为什么AngularJs的视图在异步Ajax调用后没有更新？

Question

Why the view is not updated to "Someone"?

 var app = angular.module('Async', []); app .controller('MainController', function($scope) { $scope.user = { name: "No one" }; jQuery.ajax("/" , { async: true, type: "POST", } ).always(function() { $scope.user.name = "Someone"; alert($scope.user.name); }); }); angular.bootstrap(document, ['Async']); 

 <div data-ng-controller="MainController"> <div data-ng-view="">User's name: {{ user.name }}</div> </div> <script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.js"></script> <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.js"></script> <script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular-route.js"></script> 

Answer 1

When you are doing asynchronous calls like this outside of the angular world, you need to inform angular of any changes that you've made. There are a couple ways to fix this problem:

First Option: Run $scope.$apply() within your callback to inform angular you are changing things:

jQuery.ajax("/"
  , {
    async: true,
    type: "POST",
  }
).always(function() {
  $scope.apply(function() {
    $scope.user.name = "Someone";
    alert($scope.user.name);
  })
});

Second Option (preferred): Replace the jQuery.ajax call with angular's built-in $http , which will take care of the $apply step for you:

app
  .controller('MainController', function($scope, $http) {
    $scope.user = {
      name: "No one"
    };

    $http({
      method: 'POST',
      url: '/'
    }, function(successResponse) {
      $scope.user.name = successResponse.data.name;
      alert($scope.user.name);
    });
  });

Answer 2

You use jquery instead of angular $http service to make ajax request, so you should manually call $scope.$apply() after scope changes.

 var app = angular.module('Async', []); app .controller('MainController', function($scope) { $scope.user = { name: "No one" }; jQuery.ajax("/" , { async: true, type: "POST", } ).always(function() { $scope.user.name = "Someone"; $scope.$apply(); alert($scope.user.name); }); }); angular.bootstrap(document, ['Async']); 

 <div data-ng-controller="MainController"> <div data-ng-view="">User's name: {{ user.name }}</div> </div> <script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.js"></script> <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.js"></script> <script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular-route.js"></script> 

Answer 3

The problem is that your ajax handler is running outside AngularJS. You can replace your jQuery ajax call by AngularJs $http or use $scope.$apply (see: https://docs.angularjs.org/api/ng/type/$rootScope.Scope )