Singleton in Android

Tip: To create singleton class In Android Studio, right click in your project and open menu:

New -> Java Class -> Choose Singleton from dropdown menu

EDIT :

The implementation of a Singleton in Android is not "safe" (see here) and you should use a library dedicated to this kind of pattern like Dagger or other DI library to manage the lifecycle and the injection.

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Could you post an example from your code ?

Take a look at this gist : https://gist.github.com/Akayh/5566992

it works but it was done very quickly :

MyActivity : set the singleton for the first time + initialize mString attribute ("Hello") in private constructor and show the value ("Hello")

Set new value to mString : "Singleton"

Launch activityB and show the mString value. "Singleton" appears...