javascript - AngularJS 应用程序 : unable to update $index

Question

我正在使用 Giphy.com api 在 AngularJS 1.6 中开发一个应用程序。

有一个 Plunker HERE .

我遍历来自 https://api.giphy.com/v1/gifs/trending?api_key=myApyKey 的“giphys”数组，并将它们显示到 Bootstrap 4 卡片中。

有一个查看单个 giphy 功能。在我的 Controller 中:

// Create controller for the "giphyApp" module
app.controller("giphyCtrl", ["$scope", "$http", "$filter", "$timeout", function($scope, $http, $filter, $timeout) {
  var url = "https://api.giphy.com/v1/gifs/trending?api_key=PTZrBlrq8h2KUsRMeBuExZ5nHyn7dzS0&limit=120&rating=G";
  $scope.giphyList = [];
  $scope.search = "";
  $scope.filterList = function() {
    var oldList = $scope.giphyList || [];
    $scope.giphyList = $filter('filter')($scope.giphys, $scope.search);
    if (oldList.length != 0) {
      $scope.pageNum = 1;
      $scope.startAt = 0;
    };
    $scope.itemsCount = $scope.giphyList.length;
    $scope.pageMax = Math.ceil($scope.itemsCount / $scope.perPage);
  };

  $http.get(url)
  .then(function(data) {
      // giphy arary
      $scope.giphys = data.data.data;
      $scope.filterList();
      console.log($scope.giphys);

      // Paginate
      $scope.pageNum = 1;
      $scope.perPage = 24;
      $scope.startAt = 0;
      $scope.filterList();

      $scope.currentPage = function(index) {
        $("html, body").animate({
          scrollTop: 0
        }, 500);
        $timeout( function(){
          $scope.pageNum = index + 1;
          $scope.startAt = index * $scope.perPage;
        },0);
      };

      $scope.prevPage = function() {
        if ($scope.pageNum > 1) {
          $scope.pageNum = $scope.pageNum - 1;
          $scope.startAt = ($scope.pageNum - 1) * $scope.perPage;
        }
      };

      $scope.nextPage = function() {
        if ($scope.pageNum < $scope.pageMax) {
          $scope.pageNum = $scope.pageNum + 1;
          $scope.startAt = ($scope.pageNum - 1) * $scope.perPage;
        }
      };

      $scope.selectedIndex = null;
      $scope.selectedGiphy = null;

      $scope.fetchSinglegGiphy = function(giphy, index) {
        console.log(index);
        $scope.selectedIndex = index;
        $scope.selectedGiphy = giphy;
      }
    });
}]);

网格

<div class="row grid" ng-if="giphyList.length > 0">
  <div data-ng-repeat="giphy in giphyList | limitTo : perPage : startAt" 
       class="col-xs-12 col-sm-6 col-lg-4 col-xl-3 d-flex mb-4">
    <div class="giphy d-flex flex-column w-100">
      <div class="thumbnail pb-2 text-center" data-toggle="modal"
           data-target="#giphyModal"
           ng-click="fetchSinglegGiphy(giphy, $index)">
        <img ng-src="{{giphy.images.downsized.url}}" class="img-fluid">
      </div>
      <div class="text mt-auto">
        <p class="m-0 meta">{{giphy.import_datetime | dateParse | date : "MMMM dd y" }}</p>
        <p class="rating m-0">
          <i class="fa fa-star" aria-hidden="true"></i> {{giphy.rating | capitalize}}
        </p>
        <ul class="list-unstyled mb-0 text-center">
          <li ng-if="giphy.username != ''" class="text-muted">{{giphy.type | capitalize}} file uploaded by
            <br><strong>{{giphy.username | capitalize }}</strong>
          </li>
          <li ng-if="giphy.username == ''" class="text-muted">{{giphy.type | capitalize}} file uploaded by
            <br> <strong>Unknown</strong>
          </li>
          <li class="h6">{{giphy.title | titlecase }}</li>
        </ul>
      </div>
    </div>
  </div>
</div>

模态

<div class="modal fade" id="giphyModal">
  <div class="modal-dialog">
    <div class="modal-content">
      <div class="modal-header">
        <h4 class="modal-title h-3">{{selectedGiphy.title | titlecase }}</h4>
        <button type="button" class="close" data-dismiss="modal">
        <span>&times;</span>
        </button>
      </div>
      <div class="modal-body">
        <div class="row">
          <div class="col-12">
            <div class="image image text-center">
              <img ng-src="{{selectedGiphy.images.original.url}}"
                   alt="{{selectedGiphy.title }}" class="img-fluid">
            </div>
          </div>
        </div>
      </div>
      <div class="modal-footer justify-content-between">
        <div class="text-muted">Image ID: {{selectedGiphy.id}}</div>
        <div class="btn-group btn-group-sm">
          <button type="button" class="btn btn-success" data-dismiss="modal">
             <i class="fa fa-times-circle"></i> Close
          </button>
        </div>
      </div>
    </div>
  </div>
</div>

