flutter 实现时间流失效果

使用 flutter 进度条组件和 RotatedBox 旋转组件，实现时间流失进度条

进度条组件LinearProgressIndicator

属性说明：

value  0-1 之间 进度

RotatedBox 组件

quarterTurns 属性表示象限

quarterTurns: 0 水平

quarterTurns: 1  顺时针旋转 90 度(quarterTurns = 1)

quarterTurns: -1 逆时针旋转 90 度(quarterTurns = -1)。

代码实现

library flutter_timer_countdown;
import 'dart:async';
import 'package:LS/common/global.dart';
import 'package:flutter/widgets.dart';
import 'package:get/get.dart';
enum CountDownTimerFormat {
  daysHoursMinutesSeconds,
  daysHoursMinutes,
  daysHours,
  daysOnly,
  hoursMinutesSeconds,
  hoursMinutes,
  hoursOnly,
  minutesSeconds,
  minutesOnly,
  secondsOnly,
}
typedef OnTickCallBack = void Function(Duration remainingTime);
class TimerCountdown extends StatefulWidget {
  /// Format for the timer coundtown, choose between different `CountDownTimerFormat`s
  final CountDownTimerFormat format;
  /// Defines the time when the timer is over.
  final DateTime endTime;
  /// Gives you remaining time after every tick.
  final OnTickCallBack? onTick;
  /// Function to call when the timer is over.
  final VoidCallback? onEnd;
  /// Toggle time units descriptions.
  final bool enableDescriptions;
  /// `TextStyle` for the time numbers.
  final TextStyle? timeTextStyle;
  /// `TextStyle` for the colons betwenn the time numbers.
  final TextStyle? colonsTextStyle;
  /// `TextStyle` for the description
  final TextStyle? descriptionTextStyle;
  /// Days unit description.
  final String daysDescription;
  /// Hours unit description.
  final String hoursDescription;
  /// Minutes unit description.
  final String minutesDescription;
  /// Seconds unit description.
  final String secondsDescription;
  /// Defines the width between the colons and the units.
  final double spacerWidth;
  final Widget? rightWidget;
  // 结束的 组件
  final Widget? endWidget;
  const TimerCountdown({
    required this.endTime,
    this.format = CountDownTimerFormat.daysHoursMinutesSeconds,
    this.enableDescriptions = true,
    this.onEnd,
    this.timeTextStyle,
    this.onTick,
    this.colonsTextStyle,
    this.descriptionTextStyle,
    this.daysDescription = "Days",
    this.hoursDescription = "Hours",
    this.minutesDescription = "Minutes",
    this.secondsDescription = "Seconds",
    this.spacerWidth = 10,
    this.rightWidget,
    this.endWidget,
  });
  @override
  _TimerCountdownState createState() => _TimerCountdownState();
}
class _TimerCountdownState extends State {
  bool isEnd = false;
  Timer? timer;
  late String countdownDays;
  late String countdownHours;
  late String countdownMinutes;
  late String countdownSeconds;
  late Duration difference;
  @override
  void initState() {
    _startTimer();
    super.initState();
  }
  @override
  void dispose() {
    if (timer != null) {
      timer!.cancel();
    }
    super.dispose();
  }
  /// Calculate the time difference between now end the given [endTime] and initialize all UI timer values.
  ///
  /// Then create a periodic `Timer` which updates all fields every second depending on the time difference which is getting smaller.
  /// When this difference reached `Duration.zero` the `Timer` is stopped and the [onEnd] callback is invoked.
  void _startTimer() {
    if (widget.endTime.isBefore(Global.serverTime)) {
      difference = Duration.zero;
    } else {
      difference = widget.endTime.difference(Global.serverTime);
    }
    countdownDays = _durationToStringDays(difference);
    countdownHours = _durationToStringHours(difference);
    countdownMinutes = _durationToStringMinutes(difference);
    countdownSeconds = _durationToStringSeconds(difference);
    if (difference == Duration.zero) {
      if (widget.onEnd != null) {
        widget.onEnd!();
      }
      setState(() {
        isEnd = true;
      });
    } else {
      timer = Timer.periodic(const Duration(seconds: 1), (timer) {
        difference = widget.endTime.difference(Global.serverTime);
        widget.onTick?.call(difference);
        setState(() {
          countdownDays = _durationToStringDays(difference);
          countdownHours = _durationToStringHours(difference);
          countdownMinutes = _durationToStringMinutes(difference);
          countdownSeconds = _durationToStringSeconds(difference);
        });
        if (difference <= Duration.zero) {
          timer.cancel();
          if (widget.onEnd != null) {
            widget.onEnd!();
          }
          setState(() {
            isEnd = true;
          });
        }
