如何从基于回调的 API 创建 AngularJS Promise

wifiservice.js：

angular.module('app.WifiServices', [])
    .factory('WifiService', function(){
        var unique_array = angular.fromJson('[]');

        function win_wifi(e){
        alert("Success");
        }

        function fail_wifi(e){
        alert("Error");
        }

        function connectWifi(wifi_ssid){
          WifiWizard.connectNetwork(wifi_ssid, win_wifi, fail_wifi);
        }

        function listHandler(a){

      var network_array = [];
      for(var i=0; i<a.length; i++){
        network_array.push("SSID: " + a[i].SSID + " Signal: " + a[i].level);
      }

      unique_array = network_array.filter(function(elem, pos) {
        return network_array.indexOf(elem) == pos;
      });

      // alert("Wifi List Ready!");
    }

    function getScanResult(){
      WifiWizard.getScanResults(listHandler, failNetwork);
    }

    function successNetwork(e){
      window.setTimeout(function(){
        getScanResult();
      }, 3000);
    }

    function failNetwork(e){
      alert("Network Failure: " + e);
    }

    window.setTimeout(function(){
      WifiWizard.startScan(successNetwork, failNetwork);
    }, 1000);

        return {
          list: function(){
            return unique_array;
          },

          connectionToWifi: function(name){
            connectWifi(name);
          }
        };
    });

我的整个控制器：

app.controller('WifiController', ['$scope', 'WifiService', function($scope, WifiService) {

 $scope.wifiList = [];

 window.setTimeout(function() {
  $scope.wifiList = WifiService.list();
  // alert($scope.wifiList);
  $scope.$apply();
 }, 5000);

 $scope.getList = function() {
  $scope.wifiList = WifiService.list();
  return $scope.wifiList;
 }

 $scope.connectWifi = function(name) {
  WifiService.connectionToWifi(name);
 }

 $scope.checkin = function() {
  $scope.getList()
  .then(function(result) {
     console.log(result);
 });
}

}]);

我想做的是，调用 $scope.getList()，它返回周围 wifi SSID 的列表，然后在 $scope.checkin() 内处理这些数据。

由于扫描需要一些时间，我必须等待 getList 函数完成，这就是为什么我尝试使用 .then，但它给了我标题上所示的错误。有任何想法吗？

如何从基于回调的 API 创建 AngularJS Promise

从基于回调的 API 创建 AngularJS Promise，例如WifiWizard.connectNetwork https://github.com/hoerresb/WifiWizard#wifiwizardconnectnetworkssid-win-fail, use $q.defer https://docs.angularjs.org/api/ng/service/%24q#defer:

function connectWifi(wifi_ssid) {
   var future = $q.defer();
   var win_wifi = future.resolve;
   var fail_wifi = future.reject;
   WifiWizard.connectNetwork(wifi_ssid, win_wifi, fail_wifi);
   return future.promise;       
};

上面的例子返回一个$q 服务 https://docs.angularjs.org/api/ng/service/%24q承诺使用 API 的回调来解决或拒绝。