$scope.$apply() 调用是否适合这种情况？

Question

AngularJS 的新手（和 JavaScript 坦率地说），但根据我收集到的信息，只有在 [= 之外发生更改时才需要显式调用 $scope.$apply() 21=]的雷达。下面的代码（从 this plunker 粘贴）让我认为这不是需要调用的情况，但这是我让它工作的唯一方法。我应该采取其他方法吗？

index.html:

<html ng-app="repro">
  <head> 
    ...
  </head>
  <body class="container" ng-controller="pageController">
    <table class="table table-hover table-bordered">
        <tr class="table-header-row">
          <td class="table-header">Name</td>
        </tr>
        <tr class="site-list-row" ng-repeat="link in siteList">
          <td>{{link.name}}
            <button class="btn btn-danger btn-xs action-button" ng-click="delete($index)">
              <span class="glyphicon glyphicon-remove"></span>
            </button>
          </td>
        </tr>
    </table>
  </body>
</html>

script.js:

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

var DataStore = repro.service('DataStore', function() {
  var siteList = [];

  this.getSiteList = function(callback) {
    siteList = [ 
      { name: 'One'}, 
      { name: 'Two'}, 
      { name: 'Three'}];

    // Simulate the async delay
    setTimeout(function() { callback(siteList); }, 2000);
  }

  this.deleteSite = function(index) {
    if (siteList.length > index) {
      siteList.splice(index, 1);
    }
  };
});

repro.controller('pageController', ['$scope', 'DataStore', function($scope, DataStore) {
  DataStore.getSiteList(function(list) {

    $scope.siteList = list; // This doesn't work
    //$scope.$apply(function() { $scope.siteList = list; }); // This works

  });

  $scope.delete = function(index) {
    DataStore.deleteSite(index);
  };
}]);

Answer 1

setTimeout(function() { callback(siteList); }, 2000);

此行将带您离开 Anglar 的摘要循环。您可以简单地将 setTimeout 替换为 Angular 的 $timeout 包装器（您可以将其注入您的 DataStore 服务），并且您不需要 $scope.$apply.

Answer 2

setTimeout 是 async 事件，被视为超出 angular 上下文，因此它不运行摘要周期。当你做这样的事情时，你需要手动运行它，但更喜欢使用 $timeout.

相反，angular 确实提供了一个 $timeout 服务，其工作方式与 setTimeout 相同，但在执行回调函数后，它会调用 $scope.$apply()

$timeout(function() { callback(siteList); }, 2000);

Special thing about the $timeout is that it runs the digest cycle in safer way. It gives you a guarantee that it will not conflict with any currently running digest cycle. Behind the scenes, when you call function inside the $timeout, it checks whether there is any digest cycle running or not by checking $scope.root.$$phase, if it's in the digest phase, it places that digest cycle in queue and runs it after completion of that digest cycle.

$scope.$apply() 调用是否适合这种情况？

Is the $scope.$apply() call warranted for this scenario?

javascript

angularjs

angularjs-service

angularjs-scope

angularjs-digest