eitc_erm_dental_flutter/lib/widget/count_down_text.dart

import 'dart:async';

import 'package:flutter/material.dart';

///倒计时文本
class CountDownText extends StatefulWidget {
  final TextStyle? textStyle;
  final CountDownTextController controller;

  const CountDownText({super.key, required this.controller, this.textStyle});

  @override
  State<CountDownText> createState() => _CountDownTextState();
}

class _CountDownTextState extends State<CountDownText> {
  @override
  void initState() {
    super.initState();
    widget.controller.countText.addListener(_onUpdateCountText);
  }

  void _onUpdateCountText() {
    setState(() {});
  }

  @override
  void dispose() {
    super.dispose();
    widget.controller.countText.removeListener(_onUpdateCountText);
    widget.controller.stopCount();
  }

  @override
  Widget build(BuildContext context) {
    return Text(
      widget.controller.countText.value,
      style: widget.textStyle,
    );
  }
}

class CountDownTextController {
  ValueNotifier<String>? _countText;

  ValueNotifier<String> get countText => _countText ??= ValueNotifier("");

  void Function(int tick, bool complete)? onCount;

  Timer? _countTimer;

  CountDownTextController(this.onCount);

  bool get isCounting => _countTimer != null;

  void startCount(int time) {
    if (isCounting) {
      return;
    }
    if (time <= 0) {
      onCount?.call(0, true);
      return;
    }
    _countTimer = Timer.periodic(const Duration(seconds: 1), (tick) {
      int left = time - tick.tick;
      bool compelte = left <= 0;
      if (compelte) {
        _timeUp();
      } else {
        countText.value = "$left";
      }
      onCount?.call(tick.tick, compelte);
    });
    countText.value = "$time";
  }

  void stopCount() {
    _countTimer?.cancel();
    _countTimer = null;
    countText.value = "";
  }

  void _timeUp() {
    stopCount();
  }

  void dispose() {
    _countText?.dispose();
    _countText = null;
  }
}