/core/get_category_posts/?category_id=14 ').success(function(data) {
                //we're emptying the array on every call
                theData = [];
                catName = data.category.slug;
                theData = data;
                theData.name = catName;
                aggregatedData.push(theData);
            });
            $http.get('../wordpress/api/core/get_category_posts/?category_id=15 ').success(function(data) {
                theData = [];
                catName = data.category.slug;
                theData = data;
                theData.name = catName;
                aggregatedData.push(theData);
            });
            $http.get('../wordpress/api/core/get_category_posts/?category_id=16 ').success(function(data) {
                theData = [];
                catName = data.category.slug;
                theData = data;
                theData.name = catName;
                aggregatedData.push(theData);
            });
            $http.get('../wordpress/api/core/get_category_posts/?category_id=17 ').success(function(data) {
                theData = [];
                catName = data.category.slug;
                theData = data;
                theData.name = catName;
                aggregatedData.push(theData);
            });
            //deferred.resolve(aggregatedData);
            $timeout(function() {
                deferred.resolve(aggregatedData);
            }, 1000);
            /*//deferred.reject('There is a connection problem.');
            if (myservice._initialized) {
                $rootScope.$broadcast('postsList', deferred.promise);
            }*/
            //myservice._initialized = true;
            myservice = deferred.promise;
            return deferred.promise;

有关我的生活我不明白为什么我把超时使所得到的阵列时推迟？

For the life of me I can't understand why do I have to put a timeout when passing the resulting array to defer ?

不应该的原则是这样，推迟信息来等待，然后返回承诺？那是什么1秒存在的意义呢？从我的理解推迟应该可以，只要需要等待API返回的结果和回报承诺的数据。

Shouldn't the principle be like, defer waits for the information to come and then returns the promise? What is the point of that 1 second there? From what I understand defer should be able to wait as long as needed for the API to return the result and the return the promised data.

我真的很困惑，我撞了我的头靠在墙上的最后两个小时，因为我没有在我的控制器接收到任何数据，只有当我把超时那里。

I'm really confused, I've banged my head against the walls for the last two hours because I was not receiving any data in my controller, only when I put that timeout there.

推荐答案

恕我直言，我觉得有一个非常聪明的（优雅）的方式与 $ q.all 来做到这一点。

IMHO I think there's a much clever (and elegant) way to do this with $q.all.

请看看下面的code。

Please take a look at the code below.

我假设你想在一次与一个对所有大的阵列上的结果返回数据。

I am assuming that you want to return the data at once with all the results aggregated on a big array.

var myApp = angular.module('myApp', []);

myApp.factory('myService', function ($http, $q) {
    return {
        getAllData: function () {
            return $q.all([
                $http.get('../wordpress/api/core/get_category_posts/?category_id=14'),
                $http.get('../wordpress/api/core/get_category_posts/?category_id=15'),
                $http.get('../wordpress/api/core/get_category_posts/?category_id=16'),
                $http.get('../wordpress/api/core/get_category_posts/?category_id=17')
            ]).then(function (results) {
                var aggregatedData = [];
                angular.forEach(results, function (result) {
                    aggregatedData = aggregatedData.concat(result.data);
                });
                return aggregatedData;
            });
        }
    };
});

您可以在上面看到的 aggregatedData 只有在所有异步调用都通过 $ q.all 。

You can see above that the aggregatedData is only generated once all the async calls are completed via the $q.all.

您只需要包括服务作为依赖到您的控制器之一，例如，并调用这样的服务 myService.getAllData（）

You just need to include the service as dependency into one of your controllers, for example, and call the service like this myService.getAllData()

希望帮助或只是让我知道，如果你需要一个完整的工作的例子，我可以提供一个！ ：）

Hope that helps or just let me know if you need a full working example and I can provide one! :)

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