应用程序的这一部分工作正常。

我曾期望能够轻松地向上面的模态添加下一个和上一个 giphy:

<div class="controls text-center">
    <a href="#" ng-click="fetchSinglegGiphy(giphy, $index = $index - 1)" class="left">
      <i class="fa fa-chevron-left"></i>
    </a>
    <a href="#" ng-click="fetchSinglegGiphy(giphy, $index = $index + 1)" class="right">
      <i class="fa fa-chevron-right"></i>
    </a>
</div>

令我惊讶的是，这不起作用。当我单击任何一个控件时，GIF 文件保持不变，但模式中的所有文本都消失了。

问题:

1. 这种方法有什么问题？
2. 您看到可行的替代方案了吗？

Answer 1

index.html

<div class="modal fade" id="giphyModal">
   <div class="modal-dialog">
      <div class="modal-content">
         <div class="controls text-center">
            <a href="#" ng-click="fetchSinglegGiphyModal('prev')" class="left"><i class="fa fa-chevron-left"></i></a>
            <a href="#" ng-click="fetchSinglegGiphyModal('next')" class="right"><i class="fa fa-chevron-right"></i></a>
         </div>
         <div class="modal-header">
            <h4 class="modal-title h-3">
               {{ selectedGiphy.title | capitalize }}
            </h4>
            <button type="button" class="close" data-dismiss="modal">
               <span>&times;</span>
            </button>
         </div>
         <div class="modal-body">
            <div class="row">
               <div class="col-12">
                  <div class="image image text-center">
                     <img ng-src="{{ selectedGiphy.images.original.url }}" alt="{{ selectedGiphy.title }}" class="img-fluid" image-on-load ng-hide="modalImageLoading" />
                     <div class="spinner-border" ng-if="modalImageLoading"></div>
                  </div>
               </div>
            </div>
         </div>
         <div class="modal-footer justify-content-between">
            <div class="text-muted">
               Image ID: {{ selectedGiphy.id }}
            </div>
            <div class="btn-group btn-group-sm">
               <button type="button" class="btn btn-success" data-dismiss="modal">
                  <i class="fa fa-times-circle"></i> Close
               </button>
            </div>
         </div>
      </div>
   </div>
</div>

修改:

<a href="#" ng-click="fetchSinglegGiphyModal('prev')" class="left"><i class="fa fa-chevron-left"></i></a>
<a href="#" ng-click="fetchSinglegGiphyModal('next')" class="right"><i class="fa fa-chevron-right"></i></a>

fetchSinglegGiphyModal 根据作用于参数 prev 或 next 的条件处理上一个和下一个 Giphy我们在函数中传递的值。

我还添加了以下代码来引入bootstrap自带的loader来表示正在后台加载GIF图片。

<div class="image image text-center">
   <img ng-src="{{ selectedGiphy.images.original.url }}" alt="{{ selectedGiphy.title }}" class="img-fluid" image-on-load ng-hide="modalImageLoading" />
   <div class="spinner-border" ng-if="modalImageLoading"></div>
</div>

app.js

$scope.modalImageLoading = false;

$scope.fetchSinglegGiphy = function (giphy, index) {
   $scope.selectedIndex = index;
   $scope.selectedGiphy = giphy;
   $scope.modalImageLoading = true;
};

$scope.fetchSinglegGiphyModal = function (dir) {
   let selectedGiphy = null;
   if (dir === "prev") $scope.selectedIndex -= 1; // To load previous
   else if (dir === "next") $scope.selectedIndex += 1; // To load next

   selectedGiphy = $scope.giphyList[$scope.selectedIndex];
   if (selectedGiphy) {
      $scope.selectedGiphy = selectedGiphy;
      $scope.modalImageLoading = true;
   }
};

$scope.fetchSinglegGiphyModal 作用于我们传入参数的条件，并显示相应的 Giphy 数据。

我已经实现了一个自定义指令来显示图像元素并在下载图像时隐藏加载程序。这是指令代码:

app.directive('imageOnLoad', function () {
   return {
      restrict: 'A',
      controller: 'giphyCtrl',
      link: function (scope, element, attrs) {
         element.bind('load', function () {
            scope.$apply(function () {
               scope.modalImageLoading = false;
            });
         });
      }
   }
});

这是修改后的 plunker code .

希望对您有所帮助!