Dart - Create a countdown timer that prints a remaining time every 5 seconds for each value in a list

To create a countdown timer in Dart that prints remaining time every 5 seconds for each value in a list, you can use Dart's Timer class and Duration to manage time-based operations. Here's a step-by-step guide to achieve this:

Example Code

import 'dart:async'; void main() { List<int> countdownValues = [10, 20, 30]; // Example countdown values for (var value in countdownValues) { startCountdown(value); } } void startCountdown(int seconds) { int remainingTime = seconds; // Create a timer that runs every 1 second Timer timer = Timer.periodic(Duration(seconds: 1), (Timer t) { remainingTime--; // Print remaining time every 5 seconds if (remainingTime % 5 == 0) { print('Remaining time for $seconds seconds: $remainingTime seconds'); } // Check if countdown is complete if (remainingTime <= 0) { t.cancel(); // Cancel the timer when countdown is complete print('Countdown for $seconds seconds is complete'); } }); }

Explanation:

Main Function:
- Initializes a list countdownValues with example countdown durations in seconds (10, 20, 30).
startCountdown Function:
- Takes an integer parameter seconds representing the initial countdown duration.
- Initializes remainingTime with the countdown duration.
- Creates a periodic timer (Timer.periodic) that runs every second (Duration(seconds: 1)).
Timer Callback:
- Decrements remainingTime by one every second.
- Checks if the current remainingTime is divisible by 5 (remainingTime % 5 == 0), and prints the remaining time. This happens every 5 seconds.
- Checks if remainingTime is less than or equal to 0, cancels the timer (t.cancel()), and prints a completion message.
Output:
- Prints the remaining time every 5 seconds until the countdown completes for each value in countdownValues.

Notes:

Adjust countdownValues to contain any list of integers representing different countdown durations.
Ensure to handle edge cases or specific requirements (like formatting output) based on your application needs.
For Flutter applications, consider using StatefulWidget and updating the UI using setState() to reflect countdown changes visually.

This Dart code provides a basic framework for creating and managing countdown timers that print remaining time every 5 seconds for each value in a list. Customize and extend it according to your specific application requirements and UI framework.

Examples

1. How to Create a Countdown Timer in Dart

Description: Learn how to create a basic countdown timer in Dart that prints the remaining time every 5 seconds.

import 'dart:async'; void countdown(int seconds) { Timer.periodic(Duration(seconds: 5), (timer) { seconds -= 5; if (seconds <= 0) { print('Time\'s up!'); timer.cancel(); } else { print('Remaining time: $seconds seconds'); } }); } void main() { countdown(30); }

2. Dart Timer.periodic Example for Countdown

Description: Use Dart's Timer.periodic to create a countdown timer that prints every 5 seconds.

import 'dart:async'; void countdown(List<int> times) { for (var time in times) { Timer.periodic(Duration(seconds: 5), (timer) { time -= 5; if (time <= 0) { print('Time\'s up!'); timer.cancel(); } else { print('Remaining time: $time seconds'); } }); } } void main() { countdown([30, 60, 90]); }

3. Countdown Timer for Each Value in a List in Dart

Description: Implement a countdown timer for each value in a list and print the remaining time every 5 seconds.

import 'dart:async'; void countdown(List<int> times) { times.forEach((time) { Timer.periodic(Duration(seconds: 5), (timer) { time -= 5; if (time <= 0) { print('Time\'s up!'); timer.cancel(); } else { print('Remaining time: $time seconds'); } }); }); } void main() { countdown([20, 40, 60]); }

4. Using Dart Timer to Print Remaining Time

Description: Use Dart's Timer to print the remaining time of a countdown every 5 seconds.

import 'dart:async'; void countdown(int seconds) { Timer.periodic(Duration(seconds: 5), (timer) { seconds -= 5; if (seconds <= 0) { print('Countdown finished!'); timer.cancel(); } else { print('Remaining time: $seconds seconds'); } }); } void main() { countdown(50); }

5. Dart Timer for Multiple Countdown Timers

Description: Implement multiple countdown timers in Dart using Timer and print the remaining time every 5 seconds for each.

import 'dart:async'; void countdown(List<int> times) { times.forEach((time) { Timer.periodic(Duration(seconds: 5), (timer) { time -= 5; if (time <= 0) { print('Timer done!'); timer.cancel(); } else { print('Remaining time: $time seconds'); } }); }); } void main() { countdown([25, 50, 75]); }

6. Creating Multiple Countdown Timers in Dart

Description: Learn to create multiple countdown timers that run concurrently and print the remaining time every 5 seconds.

import 'dart:async'; void countdown(List<int> times) { for (var time in times) { Timer.periodic(Duration(seconds: 5), (timer) { time -= 5; if (time <= 0) { print('Timer finished!'); timer.cancel(); } else { print('Remaining time: $time seconds'); } }); } } void main() { countdown([15, 30, 45]); }

7. Dart Timer with List of Countdown Values

Description: Implement a countdown timer for each value in a list using Dart's Timer and print the remaining time every 5 seconds.

import 'dart:async'; void countdown(List<int> times) { times.forEach((time) { Timer.periodic(Duration(seconds: 5), (timer) { time -= 5; if (time <= 0) { print('Finished!'); timer.cancel(); } else { print('Remaining time: $time seconds'); } }); }); } void main() { countdown([10, 20, 30]); }

8. Dart Periodic Timer for Countdown Timers

Description: Utilize Dart's periodic timer to create countdown timers for a list of values and print the remaining time every 5 seconds.

import 'dart:async'; void countdown(List<int> times) { times.forEach((time) { Timer.periodic(Duration(seconds: 5), (timer) { time -= 5; if (time <= 0) { print('Time\'s up!'); timer.cancel(); } else { print('Remaining time: $time seconds'); } }); }); } void main() { countdown([50, 100, 150]); }

9. Implementing Concurrent Countdown Timers in Dart

Description: Implement concurrent countdown timers using Dart and print the remaining time every 5 seconds.

import 'dart:async'; void countdown(List<int> times) { times.forEach((time) { Timer.periodic(Duration(seconds: 5), (timer) { time -= 5; if (time <= 0) { print('Timer ended!'); timer.cancel(); } else { print('Remaining time: $time seconds'); } }); }); } void main() { countdown([60, 120, 180]); }

10. Dart Countdown Timer with Periodic Print

Description: Create a countdown timer in Dart that prints the remaining time every 5 seconds for each value in a list.

import 'dart:async'; void countdown(List<int> times) { for (var time in times) { Timer.periodic(Duration(seconds: 5), (timer) { time -= 5; if (time <= 0) { print('Countdown complete!'); timer.cancel(); } else { print('Remaining time: $time seconds'); } }); } } void main() { countdown([5, 10, 15]); }

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