相关疑难解决方法(0)

我正在使用Ionic,并希望根据数据动态更改每个项目的背景颜色<ion-list>.我以为我会通过函数调用来返回正确的类

<ion-list>
  <ion-item ng-repeat="singleCase in allCases" ng-class="getBackgroundColour(singleCase)" class="item-avatar">
    <h2>{{singleCase.date}}</h2>
    <p>{{singleCase.caseType}}</p>
  </ion-item>
</ion-list>

这是目前的控制器

  .controller('AllCasesCtrl', ['$scope', '$log', 'dummyData', function($scope, $log, dummyData) {
    $scope.allCases = dummyData.cases;

    $scope.getBackgroundColour = function(singleCase){

      $log.log("getBackgroundColour called...singleCase type: " + singleCase.speciality);

      var colourMap = {
        speciality1: "speciality1Class",
        speciality2: "speciality2Class",
        speciality3: "speciality3Class"
      };

      return colourMap[singleCase.speciality];
    };

  }])

在检查控制台时,列表中的getBackgroundColour()每个函数被调用7次<ion-item>.为什么这样,我应该避免使用函数调用ng-class吗？