Question

错误出现在我定义onIncrease和onDecrease的行中。在React-native上一堂课之后，我编写了与上课相同的代码，但出现此错误。有人可以帮忙吗？。

import React, {useState} from 'react';
import {View, Text, StyleSheet} from 'react-native';
import ColorCounter from '../components/ColorCounter';

const COLOR_INCREMENT = 15;

const SquareScreen = () => {
  const [red, setRed] = useState(0);
  const [green, setGreen] = useState(0);
  const [blue, setBlue] = useState(0);

  const setColor = (color, change) => {
    switch (color) {
      case 'red':
        red + change > 255 ||  red + change < 0 ? null: setRed(red + change);
        return;
      case 'green':
        green + change > 255 ||  green + change < 0 ? null: setGreen(green + change);
        return;
      case 'blue':
        blue + change > 255 ||  blue + change < 0 ? null: setBlue(blue + change);
        return;
      default:
        return;
    }
  };

  return (
    <View>
      <ColorCounter onIncrease{() => setColor('red', COLOR_INCREMENT)} onDecrease{() => setColor('red', -1 * COLOR_INCREMENT)} color="Red"/>
      <ColorCounter
        onIncrease{() => setColor('blue', COLOR_INCREMENT)}
        onDecrease{() => setColor('blue', -1 * COLOR_INCREMENT)}
        color="Blue"
      />
      <ColorCounter
        onIncrease{() => setColor('green', COLOR_INCREMENT)}
        onDecrease{() => setColor('green', -1 * COLOR_INCREMENT)}
        color="Green"/>
    </View>
  );
};

const styles = StyleSheet.create({});

export default SquareScreen;

Answer 1

也许您缺少情感标记=？

onIncrease = {() => setColor('blue', COLOR_INCREMENT)}
onDecrease = {() => setColor('blue', -1 * COLOR_INCREMENT)}

React native给出了“意外的令牌，预期为'...'”，但不明白为什么？

1 个答案: