How to make a stopwatch that takes a widget off the air? - flutter

Question

I need to know how to make this stopwatch, which after 48 hours disables a widget, which in my case is a button. Can someone explain to me how to do it? What classes to use?
I tried to use this, but don't works:
var timer = Timer(Duration(seconds: 1), () => print('done'));

Answer 1

it seems to me that you want this button to be disabled after 2 days of the app that was installed, you need persist the date on the device so that after app-restarts the date will be itself, you need to use a package the persists the data on the device. i recommend shared_preference which is easy to use.
for your case, in the screen where you use the button you need to do this
import 'package:shared_preferences/shared_preferences.dart';
class MyFirstStatefullScreen extends StatefullWidget {
MyFirstStatefullScreenState createState() => MyFirstStatefullScreenState();
}
class MyFirstStatefullScreenState extends State<MyFirstStatefullScreen>{
// some other code that u wrote
bool shouldButtonBeActive = true;
#override
void initState() {
Future.delayed(Duration(0))
.then((_) {
SharedPreferences sharedPrefs= await SharedPreferences.getInstance();
final deadLine = sharedPrefs.getString('deadLine');
if(deadLine == null) {
// this is the first time the app has been installed on the device
// so we need to set the deadLine to N number of days after the installation
final deadLineDate = DateTime.now().add(Duration(days: 2)); // 2 days from the date that the app was installed;
sharedPrefs.setString(deadLineDate.toIso8601String()); // set it so we can check on the successfull state
return;
}
final deadLineDate = DateTime.parse(deadLine); // since we stored it as a string;
/// the deadline is set and is not null
if(DateTime.now().compareTo(deadLineDate) == 0) {
we are successfull, N hours have passed since the intial instalation, now we can disable the button
shouldButtonBeActive = false; // the button should be disabled
}
})
}
Widget build(context) {
// in your UI where you use the button
MaterialButton(
child: Text("Button"),
onPressed: shouldButtonBeActive ? func() : null
)
}
}
PS: we are using the Future inside the initState, because initState dose not allow async ( api calls, storage access) in it.