在React Native中开发一个倒计时组件（CountDown）可以通过多种方式实现，例如使用原生的setTimeout方法、第三方库如react-native-countdown-circle或react-native-countdown-text等。下面我将详细介绍如何使用原生方法来实现一个简单的倒计时组件。

方法1：使用原生setTimeout

你可以通过使用JavaScript的setTimeout函数来创建一个简单的倒计时组件。以下是一个基本的实现方式：

1. 创建倒计时组件 (CountDownTimer.js)

import React, { useState, useEffect } from 'react';
import { View, Text, StyleSheet } from 'react-native';

const CountDownTimer = ({ initialTime, onComplete }) => {
    const [timeLeft, setTimeLeft] = useState(initialTime);

    useEffect(() => {
        let timer = setTimeout(() => {
            if (timeLeft > 0) {
                setTimeLeft(timeLeft - 1);
            } else {
                clearTimeout(timer);
                if (onComplete) {
                    onComplete();
                }
            }
        }, 1000);

        return () => clearTimeout(timer); // 清除定时器，防止内存泄漏
    }, [timeLeft]);

    return (
        <View style={styles.container}>
            <Text style={styles.text}>{timeLeft}</Text>
        </View>
    );
};

const styles = StyleSheet.create({
    container: {
        alignItems: 'center',
        justifyContent: 'center',
    },
    text: {
        fontSize: 24,
    }
});

export default CountDownTimer;

2. 在App中使用该组件

import React from 'react';
import { View } from 'react-native';
import CountDownTimer from './CountDownTimer'; // 确保路径正确

const App = () => {
    return (
        <View style={{ flex: 1, justifyContent: 'center', alignItems: 'center' }}>
            <CountDownTimer initialTime={10} onComplete={() => console.log('Time up!')} />
        </View>
    );
};

export default App;

方法2：使用第三方库（例如 react-native-countdown-text）

如果你希望更简便地实现，可以考虑使用第三方库。例如，react-native-countdown-text：

1. 安装库

npm install react-native-countdown-text --save

或者使用yarn：

yarn add react-native-countdown-text

2. 在App中使用该库

import React from 'react';
import { View } from 'react-native';
import CountdownText from 'react-native-countdown-text'; // 确保路径正确，可能需要调整为正确的导入路径或安装后自动生成的路径。

const App = () => {
    return (
        <View style={{ flex: 1, justifyContent: 'center', alignItems: 'center' }}>
            <CountdownText 
                startTime={10} // 初始时间，单位为秒，从10秒开始倒计时。 10 seconds to go. 1 second remaining. Time's up! 等等。 你可以自定义这些消息。 例如：messages={['还剩{seconds}秒', '{seconds}秒后开始']}。 具体细节请查阅库的文档。 默认值是：messages={['{seconds}秒后开始']}。 注意：这里的{seconds}是占位符，它将根据倒计时的剩余时间被替换。 若要自定义消息，可以这样设置：messages={['还剩{seconds}秒', '{seconds}秒后开始', '时间到！']}。 这样，当倒计时还剩5秒时，会显示“还剩5秒”；当倒计时开始时，会显示“5秒后开始”；当倒计时结束时，会显示“时间到！”。 若要完全自定义消息，可以省略占位符{seconds}，直接写上你想显示的消息。例如：messages={['即将开始', '开始', '完成']}。 这样，无论倒计时还剩多少秒，都会显示“即将开始”；当倒计时开始时，会显示“开始”；当倒计时结束时，会显示“完成”。 若要完全自定义消息，可以省略占位符{seconds}，直接写

---

真实场景案列演示：

// App.tsx
import React, { useState, useEffect } from 'react';
import { 
  View, 
  Text, 
  StyleSheet, 
  TouchableOpacity, 
  ScrollView, 
  SafeAreaView,
  Image,
  Dimensions,
  Alert
} from 'react-native';

