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The view is not updated in AngularJS

Posted by: admin November 7, 2017 Leave a comment

Questions:

Updating the model property has no effect on the view when updating the model in event callback, any ideas to fix this?

This is my service:

angular.service('Channel', function() {        
    var channel = null; 

    return {        
        init: function(channelId, clientId) {
            var that = this;        

            channel = new goog.appengine.Channel(channelId);
            var socket = channel.open();

            socket.onmessage = function(msg) {
                var args = eval(msg.data);              
                that.publish(args[0], args[1]);
            };
        }       
    };
});

publish() function was added dynamically in the controller.

Controller:

App.Controllers.ParticipantsController = function($xhr, $channel) {
    var self = this;

    self.participants = [];     

    // here publish function is added to service
    mediator.installTo($channel); 

    // subscribe was also added with publish        
    $channel.subscribe('+p', function(name) { 
        self.add(name);     
    });                 

    self.add = function(name) {     
        self.participants.push({ name: name });     
    }
};

App.Controllers.ParticipantsController.$inject = ['$xhr', 'Channel'];

View:

<div ng:controller="App.Controllers.ParticipantsController">      
    <ul>
        <li ng:repeat="participant in participants"><label ng:bind="participant.name"></label></li>
    </ul>

    <button ng:click="add('test')">add</button>
</div>

So the problem is that clicking the button updates the view properly, but when I get the message from the Channel nothings happens, even the add() function is called

Answers:

You are missing $scope.$apply().

Whenever you touch anything from outside of the Angular world, you need to call $apply, to notify Angular. That might be from:

  • xhr callback (handled by $http service)
  • setTimeout callback (handled by $defer service)
  • DOM Event callback (handled by directives)

In your case, do something like this:

// inject $rootScope and do $apply on it
angular.service('Channel', function($rootScope) {
  // ...
  return {
    init: function(channelId, clientId) {
      // ...
      socket.onmessage = function(msg) {
        $rootScope.$apply(function() {
          that.publish(args[0], args[1]);
        });
      };
    }
  };
});