找不到变量:调度

你好,世界

我正在运行我的react-native应用程序,但遇到诸如以下错误:找不到变量:dispatch我正在使用reducer在此应用程序中管理不同状态!任何帮助将不胜感激!

import React, {useReducer} from 'react';
import {Button, Text, View} from 'react-native';

const reducer = (state, action) => {

    switch (action.colorToChange) {
        case 'red':
            return {...state, red: state.red + action.amount};
        case 'green':
            return {...state, green: state.green + action.amount};
        case 'blue':
            return {...state, blue: state.blue + action.amount};
        default:
            return state;
    }
};

const HomeScreen = () => {
    const [state, action] = useReducer(reducer, {red: 0, green: 0, blue: 0});
    const {red, green, blue} = state;

    return (
        <View>
            <Button title="Red"  onPress=() => {dispatch({colorToChange: 'red', amount: 1})}/>
            <Button title="Green" onPress={() => dispatch({colorToChange: 'green', amount: 1})}/>
            <Button title="Blue"  onPress={() => dispatch({colorToChange: 'blue', amount: 1})}/>

            <Text>Red Color:{red}</Text>
            <Text>Green Color:{green}</Text>
            <Text>Blue Color:{blue}</Text>
        </View>
    );
};

export default HomeScreen;
斯迈尔·加利贾瑟维奇

如果您将useReducer命名为action,则将其作为分派后的数组的第二个元素返回调度,您应该将use reducer行更改为

 const [state, dispatch] = useReducer(reducer, {red: 0, green: 0, blue: 0});

之后,您将可以使用dispatch ..您现在可以通过调用action()来使用它。但是命名似乎很错误

本文收集自互联网,转载请注明来源。

如有侵权,请联系[email protected] 删除。

编辑于
0

我来说两句

0条评论
登录后参与评论

相关文章