      });
    }
  }
  @override
  Widget build(BuildContext context) {
    return Wrap(
      children: [
        if (widget.rightWidget != null && !isEnd) widget.rightWidget as Widget,
        _countDownTimerFormat(),
      ],
    );
  }
  /// Builds the UI colons between the time units.
  Widget _colon({String unit = ":"}) {
    return Row(
      children: [
        SizedBox(
          width: widget.spacerWidth,
        ),
        Column(
          mainAxisSize: MainAxisSize.min,
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            Text(
              unit.tr,
              style: widget.colonsTextStyle,
            ),
            if (widget.enableDescriptions)
              const SizedBox(
                height: 5,
              ),
            if (widget.enableDescriptions)
              Text(
                "",
                style: widget.descriptionTextStyle,
              ),
          ],
        ),
        SizedBox(
          width: widget.spacerWidth,
        ),
      ],
    );
  }
  /// Builds the timer days with its description.
  Widget _days(BuildContext context) {
    return Column(
      mainAxisSize: MainAxisSize.min,
      crossAxisAlignment: CrossAxisAlignment.center,
      children: [
        Text(
          countdownDays.tr,
          style: widget.timeTextStyle,
        ),
        if (widget.enableDescriptions) const SizedBox(height: 5),
        if (widget.enableDescriptions)
          Text(
            widget.daysDescription.tr,
            style: widget.descriptionTextStyle,
          ),
      ],
    );
  }
  /// Builds the timer hours with its description.
  Widget _hours(BuildContext context) {
    return Column(
      mainAxisSize: MainAxisSize.min,
      crossAxisAlignment: CrossAxisAlignment.center,
      children: [
        Text(
          countdownHours.tr,
          style: widget.timeTextStyle,
        ),
        if (widget.enableDescriptions) const SizedBox(height: 5),
        if (widget.enableDescriptions)
          Text(
            widget.hoursDescription.tr,
            style: widget.descriptionTextStyle,
          ),
      ],
    );
  }
  /// Builds the timer minutes with its description.
  Widget _minutes(BuildContext context) {
    return Column(
      mainAxisSize: MainAxisSize.min,
      crossAxisAlignment: CrossAxisAlignment.center,
      children: [
        Text(
          countdownMinutes.tr,
          style: widget.timeTextStyle,
        ),
        if (widget.enableDescriptions) const SizedBox(height: 5),
        if (widget.enableDescriptions)
          Text(
            widget.minutesDescription.tr,
            style: widget.descriptionTextStyle,
          ),
      ],
    );
  }
  /// Builds the timer seconds with its description.
  Widget _seconds(BuildContext context) {
    return Column(
      crossAxisAlignment: CrossAxisAlignment.center,
      mainAxisSize: MainAxisSize.min,
      children: [
        Text(
          countdownSeconds.tr,
          style: widget.timeTextStyle,
        ),
        if (widget.enableDescriptions) const SizedBox(height: 5),
        if (widget.enableDescriptions)
          Text(
            widget.secondsDescription.tr,
            style: widget.descriptionTextStyle,
          ),
      ],
    );
  }
  /// When the selected [CountDownTimerFormat] is leaving out the last unit, this function puts the UI value of the unit before up by one.
  ///
  /// This is done to show the currently running time unit.
  String _twoDigits(int n, String unitType) {
    switch (unitType) {
      case "minutes":
        if (widget.format == CountDownTimerFormat.daysHoursMinutes ||
            widget.format == CountDownTimerFormat.hoursMinutes ||
            widget.format == CountDownTimerFormat.minutesOnly) {
          if (difference > Duration.zero) {
            n++;
          }
        }
        if (n >= 10) return "$n";
        return "0$n";
      case "hours":
        if (widget.format == CountDownTimerFormat.daysHours ||
            widget.format == CountDownTimerFormat.hoursOnly) {
          if (difference > Duration.zero) {
            n++;
          }
        }
        if (n >= 10) return "$n";
        return "0$n";
      case "days":
        if (widget.format == CountDownTimerFormat.daysOnly) {
          if (difference > Duration.zero) {
            n++;
          }
        }
        if (n >= 10) return "$n";
        return "0$n";
      default:
        if (n >= 10) return "$n";
        return "0$n";
    }
  }
