颤振可编程定时器

Question

我想为我的学校项目建立婚礼应用程序。我不能建一个可编程的计时器。用户应将计时器设置为"10周后“，计时器开始倒计时至9周、23小时等。对如何实现我的目标有什么建议吗？

Answer 1

要完成这项任务，您应该遵循以下几个步骤：

1. 您必须让用户选择日期和/或时间。
2. 您必须计算剩余的字符串(x年、x月、x天等)。
3. 将其显示给用户。
4. 开始一个计时器，这将更新UI。

//Timer

Timer.periodic(const Duration(seconds: 1), (timer) {
  //every 1 second, the state will be updated
  setState(() {});
});

//remainingTime calculator
//you have to put this string to a Text widget
String get  _calculateRemainingTime{
    Duration remainingDuration = widget.date.difference(DateTime.now());

    if(remainingDuration.inSeconds <= 0){
      return 'Time has come';
    }

    int remainingSeconds = remainingDuration.inSeconds % 60;

    int remainingMinutes = remainingDuration.inMinutes % 60;

    int remainingHours = remainingDuration.inHours % 24;

    int remainingDays = remainingDuration.inDays;

    int remainingMonths = remainingDays ~/ 30;

    int remainingYears = remainingMonths ~/ 12;

    remainingDays = remainingDays % 30;

    remainingMonths = remainingMonths % 12;


    return '${remainingYears != 0 ? remainingYears.toString() + ' years' : ''} ${remainingMonths != 0 ? remainingMonths.toString() + ' months' : ''} ${remainingDays != 0 ? remainingDays.toString() + ' days' : ''} ${remainingHours != 0 ? remainingHours.toString() + ' hours' : ''} ${remainingMinutes != 0 ? remainingMinutes.toString() + ' minutes' : ''} ${remainingSeconds != 0 ? remainingSeconds.toString() + ' seconds' : ''}';
  }

我在github页面上有一个示例：颤振定时器示例

如果你需要进一步的帮助，告诉我。