public void onExtraButtonClick(final View view) {
		final Context context = view.getContext();
		if (action_extra == R.string.button_instructions_online) {
			WebContent.view(context, Config.URL_SETUP.get());
		} else if (action_extra == R.string.button_account_settings) {
			Activities.startActivity(context, new Intent(Settings.ACTION_SYNC_SETTINGS));
			if (context instanceof Activity) ((Activity) context).finish();
		} else if (action_extra == R.string.button_have_checked) {
			button_next.set(0);
			mIncompleteSetupAcked = true;
			view.setVisibility(View.GONE);
		} else if (action_extra == R.string.button_setup_island_with_root) {
			IslandSetup.requestProfileOwnerSetupWithRoot(Activities.findActivityFrom(context));
		} else throw new IllegalStateException();
	}
@return null if all prerequisites met TODO: Move this method to IslandSetup
mobile/src/main/java/com/oasisfeng/island/setup/SetupViewModel.java