Countdown timer date and time format in Flutter - flutter

Question

I'm making a Countdown timer, but the problem is, how can I make it realize the difference from AM to PM if it is a 24h clock? For instance, I have put the wakeUpTime inside the code to be tomorrow morning at 10. And if the time I'm asking this question is let's say 17:55h, I get a countdown to only 4 hours and 5min remaining, but it is supposed to say 16hours and 5min left. How can I achieve this? Here is the code below:
DateTime formatedDate = DateTime.parse(wakeUpTime);
int estimatedTimeLeft = formatedDate.millisecondsSinceEpoch; // needed date to countdown to
StreamBuilder(
stream: Stream.periodic(Duration(seconds: 1), (i) => i),
builder: (BuildContext context, AsyncSnapshot<int> snapshot) {
DateFormat format = DateFormat("hh:mm:ss");
int timeNow= DateTime
.now()
.millisecondsSinceEpoch;
Duration remaining = Duration(milliseconds: estimatedTimeLeft - timeNow);
var dateString = '${remaining.inHours}:${format.format(
DateTime.fromMillisecondsSinceEpoch(remaining.inMilliseconds))}';
print(dateString);
return Container(
child: Text(dateString),);
});
Did I format the Date and time wrong, or is it something else?
Thanks in advance for your help!

Answer 1

Below is a minimal code for testing, you can just copy and paste the code below, should work fine. Just input the endDate in DateTime format.
import 'dart:async';
import 'package:flutter/material.dart';
class DebugErrorClass extends StatefulWidget {
DebugErrorClass({
Key? key,
}) : super(key: key);
#override
_DebugErrorClassState createState() => _DebugErrorClassState();
}
class _DebugErrorClassState extends State<DebugErrorClass> {
String remainingTime = "";
Timer? _timer;
StreamController<String> timerStream = StreamController<String>.broadcast();
final endDate = DateTime.now().add(Duration(days: 5)); // the date, time u set
final currentDate = DateTime.now();
#override
void initState() {
prepareData();
super.initState();
}
#override
void dispose() {
try{
if (_timer != null && _timer!.isActive) _timer!.cancel();
}catch(e){
print(e);
}
super.dispose();
}
prepareData(){
final difference = daysBetween(currentDate, endDate);
print(difference);
print('difference in days');
// get remaining time in second
var result = Duration(seconds: 0);
result = endDate.difference(currentDate);
remainingTime = result.inSeconds.toString(); // convert to second
// remainingTime = '10'; // change this value to test for min function
}
int daysBetween(DateTime from, DateTime to) {
from = DateTime(from.year, from.month, from.day);
to = DateTime(to.year, to.month, to.day);
return (to.difference(from).inHours / 24).round();
}
String dayHourMinuteSecondFunction(Duration duration) {
String twoDigits(int n) => n.toString().padLeft(2, "0");
String days = twoDigits(duration.inDays);
String twoDigitHours = twoDigits(duration.inHours.remainder(24));
String twoDigitMinutes = twoDigits(duration.inMinutes.remainder(60));
String twoDigitSeconds = twoDigits(duration.inSeconds.remainder(60));
return days+' '+"Days"+' '+twoDigitHours+' '+"Hours"+' '+twoDigitMinutes+' '+"Minutes"+' '+twoDigitSeconds+"Seconds";
}
Widget dateWidget(){
return StreamBuilder<String>(
stream: timerStream.stream,
initialData: "0",
builder: (cxt, snapshot) {
const oneSec = Duration(seconds: 1);
if (_timer != null && _timer!.isActive) _timer!.cancel();
_timer = Timer.periodic(oneSec, (Timer timer) {
try {
int second = int.tryParse(remainingTime)?? 0;
second = second - 1;
if (second < -1) return;
remainingTime = second.toString();
if (second == -1) {
timer.cancel();
print('timer cancelled');
}
if(second >= 0){
timerStream.add(remainingTime);
}
} catch (e) {
print(e);
}
});
String remainTimeDisplay = "-";
try {
int seconds = int.parse(remainingTime);
var now = Duration(seconds: seconds);
remainTimeDisplay = dayHourMinuteSecondFunction(now);
} catch (e) {
print(e);
}
print(remainTimeDisplay);
return Text(remainTimeDisplay, textAlign: TextAlign.center,);
});
}
#override
Widget build(BuildContext context) {
return Scaffold(
body: SafeArea(
child: Container(
alignment: Alignment.center,
width: double.infinity,
height: double.infinity,
child: SingleChildScrollView(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
crossAxisAlignment: CrossAxisAlignment.center,
children: [
dateWidget(),
],
),
),
),
),
);
}
}