UI-Select和AngularJS的问题

Question

我目前在控制台中收到错误消息：

    Error: [ui.select:items] Expected an array but got '{}'.at select.min.js:7
at select.min.js:7
at $watchCollectionAction (angular.js:16527)
at Scope.$digest (angular.js:16664)
at Scope.$apply (angular.js:16928)
at done (angular.js:11266)
at completeRequest (angular.js:11464)
at XMLHttpRequest.requestLoaded (angular.js:11405)

我从已经在邮递员中检查的网络服务返回内容，该网络服务返回一个数组，80％的时间它不能填充下拉菜单和其他20％的我得到错误的时间但它仍然有效。

代码非常简单：

    function selectCtrl($scope, $http) {

$scope.person = {};

$scope.option = {};
$scope.options = [];


var onUserComplete = function(response){
    $scope.options = response.data;
    console.log(response.data);
}


$http.get("http://localhost/api/user")
    .then(onUserComplete);

}

HTML看起来像这样：

                        <ui-select ng-model="option.selected" theme="bootstrap" on-select="onSelectCallback($item)">
                            <ui-select-match placeholder="Select or search a person">{{$select.selected.username}}</ui-select-match>
                            <ui-select-choices repeat="item in options">
                                <div ng-bind-html="item.username | highlight: $select.search"></div>
                            </ui-select-choices>
                        </ui-select>

邮递员的数据如下所示：

    [
{
    "id": 1,
    "username": "username1"
},
{
    "id": 2,
    "username": "username2"
}