在 ng-repeat 动画之前将 Angular ng-class 设置为 $apply [英] Getting Angular ng-class to $apply before an ng-repeat animation

问题描述

我有一个动画，可以根据单击的按钮向左或向右移动 ng-repeat 中的元素.

在一次操作中，我设置了一个 ng-class(动画类)，然后移除了触发动画的元素，但在应用动画之前它似乎无法识别对 ng-class 的更改，除非我使用 $scope.$apply()，但这会引发 $apply already in progress 错误.有没有办法不必使用 $scope.$apply()，或者摆脱那个错误?

这是工作小提琴(有错误).http://jsfiddle.net/noducks/6pFr2/

HTML

<div ng-repeat="元素中的元素" ng-class="elem.anim"><button ng-click="out(elem, 'left', $index)">左</button><button ng-click="out(elem, 'right', $index)">Right</button>

Javascript

var myApp = angular.module('myApp',['ngAnimate']);函数 MyCtrl($scope) {$scope.elements = [{动画:''}，{动画:''}，{动画:''}，{动画:''}，{动画:''}];$scope.out = 函数(元素，目录，索引){elem.anim = direc;$scope.$apply();$scope.elements.splice(index, 1);};}

CSS

.left.ng-leave {-webkit-transition:所有线性 1；过渡:所有线性1s；}.left.ng-leave.ng-leave-active{-ms-transform: translateX(-100%);-o-transform: translateX(-100%);-moz-transform: translateX(-100%);-webkit-transform: translateX(-100%);变换:translateX(-100%);}.left.ng-离开{-ms-transform: translateX(0%);-o-transform: translateX(0%);-moz-transform: translateX(0%);-webkit-transform: translateX(0%);变换:translateX(0%);}.right.ng-离开{-webkit-transition:所有线性 1；过渡:所有线性1s；}.right.ng-leave.ng-leave-active {-ms-transform: translateX(100%);-o-transform: translateX(100%);-moz-transform: translateX(100%);-webkit-transform: translateX(100%);变换:translateX(100%);}.right.ng-离开{-ms-transform: translateX(0%);-o-transform: translateX(0%);-moz-transform: translateX(0%);-webkit-transform: translateX(0%);变换:translateX(0%);}

解决方案

问题是，如果从 DOM 中删除重复元素，则它们没有任何 css 动画信息.我想您已经注意到，如果您删除 $apply 调用，元素会立即从 DOM 中删除.此外，您可能已经注意到，如果您对动画进行硬编码，动画会按预期发生，例如设置 class="left" 或 class="right".

要使 ngAnimation 像您期望的那样发生，$animate 服务和浏览器需要您尝试制作动画的信息.但是只有在 DOM 操作发生时，浏览器和 $animate 服务才知道这些信息.

如何解决这个问题:您需要在 DOM 更新 css 类后对 $scope.elements 进行更改.因此，您需要延迟一个摘要循环的 DOM 操作.这可以通过 $timeout 服务完成(有关更多信息，请参阅此答案AngularJS:$evalAsync 与 $timeout):

$scope.out = function(elem, direc, index) {elem.anim = direc;$超时(功能(){$scope.elements.splice(index, 1);});};

I have an animation that animates an element in an ng-repeat to the left or right depending on which button is clicked.

In one manoeuvre, I set a ng-class (the animation class) and then remove the element, which triggers the animation, but it doesn't seem to recognise the change to the ng-class before the animation is applied, unless I use a $scope.$apply(), but this throws up a $apply already in progress error. Is there a way to not have to use the $scope.$apply(), or to get rid of that error?

Here is the working fiddle (with errors). http://jsfiddle.net/noducks/6pFr2/

HTML

<div ng-controller="MyCtrl" style="text-align: center">
<div ng-repeat="elem in elements" ng-class="elem.anim">
   <button ng-click="out(elem, 'left', $index)">Left</button>
   <button ng-click="out(elem, 'right', $index)">Right</button>
</div>
</div>

Javascript

var myApp = angular.module('myApp',['ngAnimate']);

function MyCtrl($scope) {
$scope.elements = [
    {anim: ''},
    {anim: ''},
    {anim: ''},
    {anim: ''},
    {anim: ''}
];

$scope.out = function(elem, direc, index) {
    elem.anim = direc;
    $scope.$apply();
    $scope.elements.splice(index, 1);
};
}

CSS

.left.ng-leave {
  -webkit-transition:all linear 1s;
  transition:all linear 1s;
}

.left.ng-leave.ng-leave-active{
    -ms-transform: translateX(-100%); 
    -o-transform: translateX(-100%);
    -moz-transform: translateX(-100%);
    -webkit-transform: translateX(-100%);
    transform: translateX(-100%);
}

.left.ng-leave {
  -ms-transform: translateX(0%); 
  -o-transform: translateX(0%);
  -moz-transform: translateX(0%);
  -webkit-transform: translateX(0%);
  transform: translateX(0%);
}

.right.ng-leave {
    -webkit-transition:all linear 1s;
    transition:all linear 1s;
}

.right.ng-leave.ng-leave-active {
    -ms-transform: translateX(100%); 
    -o-transform: translateX(100%);
    -moz-transform: translateX(100%);
    -webkit-transform: translateX(100%);
    transform: translateX(100%);
}

.right.ng-leave {
    -ms-transform: translateX(0%); 
    -o-transform: translateX(0%);
    -moz-transform: translateX(0%);
    -webkit-transform: translateX(0%);
    transform: translateX(0%);
}

解决方案

The problem is that your repeated elements do not have any css animation information if they are removed from the DOM. I guess you have noticed that the elements are immediately removed from the DOM if you remove the $apply call. Also you may have noticed that the animation happens as expected if you hardcode the animation e.g. set class="left" or class="right".

To make the ngAnimation happen as you expect the $animate service and the browser need the information what you are trying to animate. But these informations are known to the browser and the $animate service only when the DOM manipulations has taken place.

How to solve this: you need to make the changes to the $scope.elements after the css class is updated at the DOM. So you need to delay the DOM manipulation for one digest loop. This can be done by the $timeout service (please see this answer for more information AngularJS : $evalAsync vs $timeout):

$scope.out = function(elem, direc, index) {
    elem.anim = direc;
    $timeout(function(){
       $scope.elements.splice(index, 1);
    });
}; 

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