  /// Convert [Duration] in days to String for UI.
  String _durationToStringDays(Duration duration) {
    return _twoDigits(duration.inDays, "days").toString();
  }
  /// Convert [Duration] in hours to String for UI.
  String _durationToStringHours(Duration duration) {
    if (widget.format == CountDownTimerFormat.hoursMinutesSeconds ||
        widget.format == CountDownTimerFormat.hoursMinutes ||
        widget.format == CountDownTimerFormat.hoursOnly) {
      return _twoDigits(duration.inHours, "hours");
    } else
      return _twoDigits(duration.inHours.remainder(24), "hours").toString();
  }
  /// Convert [Duration] in minutes to String for UI.
  String _durationToStringMinutes(Duration duration) {
    if (widget.format == CountDownTimerFormat.minutesSeconds ||
        widget.format == CountDownTimerFormat.minutesOnly) {
      return _twoDigits(duration.inMinutes, "minutes");
    } else
      return _twoDigits(duration.inMinutes.remainder(60), "minutes");
  }
  /// Convert [Duration] in seconds to String for UI.
  String _durationToStringSeconds(Duration duration) {
    if (widget.format == CountDownTimerFormat.secondsOnly) {
      return _twoDigits(duration.inSeconds, "seconds");
    } else
      return _twoDigits(duration.inSeconds.remainder(60), "seconds");
  }
  /// Switches the UI to be displayed based on [CountDownTimerFormat].
  Widget _countDownTimerFormat() {
    if (isEnd) {
      return widget.endWidget == null
          ? Container()
          : widget.endWidget as Widget;
    }
    switch (widget.format) {
      case CountDownTimerFormat.daysHoursMinutesSeconds:
        return Row(
          mainAxisSize: MainAxisSize.min,
          children: [
            _days(context),
            _colon(unit: "天"),
            _hours(context),
            _colon(unit: ":"),
            _minutes(context),
            _colon(unit: ":"),
            _seconds(context),
            // Text(":".tr, style: widget.colonsTextStyle),
          ],
        );
      case CountDownTimerFormat.daysHoursMinutes:
        return Row(
          mainAxisSize: MainAxisSize.min,
          children: [
            _days(context),
            _colon(unit: "天"),
            _hours(context),
            _colon(unit: ":"),
            _minutes(context),
          ],
        );
      case CountDownTimerFormat.daysHours:
        return Row(
          mainAxisSize: MainAxisSize.min,
          children: [
            _days(context),
            _colon(unit: "天"),
            _hours(context),
          ],
        );
      case CountDownTimerFormat.daysOnly:
        return Row(
          mainAxisSize: MainAxisSize.min,
          children: [
            _days(context),
          ],
        );
      case CountDownTimerFormat.hoursMinutesSeconds:
        return Row(
          mainAxisSize: MainAxisSize.min,
          children: [
            _hours(context),
            _colon(unit: ":"),
            _minutes(context),
            _colon(unit: ":"),
            _seconds(context),
            // Text(":".tr, style: widget.colonsTextStyle),
          ],
        );
      case CountDownTimerFormat.hoursMinutes:
        return Row(
          mainAxisSize: MainAxisSize.min,
          children: [
            _hours(context),
            _colon(unit: ":"),
            _minutes(context),
          ],
        );
      case CountDownTimerFormat.hoursOnly:
        return Row(
          mainAxisSize: MainAxisSize.min,
          children: [
            _hours(context),
          ],
        );
      case CountDownTimerFormat.minutesSeconds:
        return Row(
          mainAxisSize: MainAxisSize.min,
          children: [
            _minutes(context),
            _colon(unit: ":"),
            _seconds(context),
          ],
        );
      case CountDownTimerFormat.minutesOnly:
        return Row(
          mainAxisSize: MainAxisSize.min,
          children: [
            _minutes(context),
          ],
        );
      case CountDownTimerFormat.secondsOnly:
        return Row(
          mainAxisSize: MainAxisSize.min,
          children: [
            _seconds(context),
          ],
        );
      default:
        return Row(
          mainAxisSize: MainAxisSize.min,
          children: [
            _days(context),
            _colon(unit: "天"),
            _hours(context),
            _colon(unit: ":"),
            _minutes(context),
            _colon(unit: ":"),
            _seconds(context),
          ],
        );
    }
  }
}