angularjs - AngularJS：如果使用http获取数据，我将如何从工厂返回值

Question

我有这个工厂的角度：

'use strict';

angular.module('finansiiApp')
  .factory('transactions', function ($http) {
    var transactions = [];
    $http.get("/api/transactions.json")
      .success(function(data, status){
        transactions = data;
      });

    // Public API here
    return {
      getTransactions: function () {
        return transactions;
      },
      addTransaction: function(transaction){
        transactions.push(transaction);
      }
    };
  });

这是我的控制器：

'use strict';

angular.module('finansiiApp')
  .controller('MainCtrl', function ($scope, transactions) {
    $scope.searchText = "";
    $scope.filterPrimanja = $scope.filterTrosoci = true;
    console.log(transactions);
    $scope.transactions = transactions.getTransactions();
    $scope.clicked = function(index){
      console.log(index);
    }
  });

现在您可能已经猜到了，我在控制器中的数据（我在其中调用 getTransactions 方法）不会在成功时更新。我将如何进行这项工作？

Answer 1

你可以改变一些事情。（以及您可以更改它们的方法）。1 是最建议/最正确的。

1. 在控制器中使用承诺和回调，所以......

   // your controller... ($scope.transactions line)
   transactions.getTransactions().then(function(data){
       $scope.transactions = data;
   }
   
   // your service..
   angular...factory('transactions',function($http,$q){
       var transactions = [];
       return {
           getTransactions: function(){
              //is a request needed?
              if(transactions.length > 0){
                  var deferred = $q.defer();
                  deferred.resolve(transactions);
                  return deferred.promise;
              }
              return $http.get("/api/transactions.json").then(function(result){
                  //modify collection of transactions...
                  transactions = result.data;
                  return transactions; // this is data ^^ in the controller
              });
           }
           addTransaction: function(transaction){
               //do more http stuff?
               //wrap function in promise so its consistent and will also run digest.
               var deferred = $q.defer();
               transactions.push(transaction);
               deferred.resolve(transactions);
               return deferred.promise;
           }
       }
   
   });
   

2. 修改var transactions = [];而不是仅仅抹去它。例如。迭代新数据并推送/弹出 unshift，concat w/e 以角度绑定的对象需要是幂等的

要记住的另一件事是服务只实例化一次。虽然控制器一直在创建和销毁。您可能不必每次都发出请求，所以在返回 $http 承诺之前，getTransactions您可以检查是否需要发出请求。然后手动使用一个promise。