How do I make Flutter Widget disappear after certain time (in days)? - flutter

Question

I have few widgets on home screen, one of them is there only if user save some data, from that moment
I want to count 7 days and if nothing else happen widget will be deleted.
I tried something like this:
//When user save data to widget
_saveTime() async {
SharedPreferences pref = await SharedPreferences.getInstance();
pref.setString(
'StoreTime', DateTime.now().add(Duration(days: 8)).toString());
}
Then in the Home page
...
bool _thirdMenu;
String _difDays = '';
#override
initState() {
super.initState();
_thirdMenu = true;
WidgetsBinding.instance.addObserver(this);
_init();
}
_init() async {
SharedPreferences pref = await SharedPreferences.getInstance();
String oldTimePref = pref.getString('StoreTime') ?? '1969-07-20 20:18:04Z';
DateTime oldTime = DateTime.parse(oldTimePref);
DateTime newTime = DateTime.now();
var difference = oldTime.difference(newTime);
if (difference.inDays > 0) {
setState(() {
_thirdMenu = true;
_difDays = difference.inDays.toString();
});
} else {
setState(() {
_thirdMenu = false;
});
}
}
Not working, time stay the same and widget still showing...

Answer 1

If you want to work with days, I think you can work without hours and minutes.
You can isolate the days and check without using time difference.
int oldDay = oldTime.day;
int today = newTime.day;
if(today - oldDay >= 7) {
setState(() {
_thirdMenu = false;
});
} else {
setState(() {
_thirdMenu = true;
});
}