推荐一款炫酷的React/React Native倒计时组件：Countdown Circle Timer

import React from 'react';
import { Text, View } from 'react-native';
import CountdownCircleTimer from "react-native-countdown-circle-timer";
 
const App = () => (
  <View style={{ flex: 1, justifyContent: "center", alignItems: "center" }}>
    <CountdownCircleTimer
      seconds={10}
      radius={30}
      borderWidth={8}
      color={"#FF6347"}
      onTimeElapsed={() => console.log("倒计时结束！")}
    >
      {({ remainingTime, elapsedTime }) => (
        <Text style={{ fontSize: 40 }}>
          {remainingTime}
        </Text>
      )}
    </CountdownCircleTimer>
  </View>
);
 
export default App;

这段代码展示了如何在React Native应用程序中使用CountdownCircleTimer组件来创建一个10秒的倒计时器。组件通过一系列样式定制选项提供了多种定制功能，并允许开发者通过children属性自定义显示格式。当倒计时结束时，会在控制台输出"倒计时结束！"的信息。