// Base64 Icons for countdown components
const COUNTDOWN_ICONS = {
  timer: 'data:image/png;base64,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......',
  event: 'data:image/png;base64,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......',
  alarm: 'data:image/png;base64,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......',
  clock: 'data:image/png;base64,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......',
  deadline: 'data:image/png;base64,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......'
};

// 倒计时组件
interface CountdownTimerProps {
  initialTime: number; // seconds
  onComplete?: () => void;
  title: string;
  icon: string;
}

const CountdownTimer: React.FC<CountdownTimerProps> = ({
  initialTime,
  onComplete,
  title,
  icon
}) => {
  const [timeLeft, setTimeLeft] = useState(initialTime);
  const [isActive, setIsActive] = useState(false);
  const [isFinished, setIsFinished] = useState(false);

  useEffect(() => {
    let interval: NodeJS.Timeout | null = null;

    if (isActive && timeLeft > 0) {
      interval = setInterval(() => {
        setTimeLeft(prev => {
          if (prev <= 1) {
            setIsActive(false);
            setIsFinished(true);
            onComplete && onComplete();
            return 0;
          }
          return prev - 1;
        });
      }, 1000);
    } else if (!isActive && timeLeft !== 0) {
      clearInterval(interval!);
    }

    return () => {
      if (interval) clearInterval(interval);
    };
  }, [isActive, timeLeft, onComplete]);

  const startTimer = () => {
    setIsActive(true);
    setIsFinished(false);
  };

  const pauseTimer = () => {
    setIsActive(false);
  };

  const resetTimer = () => {
    setIsActive(false);
    setIsFinished(false);
    setTimeLeft(initialTime);
  };

  const formatTime = (seconds: number) => {
    const hrs = Math.floor(seconds / 3600);
    const mins = Math.floor((seconds % 3600) / 60);
    const secs = seconds % 60;
    
    return `${hrs.toString().padStart(2, '0')}:${mins.toString().padStart(2, '0')}:${secs.toString().padStart(2, '0')}`;
  };

  const getProgressPercentage = () => {
    return ((initialTime - timeLeft) / initialTime) * 100;
  };

  return (
    <View style={styles.timerContainer}>
      <View style={styles.timerHeader}>
        <Image source={{ uri: icon }} style={styles.timerIcon} />
        <Text style={styles.timerTitle}>{title}</Text>
      </View>
      
      <View style={styles.timerDisplayContainer}>
        <Text style={styles.timerDisplay}>{formatTime(timeLeft)}</Text>
        {isFinished && (
          <Text style={styles.finishedText}>时间到!</Text>
        )}
      </View>
      
      <View style={styles.progressBarContainer}>
        <View 
          style={[
            styles.progressBar,
            { width: `${getProgressPercentage()}%` }
          ]} 
        />
      </View>
      
      <View style={styles.timerControls}>
        {!isActive ? (
          <TouchableOpacity 
            style={[styles.controlButton, styles.startButton]} 
            onPress={startTimer}
          >
            <Text style={styles.buttonText}>开始</Text>
          </TouchableOpacity>
        ) : (
          <TouchableOpacity 
            style={[styles.controlButton, styles.pauseButton]} 
            onPress={pauseTimer}
          >
            <Text style={styles.buttonText}>暂停</Text>
          </TouchableOpacity>
        )}
        
        <TouchableOpacity 
          style={[styles.controlButton, styles.resetButton]} 
          onPress={resetTimer}
        >
          <Text style={styles.buttonText}>重置</Text>
        </TouchableOpacity>
      </View>
    </View>
  );
};

// 主应用组件
const App = () => {
  const handleTimerComplete = (timerName: string) => {
    Alert.alert(
      '倒计时完成',
      `${timerName} 已结束`,
      [{ text: '确定' }]
    );
  };

  return (
    <SafeAreaView style={styles.container}>
      <View style={styles.header}>
        <Text style={styles.headerTitle}>倒计时中心</Text>
        <Text style={styles.headerSubtitle}>多种场景倒计时工具</Text>
      </View>
      
