Javascript AngularJS日期选择器未更新指令

因此，我密切关注AngularJS.org上的文档（在的Datepicker部分下），但到目前为止，当选择了新日期（默认日期除外）时，输入字段将更新，而不是指令。但是，该指令仅在手动编辑输入字段时更新。我是AngularJS的新手，但我到处都在搜索，似乎找不到这个问题的正确答案

这是我的控制器：

var QuizCntrl = function ($scope) {

// Sets the default date, making adjustments for meetings that would otherwise land on a weekend date.
$scope.date_selected = new Date();
$scope.date_selected.setHours(0,0,0,0);
if($scope.date_selected.getDay() == 3 || $scope.date_selected.getDay() == 4)
    $scope.date_selected.setDate($scope.date_selected.getDate() + 5);
else
    $scope.date_selected.setDate($scope.date_selected.getDate() + 3);

// Clears selection
$scope.clear = function () {
    $scope.date_selected = null;
};

  // Disable weekend selection
$scope.disabled = function(date, mode) {
    return ( mode === 'day' && ( date.getDay() === 0 || date.getDay() === 6 ) );
};

$scope.minDate = new Date();

// $scope.$watch('date_selected', function() {
// });


$scope.open = function($event) {
    $event.preventDefault();
    $event.stopPropagation();

    $scope.opened = true;
};

$scope.dateOptions = {
    formatYear: 'yy',
    startingDay: 0
};

$scope.initDate = new Date('2016-15-20');
$scope.formats = ["shortDate"];
$scope.format = $scope.formats[0];

})

以下是我的观点（仅适用于日期选择器）：

---

$scope.date\u selected=null
基本上是一个大禁忌。AngularJS的内部监视过程依赖于您保持对$scope对象的引用完好无损。您可以创建一个plunkr来处理示例吗？
        <div class="jumbotron" ng-controller="QuizCntrl"">
              <p class="input-group">
                    <input type="text" class="form-control" datepicker-popup="shortDate" ng-model="date_selected" is-open="opened" min-date="minDate" max-date="'2015-06-22'" datepicker-options="dateOptions" date-disabled="disabled(date, mode)" ng-required="true" close-text="Close" />
                    <span class="input-group-btn">
                           <button type="button" class="btn btn-default" ng-click="open($event)"><i class="glyphicon glyphicon-calendar"></i></button>
                     </span>
              </p>
              {{date_selected | date:'fullDate' }}
         </div>