未定义的不是计算route.params.input的对象.在组件之间传递数据时出错.反应自然

Question

在将文本输入从一个屏幕传递到另一个屏幕时，我收到了上述错误。有趣的是，当应用程序启动时会出现错误，导致应用程序崩溃。但是，如果我删除下面代码中的行：const｛input｝=route.params；运行应用程序。它不会崩溃。因此，我可以通过文本输入导航到屏幕。放入一些文本。然后加回const｛input｝=route.params；该应用程序正常工作，数据在屏幕之间传递。如果我刷新应用程序，它就会崩溃。我试着对一些数据进行硬编码，这样当应用程序启动时，Textinput就不会为空。它不起作用，应用程序在发布时仍然崩溃。下面是我的代码？你知道为什么会发生上述行为吗？

在这里，我在屏幕上导航：文本输入所在的Opci Podaci，还显示数据｛input｝：

import React, {useContext, useState} from "react";
import styled from "styled-components";
import { Text, View, ScrollView} from "react-native";
import {List} from "react-native-paper";
import { OpciPodaciOglasInput } from "../../components/iznajmljivanje.PodaciInput/opciPodaciInput";
export const IznajmiScreen = ({navigation, route}) => {
const { input } = route.params;

return (
<>
<SectionContainer>
<ScrollView>
<List.Accordion
title="Detalji Oglasa"
left={(props) => <List.Icon {...props} icon="car-sports" />}
expanded={detaljiExpanded}
onPress={() => setDetaljiExpanded(!detaljiExpanded)}
>
<List.Item  title="Unesi Opis..."
onPress={()=>navigation.navigate("Opci Podaci")} />
<List.Item />
</List.Accordion>

<Text>{input}</Text>

</ScrollView>
</SectionContainer>
</>
);
};

文本输入屏幕(代码中的Opci podaci(：

import React, {useState} from "react";
import styled from "styled-components";
import {TextInput, View, StyleSheet, Text, Button} from "react-native";
export const OpciPodaciOglasInput = ({navigation}) => {
const [input, setInput] = useState("");
return( 
<>
<Button title="Save"
onPress={()=>navigation.navigate("Rent a car", {input})}/>
<InputContainer>
<Text>Unesi Podatke</Text>
<TextInput style={styles.input} 
placeholder="300 rijeci maximum"
multiline = {true}
maxLength={300}
onChangeText={(text)=> setInput(text)}
returnKeyType='done'
value={input}
onSubmitEditing={()=>{
navigation.navigate('Rent a car',{input});
setInput("");
}}
/>
</InputContainer>  
</>
);
};

我的导航：

import React from "react";
import { Button } from "react-native";
import {createStackNavigator, CardStyleInterpolators} from "@react-navigation/stack";
import { IznajmiScreen } from "../screens/tabNavigation.screens/iznajmiScreen";
import { OpciPodaciOglasInput } from "../components/iznajmljivanje.PodaciInput/opciPodaciInput";
const IznajmiStack = createStackNavigator();
export const IznajmiScreenNavigator = ({ route, navigation }) => {
return (
<IznajmiStack.Navigator
screenOptions="screen"
screenOptions={{
cardStyleInterpolator: CardStyleInterpolators.forHorizontalIOS,
}}
>
<IznajmiStack.Screen
options={{headerRight:()=>(<Button title="Predaj Oglas"
onPress={()=>{}}/>)}} //TODO on PRESS
name="Rent a car"
component={IznajmiScreen}
/>
<IznajmiStack.Screen name="Opci Podaci" component={OpciPodaciOglasInput}/>
</IznajmiStack.Navigator>
);
};

Answer 1

问题是行const { input } = route.params;-在react导航填充route对象之前，您将在尝试引用其嵌套属性时出错。安全访问route对象将防止这种情况，即

const { input } = route?.params || {};