我正在尝试从firebase中获取一些数据，我正在使用angular firebase插件。我在检查器中仔细检查了调试，url是正确的。它会返回，这意味着url是正确的，但回调的参数是未定义的。

我正在使用loaded，因为我需要它发射一次。我尝试了有价值但有羞耻感的东西。

我想我今天已经把所有的精力都用在了这件事上，所以再发表一个意见就好了。

附言：我真的很奇怪他们为什么不使用承诺而不是回调。

来自angular+firebase工厂的碎片

     var seekMatch = function(player) {
        var deferred = $q.defer();
        
        angular.forEach(matches.$getIndex(), function(matchId) {
            var matchRef = firebaseRef('matches/' + matchId);  // <-- double checked, the url sends me to the correct firebase record
            var matchDB = $firebase(matchRef);
            
            matchDB.$on('loaded', function(data) {
                console.log(data);   // <----- return's undefined
                if (matchMakingFormula(data.playerA, player)) {
                    if (!match) {
                        match = data;
                        deferred.resolve(match);
                    }
                }
            });
        });
        
        return deferred.promise;
    };

我在这里添加所有代码是为了让你更好地了解我要做的事情。

我的fb.match.service的完整代码

'use strict';
angular.module('angularfireApp')
.factory('FBmatchService', ['$rootScope' , '$q', '$firebase', 'firebaseRef',
function ($rootScope, $q, $firebase, firebaseRef) {
  // Service logic
  var matchesRef = firebaseRef( '/matches/' );
  var matches = $firebase(matchesRef);
  var match = null;
  var matchMakingFormula = function (playerA , playerB) {
    return playerA.type !== playerB.type
    && distanceFormula( playerA.location.lat , playerA.location.long, playerB.location.lat , playerB.location.long ) < 1
  };
  var distanceFormula = function (lat1 , lon1 , lat2, lon2) {
    var R = 6371; // km
    var dLat = (lat2-lat1).toRad();
    var dLon = (lon2-lon1).toRad();
    var lat1 = lat1.toRad();
    var lat2 = lat2.toRad();
    var a = Math.sin(dLat/2) * Math.sin(dLat/2) + Math.sin(dLon/2) * Math.sin(dLon/2) * Math.cos(lat1) * Math.cos(lat2);
    var c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a));
    var d = R * c;
    return d;
  };
  var getMatch = function (matchId) {
    match = matches.$getIndex(matchId);
    return match;
  };
  var seekMatch = function ( player ) {
    var deferred =  $q.defer();
    angular.forEach(matches.$getIndex() , function (matchId){
      var matchRef = firebaseRef( 'matches/'+matchId );
      var matchDB = $firebase( matchRef );
      matchDB.$on('loaded',function (data) {
        console.log(data);
        if (matchMakingFormula(data.playerA , player)) {
          if (!match) {
            match = data;
            deferred.resolve(match);
          }
        }
      });
    });
    return deferred.promise;
  };

  // Public API here
  return {
    get: function (matchId) {
      return getMatch(matchId);
    },
    seek: function (points) {
      return seekMatch(points);
      //return match.promise;
    },
    new: function (points) {
      //return match.promise;
    },
    join: function (match) {
      //return match;
    }
  };
}]);

提前谢谢。干杯，玩得开心！