無法更新angular.forEach循環中的全局變量

我似乎在嘗試修改Angular.forEach循環內的全局變量時被卡住了。無法更新angular.forEach循環中的全局變量

我可以修改變量的罰款，但我似乎無法得到該變化適用於變量時訪問的循環之外。

我已經嘗試了各種'var self = this'，並在整個循環中使用'this.addresses = []'來訪問數組，但導致了同樣的問題。當我得到我的「回報」聲明時，我的變化就失去了。

下面的代碼：

$scope.getLocation = function(val) { 
var geocoderRequest = { 
    address: String(val), 
    componentRestrictions: { 
     'country': 'US' 
    } 
}; 
var addresses = [1]; // **** shows addresses as [1] ***** 
geocoder.geocode(geocoderRequest, function(callbackResult) { 
    console.log('address in geocode: ' + addresses); // ***** shows addresses as [1] **** 
    var f = ''; 
    angular.forEach(callbackResult.results, function(item) { 
     console.log('address in angular: ' + addresses); // **** shows addresses as [1] ***** 
     if (item.types[0] == 'locality') { 
      for (f = 1; f < item.address_components.length; f++) { 
       if (item.address_components[f].types[0] == 
        "administrative_area_level_1") { 
        addresses.push(item.address_components[0].short_name + ', ' + item.address_components[ 
         f].short_name); 
        console.log('addresses in each: ' + addresses); // **** shows addresses as [1, 2, 3] after I 'push' 2 and 3 into addresses array **** 
        break; 
       } 
      } 
     } 
    }); 
}); 
console.log('addresses outside: ' + addresses); // ***** shows addresses as [1] even after pushing 2 and 3 ***** 
return addresses;

};

來源

2014-09-24 James Gentes

您需要使用回調函數中的AJAX調用的結果來完成所有工作。有關詳細信息，請參閱[此問題]（http://stackoverflow.com/q/14220321/497356）。 – 2014-09-24 00:35:25

有太多這樣的類似問題，請檢查[this]（http://stackoverflow.com/questions/14220321/how-to-return-the-response-from-an-ajax-call）和[this]（ http://stackoverflow.com/questions/6847697/how-to-return-value-from-an-asynchronous-callback-function） – PSL 2014-09-24 00:35:59

查看https://docs.angularjs.org/api/ng/service/$q – Phil 2014-09-24 01:04:13

最終的解決方案是使用角度的$ q返回一個承諾：

在控制器：

.controller('LaunchformController', 
['$scope', '$q', 'geocoder', function ($scope, $q, geocoder) { 

    $scope.getLocation = function(val) {  
    var deferred = $q.defer();  

    geocoder.geocode({ address: String(val), componentRestrictions: {'country':'US'} }, 
     function(callbackResult) {   
     deferred.resolve(callbackResult); 
    }); 

    return deferred.promise;    
    }; 
}])

在服務：

.service('geocoder',function() { 
    this.geocode=function(georequest, outerCallback) { 
     var geocoder = new google.maps.Geocoder(); 
     geocoder.geocode(georequest, function(results, status) {   
     if (status == google.maps.GeocoderStatus.OK) {   
      var f = '';     
      var addresses = []; 
      angular.forEach(results, function(item){ 
      if (item.types[0] == 'locality') {   
       for (f=1;f<item.address_components.length;f++) {    
       if (item.address_components[f].types[0] == "administrative_area_level_1") { 
       addresses.push(item.address_components[0].short_name + ', ' + item.address_components[f].short_name);    
       break; 
       } 
       } 
      }    
      }); 
      outerCallback(addresses);   
     } else { 
      outerCallback({success:false, err: new Error('Geocode was not successful for the following reason: ' + status), results: null}); 
     } 
     }); 
    }; 
    })

來源

2014-09-24 23:30:17

無法更新angular.forEach循環中的全局變量

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