      <ScrollView contentContainerStyle={styles.contentContainer}>
        <CountdownTimer
          initialTime={300} // 5 minutes
          onComplete={() => handleTimerComplete('会议倒计时')}
          title="会议倒计时"
          icon={COUNTDOWN_ICONS.timer}
        />
        
        <CountdownTimer
          initialTime={1800} // 30 minutes
          onComplete={() => handleTimerComplete('考试倒计时')}
          title="考试倒计时"
          icon={COUNTDOWN_ICONS.event}
        />
        
        <CountdownTimer
          initialTime={60} // 1 minute
          onComplete={() => handleTimerComplete('休息提醒')}
          title="休息提醒"
          icon={COUNTDOWN_ICONS.alarm}
        />
        
        <CountdownTimer
          initialTime={7200} // 2 hours
          onComplete={() => handleTimerComplete('任务截止')}
          title="任务截止倒计时"
          icon={COUNTDOWN_ICONS.deadline}
        />
        
        <View style={styles.infoSection}>
          <Text style={styles.infoTitle}>使用说明</Text>
          <Text style={styles.infoText}>
            • 点击"开始"启动倒计时{'\n'}
            • 点击"暂停"临时停止倒计时{'\n'}
            • 点击"重置"恢复初始时间{'\n'}
            • 倒计时结束后会有提示
          </Text>
        </View>
      </ScrollView>
      
      <View style={styles.footer}>
        <Text style={styles.footerText}>© 2023 倒计时工具. All rights reserved.</Text>
      </View>
    </SafeAreaView>
  );
};

const { width } = Dimensions.get('window');

const styles = StyleSheet.create({
  container: {
    flex: 1,
    backgroundColor: '#1a1a2e',
  },
  header: {
    backgroundColor: '#16213e',
    paddingTop: 20,
    paddingBottom: 25,
    paddingHorizontal: 20,
    borderBottomWidth: 1,
    borderBottomColor: '#0f3460',
  },
  headerTitle: {
    fontSize: 26,
    fontWeight: '700',
    color: '#e6e6ff',
    textAlign: 'center',
    marginBottom: 5,
  },
  headerSubtitle: {
    fontSize: 15,
    color: '#a9afc3',
    textAlign: 'center',
  },
  contentContainer: {
    padding: 20,
  },
  timerContainer: {
    backgroundColor: '#16213e',
    borderRadius: 16,
    padding: 20,
    marginBottom: 20,
    borderWidth: 1,
    borderColor: '#0f3460',
    shadowColor: '#000',
    shadowOffset: { width: 0, height: 4 },
    shadowOpacity: 0.3,
    shadowRadius: 6,
    elevation: 8,
  },
  timerHeader: {
    flexDirection: 'row',
    alignItems: 'center',
    marginBottom: 15,
  },
  timerIcon: {
    width: 32,
    height: 32,
    marginRight: 12,
    tintColor: '#4cc9f0',
  },
  timerTitle: {
    fontSize: 20,
    fontWeight: '700',
    color: '#e6e6ff',
  },
  timerDisplayContainer: {
    alignItems: 'center',
    marginVertical: 20,
  },
  timerDisplay: {
    fontSize: 36,
    fontWeight: '800',
    color: '#4cc9f0',
    fontFamily: 'monospace',
  },
  finishedText: {
    fontSize: 20,
    fontWeight: '700',
    color: '#f72585',
    marginTop: 10,
  },
  progressBarContainer: {
    height: 8,
    backgroundColor: '#0f3460',
    borderRadius: 4,
    overflow: 'hidden',
    marginVertical: 20,
  },
  progressBar: {
    height: '100%',
    backgroundColor: '#4cc9f0',
    borderRadius: 4,
  },
  timerControls: {
    flexDirection: 'row',
    justifyContent: 'space-between',
    marginTop: 15,
  },
  controlButton: {
    flex: 1,
    paddingVertical: 12,
    marginHorizontal: 5,
    borderRadius: 8,
    alignItems: 'center',
    justifyContent: 'center',
  },
  startButton: {
    backgroundColor: '#4cc9f0',
  },
  pauseButton: {
    backgroundColor: '#f72585',
  },
  resetButton: {
    backgroundColor: '#7209b7',
  },
  buttonText: {
    fontSize: 16,
    fontWeight: '700',
    color: '#ffffff',
  },
  infoSection: {
    backgroundColor: '#16213e',
    borderRadius: 16,
    padding: 20,
    marginTop: 10,
    borderWidth: 1,
    borderColor: '#0f3460',
  },
  infoTitle: {
    fontSize: 18,
    fontWeight: '700',
    color: '#e6e6ff',
    marginBottom: 10,
    textAlign: 'center',
  },
  infoText: {
    fontSize: 14,
    color: '#a9afc3',
    lineHeight: 22,
  },
  footer: {
    paddingVertical: 15,
    alignItems: 'center',
    borderTopWidth: 1,
    borderTopColor: '#0f3460',
    backgroundColor: '#16213e',
  },
  footerText: {
    fontSize: 14,
    color: '#a9afc3',
    fontWeight: '500',
  },
});

