angular ng-if or ng-show responds slow (2second de

问题:

I'm trying to show or hide a loading indicator on a button when a request is busy. I do that with angular by changing the $scope.loading variable when a request is loading or when it's done loading.

 $scope.login = function(){
     $scope.loading = true;
    apiFactory.getToken()
        .success(function(data){

        })
        .error(function(error){

        })
         .finally(function(){
               $timeout(function() {
                 $scope.loading = false;
               }, 0);
         });
 };

In the frontend:

<button ng-disabled="loading" class="button button-outline button-positive" type="submit">
Log in 
<span ng-if="loading" class="ion-refreshing"></span>
</button>

This works fine, but the loading icon (ion-refreshing) is shown for about 2 seconds, while the $scope variable is updated immediately. I tried $scope.$apply but that doesn't seem to be what's wrong here, the scope is updated just fine and immediately after the request. It's just the icon that isn't responding quickly enough.

Thanks for helping me understand this!

回答1:

Try removing ngAnimate if you're not using it from your app config and index.html page:

angular.module('myApp', [...'ngAnimate',...])

@Spock; if you still require the use of ngAnimate then leave your app config untouched and just add the following CSS:

.ng-hide.ng-hide-animate{
     display: none !important;
}

That will hide the animated icon straight after your condition is met.

As you can see we are setting .ng-hide-animate to hidden. This is what causes the delay as it waits for the animation to complete. You can add an animation to your hide event as the class name implies instead of hiding it as in the example above.

回答2:

I had the same issue, and worked-around it by using ng-class with the 'hidden' class name to hide the element instead of using ng-if or ng-show/ng-hide.

回答3:

I found some solutions here, but the best for me was overriding the styling for the .ng-animate class:

.ng-animate.no-animate {
    transition: 0s none;
    -webkit-transition: 0s none;
    animation: 0s none;
    -webkit-animation: 0s none;
}

In html:

<button ng-disabled="loading" class="button button-outline button-positive" type="submit">
    Log in 
    <span ng-if="loading" class="ion-refreshing no-animate"></span>
</button>

This is an example: http://jsfiddle.net/9krLr/27/

I hope help you.

回答4:

I was facing a similar issue, I used $scope.$evalAsync() to force update the binding.

It works like a charm.

Avoid using $scope.$apply as it can conflict with an already-running $digest phase.

if(selectedStatistics.length === 0 || selectedWorkgroups.length === 0){
    ctrl.isSaveDisabled = true;
    $scope.$evalAsync();
} else{
    ctrl.isSaveDisabled = false;
    $scope.$evalAsync();
}

回答5:

in angular version 1.5.x adding $scope.$apply() after the change in the condition done the job for me here is an example function

$scope.addSample = function(PDF)
        {
            var validTypes ="application/pdf";
            if(PDF.type == validTypes)
            {
                //checking if the type is Pdf and only pdf
                $scope.samplePDF= PDF.files[0];
                $scope.validError = false;
                $scope.$apply();
            }

            else
            {
                 $scope.validError = true;
                 $scope.samplePDF= null;
                 $scope.$apply();
            }


        }