Display online and offline (e.g. airplane) mode in an Ember.js App

问题

Can an Ember app be aware of the network status? If yes: How can I get the information if the app has access to the internet or not? I'd like to switch GUI elements depending on the network accessibility.

index.html

<script type="text/x-handlebars">
  Status:
  {{#if isOffline}}
    Offline
  {{else}}
    Online
  {{/if}}
  <hr>

  {{outlet}}
</script>

<script type="text/x-handlebars" data-template-name="index">
  <h2>Hello World</h2>
</script>

app.js

App = Ember.Application.create();

回答1:

The short:

Since you asked for an ember app I've dedicated some time to provide an acceptable answer. Here is the working jsbin.

The long:

I add here some of the code, for the complete code please look at the jsbin provided.

index.html

<script type="text/x-handlebars">
  Status:
  {{#if App.isOffline}}
    <span class="offline">Offline</span>
  {{else}}
    <span class="online">Online</span>
  {{/if}}
  <hr>

  {{outlet}}
</script>

<script type="text/x-handlebars" data-template-name="index">
  <h2>Hello World</h2>
</script>

Note: I've used the js lib heyoffline.js since it's one of the best around IMO. I've also overriden the functions that show a modal window (the lib show's per default a modal window when offline occurs, but since we are going to control it trough our ember app it's not needed), to get it back just remove the prototype overiddes.

app.js

// overrides to not show the default modal window, to get it back just remove this overrides
Heyoffline.prototype.showMessage = function() {
  //this.createElements();
  if (this.options.onOnline) {
    return this.options.onOnline.call(this);
  }
};

Heyoffline.prototype.hideMessage = function(event) {
  if (event) {
    event.preventDefault();
  }
  //this.destroyElements();
  if (this.options.onOffline) {
    return this.options.onOffline.call(this);
  }
};


//ember app
var App = Ember.Application.create({
  isOffline: false,
  service: null,
  ready: function(){
    this.set('service', App.HeyOffline.create());
  }
});

// Heyoffline wrapper
App.HeyOffline = Ember.Object.extend({
  service: null,
  init: function(){
    // heyoffline instantiation
    this.set('service', new Heyoffline());
    // hook into the two important events
    this.set('service.options.onOnline', this.offline);
    this.set('service.options.onOffline', this.online);
  },
  online: function(){
    App.set('isOffline', false);
    console.log("online");
  },
  offline: function(){
    App.set('isOffline', true);
    console.log("offline");
  }
 });

 App.ApplicationRoute = Ember.Route.extend({});

To test that it works, load the jsbin and go offline, see how the Status in the template changes, go back online to see it change again.

With this setup in place you should get the online/offline status of the browser the ember way, enjoy :)

Hope it helps

回答2:

With HTML5, you can check the navigator.onLine boolean status.

if (navigator.onLine) {
    // Online
} else {
    // Offline
}

If you need to listen for going offline or online, you can handle the offline and online events of window. Note that in IE, the event is raised for document.body, not window.

References:

https://developer.mozilla.org/en-US/docs/DOM/window.navigator.onLine
https://developer.mozilla.org/en-US/docs/Online_and_offline_events

来源：https://stackoverflow.com/questions/16490059/display-online-and-offline-e-g-airplane-mode-in-an-ember-js-app

标签

javascript

ember.js