How to declare global variables in Android?

Question

I am creating an application which requires login. I created the main and the login activity.

In the main activity onCreate method I added the following

Answer 1

You can have a static field to store this kind of state. Or put it to the resource Bundle and restore from there on onCreate(Bundle savedInstanceState). Just make sure you entirely understand Android app managed lifecycle (e.g. why login() gets called on keyboard orientation change).