How to access Laravel Singletons in a class?

Question

I have registered a singleton in a service provider like so:

$this->app->singleton(MyClass::class);

This can normally be accessed by simply stating it in the parameters like so:

class FooController extends Controller
{
    public function index(MyClass $myClass)
    {
        //...
    }
}

However I cannot seem to be able to access this singleton in other custom classes (i.e. non controller classes). (https://laravel.com/docs/5.2/container#resolving)

For example like here:

class Bar {
   private $myClass;
   private $a;
   private $b;

   public function __construct($a, $b) {
      $this->a = $a;
      $this->b = $b;
      $this->myClass = ... // TODO: get singleton
   }
}

How do I do this?

Note that I will be creating multiple instances of Bar.

Answer 1

In later Laravel versions 6 and higher there are even more helpers to solve this:

resolve(MyClass::class);
app(MyClass::class);

& all the methods provided by the other answers

class Bar {
   private $myClass;
   private $a;
   private $b;

   public function __construct($a, $b) {
      $this->a = $a;
      $this->b = $b;
      $this->myClass = app(MyClass::class);
   }
}