static @Nullable Integer getResConfigMaxUsers() {
		final Resources sys_res = Resources.getSystem();
		final int res = sys_res.getIdentifier(RES_MAX_USERS, "integer", "android");
		if (res == 0) return null;
		return Resources.getSystem().getInteger(res);
	}
Implementation of Island / Mainland setup & shutdown.

Created by Oasis on 2017/3/8.
mobile/src/main/java/com/oasisfeng/island/setup/IslandSetup.java