export default App;

这段React Native倒计时组件代码通过状态管理和副作用钩子实现了一个功能完整的计时器系统。组件内部维护三个核心状态：剩余时间、活动状态和完成状态，通过useEffect监听这些状态变化来启停计时器。当计时器处于活动状态时，每秒通过setInterval更新剩余时间，并在时间耗尽时触发完成回调。界面部分采用分层结构展示时间信息和操作按钮，通过条件渲染在不同状态下显示对应的控制元素。

在鸿蒙系统适配方面，这段代码面临着深刻的架构差异挑战。React Native的计时机制基于JavaScript的Event Loop和setInterval，这在鸿蒙的ArkUI框架中是完全不同的实现范式。鸿蒙采用基于TS的声明式UI开发，其时间处理依赖于系统级的时间服务而非浏览器环境下的计时API。

状态管理方面，React Native使用useState和useEffect的组合来管理组件生命周期，而鸿蒙通过@State和aboutToAppear等生命周期装饰器实现类似功能。这种差异导致在移植时需要重新设计组件的状态流转逻辑。

性能表现上，React Native的计时器由于运行在JavaScript线程，会受到桥接通信和JS执行效率的影响，特别是在多个计时器同时运行时会明显感知到性能瓶颈。鸿蒙的计时器直接与系统时间服务对接，能够提供更精确和稳定的计时体验。

事件处理机制也存在本质区别，React Native的触摸事件通过PanResponder系统处理，而鸿蒙使用Gesture组件直接绑定手势事件，这种底层差异使得交互逻辑需要完全重写。

布局系统的映射关系复杂，虽然都支持Flexbox布局，但在具体属性和默认行为上存在诸多细微差别，特别是在响应式设计和屏幕适配方面需要特别注意。

后台运行能力是另一个关键差异，React Native应用在后台时计时器可能被暂停，而鸿蒙提供了更完善的后台任务管理机制，能够保证计时器的连续性。

组件通信模式上，React Native通过props传递回调函数，而鸿蒙推荐使用@Link和@Prop装饰器实现父子组件间的数据同步，这种差异影响了组件的接口设计。

资源管理方面，React Native的图标资源通过URI引用，而鸿蒙使用ResourceManager统一管理应用资源，这导致资源加载机制需要调整。

---

打包

接下来通过打包命令npn run harmony将reactNative的代码打包成为bundle，这样可以进行在开源鸿蒙OpenHarmony中进行使用。

打包之后再将打包后的鸿蒙OpenHarmony文件拷贝到鸿蒙的DevEco-Studio工程目录去：

最后运行效果图如下显示：

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