How to create singleton in flutter?

In Flutter, you can create a singleton using the `factory` constructor. Here's an example implementation:

class MySingleton {

  static final MySingleton _singleton = MySingleton._internal();


  factory MySingleton() {

    return _singleton;

  }


  MySingleton._internal();

  void doSomething() {

    print("Singleton method called");

  }

}
        

In this implementation, the `MySingleton` class has a private constructor `_internal()` that is called by the factory constructor. The `_singleton` static variable is of type `MySingleton` and stores a single instance of the `MySingleton` class.

To create and use the singleton instance, you can simply call the factory constructor:

var mySingleton = MySingleton();

mySingleton.doSomething(); // Outputs "Singleton method called"        

Note that you cannot create a new instance of the `MySingleton` class using the `new` keyword, because the constructor is private.