onClick handler for an authentication event

MainActivity.kt

fun onLockClicked(caller: View) {
  Log.d(TAG, "Lock clicked - caller=${caller.id}")
  if (AWSProvider.identityManager.isUserSignedIn) {
    AWSProvider.identityManager.signOut()
    mainToolbarLockIcon.setImageResource(R.drawable.ic_unlocked_24dp)
    this.toast("Signed out of Amazon Cognito")
  } else {
    val intent = Intent(this, AuthenticatorActivity::class.java)
    startActivity(intent)
  }
}