用react写一段动画循环播放的代码

Sure, here is an example of how to create a looped animation in React:

import React, { Component } from 'react';
import { Animated, View } from 'react-native';

class Animated extends Component {
  state = {
    fadeAnim: new Animated.Value(0),
  };

  componentDidMount() {
    Animated.loop(
      Animated.sequence([
        Animated.timing(this.state.fadeAnim, {
          toValue: 1,
          duration: 1000,
        }),
        Animated.timing(this.state.fadeAnim, {
          toValue: 0,
          duration: 1000,
        }),
      ]),
    ).start();
  }

  render() {
    const { fadeAnim } = this.state;

    return (
      <View style={{ flex: 1 }}>
        <Animated.View
          style={{
            opacity: fadeAnim,
            height: 100,
            width: 100,
            backgroundColor: 'red',
          }}
        />
      </View>
    );
  }
}

export default AnimatedLoop;

This code will create a simple animation that fades in and out repeatedly. The `componentDidMount()` lifecycle method is used to start the animation sequence, which is looped using the `Animated.loop()` method. The `Animated.timing()` method is used to animate the `fadeAnim` value. The `opacity` of the animated `View` is set to the `fadeAnim` value, causing it to fade in and out.