Disable a whole activity from user action

Question

Is there a simple way to disable a user interacting with an activity. To be done when there is an action running (and a spinning progress bar in the title bar)

EDIT:

Answer 1

The code of Uriel Frankel (accepted response), works good, but in my case works after my request it's done :(. I want to block before it happend. Some one knows what is wrong in my code (I'm beginning in this..)

(this is a fragment)

   login_login_btn.setOnClickListener {

    if (validateInputs()){
        showSpinner()
        thread {
            doLogin()
        }
    } else {
        validationError("Validation Error","Checkout your inputs. Common errors: \npassword (at least 8 characters)")
    }

}

}

Function after OnViewCreated

fun showSpinner(){
    activity?.window?.setFlags(
        WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE,
        WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE)
    spinner.visibility = View.VISIBLE
}

Thank you (Y)