无法让状态在 React Native 中工作

Question

我对 React Native 中的状态概念还很陌生，无法使用它们来更改组件的状态。我有三个文本组件，一个是问题，另外两个是答案（是和否），另一个文本组件检查我对问题的回答是否已写，因此检查文本组件。当我针对某个问题单击“是”时，如果答案为“是”，则最后一个检查组件的状态应更改为“正确”，如果答案为“否”，则更改为“错误”。所以基本上，这就是我想要做的：

这是我到目前为止所拥有的：

这是我得到的错误：

这是我到目前为止的代码：

import React, { useState, useEffect } from 'react';

import { StyleSheet, Text, View, TouchableOpacity, Alert, ScrollView, Image } from 'react-native';

// import TextComp from './components/Home2'

export default function App() {

  const [answer, setAnswer] = useState('answer');

  const [correctAns, setCorrectAns] = useState('');

  const useEffect = () => {

    if (answer == 'answer') {

      setCorrectAns('please answer!');

    } else if (answer == 'Yes') {

      setCorrectAns('Right');

    } else if (answer == 'No') {

      setCorrectAns('Wrong');

    };

  };

  const corAns = () => { Alert('Your answer was ', correctAns) }

  return (

    <ScrollView style={styles.container}>

      <View style={{ alignItems: 'center' }}>

        <Image source={require('./images/pic.jpeg')} style={styles.uriImg} />

        <Text style={styles.title}>Is this Mt. Fuji?</Text>

        <TouchableOpacity

          onPress={() => setAnswer('Yes')}>

          <Text style={styles.text}>Yes</Text>

        </TouchableOpacity>

        <TouchableOpacity

          onPress={() => setAnswer('No')}>

          <Text style={styles.text}>No</Text>

        </TouchableOpacity>

        <TouchableOpacity

          onPress={corAns}>

          <Text style={styles.text2}>Check</Text>

        </TouchableOpacity>

        <Image source={require('./images/yellow.png')} style={styles.uriImg} />

}

谁能告诉我怎么做？谢谢！

Answer 1

像这样使用 useEffectuseEffect(() => {&nbsp;if (answer === 'Yes') {&nbsp; Alert.alert('Right')&nbsp;}&nbsp;if (answer === 'No') {&nbsp;Alert.alert('Wrong')&nbsp;}}, [ answer ])或按检查按钮&nbsp; &nbsp;const checkAnswer = () => {&nbsp; &nbsp; &nbsp;if (answer === 'Yes') {&nbsp; &nbsp; &nbsp; Alert.alert('Right')&nbsp; &nbsp; &nbsp;}&nbsp; &nbsp; &nbsp;if (answer === 'No') {&nbsp; &nbsp; &nbsp;Alert.alert('Wrong')&nbsp; &nbsp; &nbsp;}&nbsp; &nbsp; &nbsp;if (answer === 'answer') {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; Alert.alert('please answer')&nbsp; &nbsp; &nbsp;}&nbsp; &nbsp; }设置检查按钮 onPress={checkAnswer}