Ember.js accessing and changing variables between controllers - ember.js

Question

I am attempting to write a login/logout widget with ember. I want to toggle the isLoggedIn property such that when a user logs out it is set to False and, True when a user logs in. isLoggedIn is defined in my application controller and called with handlebars in my application template. For now, I need to set the value of of isLoggedIn to true when a user logs in successfully and the Login function is activated inside of LoginController - and logout when the user clicks logout. So my question is: how can I have LoginController & application controller access each other and change variables within them.
Here is some code from the application template:
<section class="top-bar-section">
<!-- Right Nav Section -->
<ul class="right">
...
{{#if isLoggedIn}}
<li><a href="#" {{ action "logout" }}>Logout</a></li>
{{else}}
<li>
{{#linkTo "login"}}Login{{/linkTo}} </li>
{{/if}}
</ul>
</section>
</nav>
{{outlet}}
application controller:
var App;
App = require('app');
module.exports = App.ApplicationController = Ember.ObjectController.extend({
isLoggedIn: false,
logout: function(){
this.set("isLoggedIn", false);
console.log(this.token);
}
});
login template:
...
<form class="form-horizontal" {{action "login" on="submit"}}>
...
<div class="row">
<div class="large-5 columns">
<label>Username</label>
{{input value=username type="text" placeholder="Username"}}
</div>
<div class="large-5 columns">
<label>Password</label>
{{input value=password type="password" placeholder="Password"}}
</div>
<div class="large-2 columns">
</br>
{{input class="small button" type="submit" value="Log In"}}
</div>
</div>
</form>
{{#if errorMessage}}
<div class="large-12 columns alert-box alert">{{errorMessage}}</div>
{{/if}}
{{/if}}
LoginController:
var App;
App = require('app');
module.exports = App.LoginController = Ember.ObjectController.extend({
//some variables...
//other functions...
login: function() {
// set isLoggedIn to true here
...}
});
initially the navbar will see that isLoggedIn is false and therefore show Login. Once you successfully login and click submit, an action will fire off and activate login() inside of LoginController. That is where I want to set isLoggedIn to true such that Logout will appear on the navbar.

Answer 1

Have you tried:
module.exports = App.LoginController = Ember.ObjectController.extend({
needs: ['application']
login: function() {
if (authentification sucess) {
this.set('controllers.application.isLoggedIn', true);
} else {
this.set('controllers.application.isLoggedIn', false);
}
}
});
To access other controllers instances, you use the needs property. Each specified controller will be injected in the controllers property. So needs: ['application'], injects the application controller in controllers.applicaiton.