A brief discussion on how to use ng-class in AngularJS

There are three methods:

1. Binding through $scope (not recommended)
2. Binding through object array
3. Binding through key/value pairs

Implementation method:

1. Through $scope Binding (not recommended):

function ctrl($scope) { 
  $scope.className = "selected";
}

<div class="{{className}}"></div>

2. Binding through object array:

function ctrl($scope) { 
  $scope.isSelected = true;
}

<div ng-class="{true:&#39;selected&#39;,false:&#39;unselected&#39;}[isSelected]"></div>

When isSelected is true, increase the selected style; when isS When elected is false , add unselected style.

3. Binding through key/value pairs:

function ctrl($scope) { 
  $scope.isA = true;
  $scope.isB = false;
  $scope.isC = false;
}

<div ng-class="{&#39;A&#39;:isA,&#39;B&#39;:isB,&#39;C&#39;:isC}"></div>

When isA is true, add style A; when isB is true, add style B; when isC is true, Add C style.

<ion-list>
  <ion-item ng-repeat="project in projects" ng-click="selectProject(project, $index)" ng-class="{active: activeProject == project}">
    {{project.title}}
  </ion-item>
</ion-list>

Create ion-item based on the projects loop. When the activeProject is the project currently looped to, add the active style.

Some notes:

1. The first method is not recommended because controller $scope should only have data and behavior

2. ng-class adds related styles and can be used together with class