運行代碼後先

Question

所以這是我的工廠代碼：

app.factory('simpleFactory', function ($http) { 
    var factory = {}; 

    factory.getArray = function (srchWord) { 

     **Here i have a code that uses $http to fill a array called result with values. 

      return result; 
     }; 

    return factory; 
}); 

這是我的範圍內的代碼：

$scope.search = function() { 

     $scope.arrayValue = simpleFactory.getArray($scope.searchWord); 

     $scope.booleanValue = ($scope.arrayValue.length <= 0); // <-- PROBLEM! This gets executed before getArray() is finished. 

}; 

我的問題是$scope.booleanValue = ($scope.arrayValue.length <= 0)在$scope.arrayValue已從$simpleFactory.getArray($scope.searchWord)獲得其價值之前執行。
所以我的問題是我怎麼能等到功能的getArray完成火我的代碼：

$scope.arrayValue = simpleFactory.getArray($scope.searchWord); 

Answer 1

首先從工廠方法getArray返回promise。

app.factory('simpleFactory', function ($http) { 
    var factory = {}; 

    factory.getArray = function (srchWord) { 

     return $http.query(....); // this returns promise; 
     }; 

    return factory; 
}); 

其次等待承諾解決使用然後。

scope.arrayValue = simpleFactory.getArray($scope.searchWord).then(function(data) { 
    $scope.arrayValue=data; 
    $scope.booleanValue = ($scope.arrayValue.length <= 0); 
}); 

閱讀有關什麼promise是，如何$http使用它們。

Answer 2

您可以將布爾值設置爲getArray函數的回調，也可以在arrayValue上設置監視並根據該值更新booleanValue。

$scope.search = function() { 

    simpleFactory.getArray($scope.searchWord, function(result) { 
     $scope.arrayValue = result; 
     $scope.booleanValue = ($scope.arrayValue.length <= 0); 
    }); 

    // or 

    // initialize the value 
    $scope.arrayValue = []; 

    // *then* set the value, so it triggers the change on the $watch below  
    $scope.arrayValue = simpleFactory.getArray($scope.searchWord); 

    $scope.$watch('arrayValue', function(newValue,oldValue) { 
     $scope.booleanValue = (newValue.length <= 0); 
    }); 

};