Javascript AngularJS，AngularMaterial-尽管$scope上存在对象，但HTML不呈现

我已经广泛地寻找这个问题的解决方案，但似乎找不到。这里的任何帮助都将不胜感激

基础知识：

<md-tabs md-dynamic-height md-border-bottom md-center-tabs><md-tab label="Artists">
    <md-content id="tab_background" class="md-padding">
        <div class="query_results hide_link" layout-padding>
            <a ng-repeat="artist in results  | filter: searchText"
               href="/#/artist/{{artist.selectedMedium}}/{{artist.uid}}">
                <md-card>
                    <img ng-src="{{artist.profImg}}" class="md-card-image" alt="Washed Out">
                    <md-card-header>
                        <div id="card_play_button_included">
                            <md-card-header-text>
                                <span class="hide_link md-title">{{artist.name}}{{artist.name_last}}</span>
                                <span class="hide_link md-subhead">{{artist.selectedSubmedium[0]}}</span>
                                <span class="hide_link md-caption">{{artist.neighborhood}}</span>
                            </md-card-header-text>
                        </div>
                    </md-card-header>
                    <md-card-actions layout="row" layout-align="end center">
                    </md-card-actions>
                </md-card>
            </a>
        </div>
    </md-content>
    </md-tab>
        <md-tab label="Events">
    </md-tab>
</md-tabs>

  $scope.getArtists = function(medium){
    //resetting results array
    $scope.firstArray = [];
    $scope.results = [];
    var Medium = medium.name;
    firebase.database().ref('/Artists/' + Medium).once('value').then(function(snapshot){
      console.log(snapshot.val());
      var obj = snapshot.val();
      for (var key in obj) {
        var innerObj = obj[key]
        innerObj.uid = key;
        console.log(innerObj);
        $scope.firstArray.push(innerObj);
      }
      $scope.results = $scope.firstArray;
      $scope.runSpinner();
    })
  }

• 利用角材质选项卡
• 从下拉列表中选择项目后，将调用firebase数据库并返回响应，该响应将放入$scope上的数组中
• HTML在此响应对象上使用ng repeat

问题：

• 尽管响应对象存在于作用域中，但html不会呈现任何内容，直到用户“单击”视图上的另一个按钮——任何按钮。事实上，用户只需触摸/单击屏幕上的某个内容，然后渲染结果

• 如果用户调用数据库以获取特定介质（即绘画）中的艺术家，但未单击屏幕上的任何内容，则不会显示任何结果，尽管$scope中存在响应对象

我被难住了

HTML:

<md-tabs md-dynamic-height md-border-bottom md-center-tabs><md-tab label="Artists">
    <md-content id="tab_background" class="md-padding">
        <div class="query_results hide_link" layout-padding>
            <a ng-repeat="artist in results  | filter: searchText"
               href="/#/artist/{{artist.selectedMedium}}/{{artist.uid}}">
                <md-card>
                    <img ng-src="{{artist.profImg}}" class="md-card-image" alt="Washed Out">
                    <md-card-header>
                        <div id="card_play_button_included">
                            <md-card-header-text>
                                <span class="hide_link md-title">{{artist.name}}{{artist.name_last}}</span>
                                <span class="hide_link md-subhead">{{artist.selectedSubmedium[0]}}</span>
                                <span class="hide_link md-caption">{{artist.neighborhood}}</span>
                            </md-card-header-text>
                        </div>
                    </md-card-header>
                    <md-card-actions layout="row" layout-align="end center">
                    </md-card-actions>
                </md-card>
            </a>
        </div>
    </md-content>
    </md-tab>
        <md-tab label="Events">
    </md-tab>
</md-tabs>

  $scope.getArtists = function(medium){
    //resetting results array
    $scope.firstArray = [];
    $scope.results = [];
    var Medium = medium.name;
    firebase.database().ref('/Artists/' + Medium).once('value').then(function(snapshot){
      console.log(snapshot.val());
      var obj = snapshot.val();
      for (var key in obj) {
        var innerObj = obj[key]
        innerObj.uid = key;
        console.log(innerObj);
        $scope.firstArray.push(innerObj);
      }
      $scope.results = $scope.firstArray;
      $scope.runSpinner();
    })
  }

我使用$scope.apply（）解决了这个问题