Angular ngClass is not updating my classes even though my condition change as expected

问题

I have something like this in a template I am creating

<div ui-view id="app" class="nng-3" ng-class="{ 'app-mobile': app.isMobile, 'app-navbar-fixed': app.layout.isNavbarFixed, 'app-sidebar-fixed': app.layout.isSidebarFixed, 'app-sidebar-closed': app.layout.isSidebarClosed, 'app-footer-fixed': app.layout.isFooterFixed }"></div>

The values app.layout.isNavbarFixed, etc are initialized with either zero or one, and for the first time the page loads the appropriate classes are inserted into my div. Any change after that though, by means of a button that sets those values, is not reflected on my class attributes by ng-class.

If I directly print those variables in my template, eg. {{app.layout.isSidebarFixed}} I can see them changing from true to false and vice versa, but ng-class will not update or remove any new classes.

I am not sure where to begin and look for the solution for this since with my limited knowledge I cant spot any obvious mistake immediately. Does anyone have any idea on what causes this issue?

回答1:

A workaround of mine is to manipulate a model variable just for the ng-class toggling:

1) Whenever my list is empty, I update my model:

$scope.extract = function(removeItemId) {
    $scope.list= jQuery.grep($scope.list, function(item){return item.id != removeItemId});
    if (!$scope.list.length) {
        $scope.liststate = "empty";
    }
}

2) Whenever my list is not empty, I set another state

$scope.extract = function(item) {
    $scope.list.push(item);
    $scope.liststate = "notempty";
}

3) I use this additional model on my ng-class:

ng-class="{'bg-empty': liststate == 'empty', 'bg-notempty': liststate == 'notempty'}"

Update*: Also you can add any other states if needed and use at ng-class like:

ng-class="{'bg-empty': liststate == 'empty', 'bg-notempty': liststate == 'notempty', 'bg-additional-state', liststate == 'additional-state'}"

Because you know, an initially empty list state is not equal with a list which is emptied by command.

回答2:

Probably the ng-class implementation is not considering "0" to be "false" as you expect, because it's doing an strict comparision with ===.

Try expressing the conditions like this:

ng-class="{ 'app-mobile': app.isMobile == 0, 'app-navbar-fixed': app.layout.isNavbarFixed == 0, ...

回答3:

Tried your variant. Have everything working. Please, check if your button click event is on $scope and AngularJS knows, that values changed.

For example, if function triggered by native DOM Event (some jQuery table updated or something) than you should use $apply function, to reflect changes on scope. Something like this:

$scope.eventHandler = function(e) {
  $scope.$apply(function(){ $scope.someProp = e.value;}
}

In the mean time, check this jsfiddle

Update: Please check this jsfiddle out. This works in AngularJS 1.4.8, but doesn't in other, that support jsfiddle. From what I know, it's not really a best idea to do an assignment inside of expression, the controller is meant for this thing.

来源：https://stackoverflow.com/questions/35651732/angular-ngclass-is-not-updating-my-classes-even-though-my-condition-change-as-ex

标签

javascript

html

angularjs

ng-class