Timer control in flutter - flutter

Question

I'm trying to set one boolean false after 2 seconds(showSpinner) but can't handle it, main idea is showing loading spinner for 2 seconds after than showing solution but spinner never stops and solution never shows up(spinner is loading spinner, text = solution)
#override
void initState(){
super.initState();
showSpinner=true;
Timer(Duration(seconds: 2),(){
setState(() {
showSpinner=false;
});
});
}
Widget build(BuildContext context) {
Widget child;
if (showSpinner == true && isPressed4 == true) {
setState(() {
Timer(Duration(seconds: 2), () {
showSpinner == false;
});
});
child = spinkit;
}
if (showSpinner == false && isPressed4 == true) {
text = simpleInterest.accumulationFunction(
time, yearlySimpleInterestRate, principal);
child = Text(
text,
style: TextStyle(fontSize: 18),
textAlign: TextAlign.center,
);
}
there are 3 buttons(isPressed1 for button 1 and isPressed2 for button2 and isPressd3 for button 3, if all true isPressed4 becomes true)
var floatingActionButton1 = FloatingActionButton(
onPressed: () {
setState(() {
isPressed1 = !isPressed1;
});
setState(() {
principal = double.parse(_principalController.text);
});
setState(() {
if (isPressed3 == true && isPressed2 == true && isPressed1 == true) {
isPressed4 = true;
}
});
},
elevation: 40,
backgroundColor: isPressed1 ? Colors.lightGreenAccent : null,
heroTag: "btn1",
child: Icon(Icons.check),
);

Answer 1

I don't know what is spinkit and isPressed4, but I would do it like this:
bool showSpinner;
#override
void initState() {
super.initState();
showSpinner = true;
Timer(Duration(seconds: 2), () {
setState(() {
showSpinner = false;
});
});
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('Title'),
),
body: buildBody()
);
}
Widget buildBody(){
return showSpinner ?
CircularProgressIndicator() :
Text(
'The answer',
);
}
UPD:
Initially I have 2 seconds. Then:
If showSpinner == false and floatingActionButton1 has not been pressed, then I get text The time is up!.
If showSpinner == true and floatingActionButton1 has not been pressed, then I get text Button 4 is not pressed yet.
If showSpinner == true and floatingActionButton1 has been pressed, then I get CircularProgressIndicator()(as in the question).
If showSpinner == false and floatingActionButton1 has been pressed, then I get Text with The answer(as in the question):
bool showSpinner;
var floatingActionButton1;
bool isPressed1;
bool isPressed2;
bool isPressed3;
bool isPressed4;
#override
void initState() {
super.initState();
showSpinner = true;
isPressed1 = false;
isPressed2 = true;
isPressed3 = true;
isPressed4 = false;
floatingActionButton1 = FloatingActionButton(
onPressed: () {
setState(() {
isPressed1 = !isPressed1;
if (isPressed3 == true && isPressed2 == true && isPressed1 == true) {
isPressed4 = true;
}
});
},
backgroundColor: isPressed1 ? Colors.lightGreenAccent : null,
child: Icon(Icons.check),
);
Timer(Duration(seconds: 2), () {
setState(() {
showSpinner = false;
});
});
}
Widget build(BuildContext context) {
Widget child;
if(showSpinner == false && isPressed4 == false)
child = Text('The time is up!');
else if(showSpinner == true && isPressed4 == false)
child = Text('Button 4 is not pressed yet');
else if (showSpinner == true && isPressed4 == true) {
child = CircularProgressIndicator();
}
else if (showSpinner == false && isPressed4 == true) {
child = Text(
'The answer',
style: TextStyle(fontSize: 18),
textAlign: TextAlign.center,
);
}
return Scaffold(
appBar: AppBar(
title: Text('Title'),
),
body: child,
floatingActionButton: floatingActionButton1,
);
}

Answer 2

void startTimer() {
const oneSec = const Duration(seconds: 1);
_timer = new Timer.periodic(
oneSec,
(Timer timer) => setState(
() {
if (_start ==0) {
showSpinner=false;
timer.cancel();
} else {
_start = _start - 1;
}
},
),
);
}
#override
void dispose() {
_timer.cancel();
super.dispose();
}
solved with making this function and modifying buttons like;
var floatingActionButton1 = FloatingActionButton(
onPressed: () {
setState(() {
isPressed1 = !isPressed1;
});
setState(() {
principal = double.parse(_principalController.text);
});
setState(() {
if (isPressed3 == true && isPressed2 == true && isPressed1 == true) {
isPressed4 = true;
startTimer();
}
});
},
elevation: 40,
backgroundColor: isPressed1 ? Colors.lightGreenAccent : null,
heroTag: "btn1",
child: Icon(Icons.check),
);