我收到 "Invariant Violation" 错误的渲染方法有什么问题？

Question

我正在开始一个新的 React Native 项目，我使用了 'expo init' 并选择了一个空白的托管项目作为我的模板。我有几个来自不同项目的屏幕和组件，我想将它们复制到我的新项目中。我收到以下错误：

Invariant Violation: Element type is invalid: expected a string (for built-in components) or a class/function (for composite components) but got: undefined. You likely forgot to export your component from the file it's defined in, or you might have mixed up default and named imports.

Check the render method of CreateAccountForm.

我不知道发生了什么。我很确定我的所有设置都与我在第一个项目中所做的完全一样，这使一切都很好。我正在使用 React Navigation，我的新项目将 "HomeScreen" 呈现为 "initialRouteName"。但是，每当我尝试将初始路由设置为 'CreateNewAccountScreen' 时，我都会收到上述错误。

我已经测试过了，'CreateNewAccountScreen' 将渲染属性作为我的初始路由，只要它不尝试渲染嵌套在其中的 'CreateAccountForm' 组件。用简单的 <Text>Hi!<Text> 替换 <CreateAccountForm> 组件后，它可以毫无问题地渲染屏幕，以及 <Advertisement> 组件。

主屏幕：

import React from 'react';
import { StyleSheet, Image, Button, View } from 'react-native';
import Advertisement from '../components/Advertisement';

const HomeScreen = ({navigation}) => {
return (
    <View style={styles.mainContainer}>
      <View style={styles.logoContainer}>
        <Image style={styles.logo}
        source={require('../assets/TPLookupLogo.png')} 
        style={{height: 200, width: 350, marginBottom: 40}} 
        resizeMode="contain">
        </Image>
      </View>
      <View style={styles.btnsContainer}>
        <Button 
        style={styles.button}
        appearance="outline"
        onPress={()=>{console.log('To New User')}}
        title='New User'
        />
        <Button 
        style={styles.button} 
        appearance="outline"
        onPress={()=>{console.log('To Login')}}
        title='Login'
        />
      </View>
      <View style={styles.adContainer}>
        <Advertisement/>
      </View>
    </View>
    );
}

const styles = StyleSheet.create({
  mainContainer: {
    flex: 1,
    justifyContent: 'center', 
    alignItems: 'center',
  },
  logoContainer: {
    flex: 4,
    justifyContent: 'flex-end', 
    alignItems: 'center'
  },
  btnsContainer: {
    flex: 4,
    width: '40%',
    justifyContent: 'flex-start', 
  },
  button: {
    marginVertical: 4,
    },
  adContainer: {
    flex: 1,
    justifyContent: 'center',
    backgroundColor: 'black'
  }
})

export default HomeScreen;

AppNavigator:

import { createStackNavigator } from 'react-navigation-stack';
import HomeScreen from '../screens/HomeScreen';
import CreateNewAccountScreen from '../screens/CreateNewAccountScreen';

const AppNavigator = createStackNavigator(
    {
    Home: HomeScreen,
    CreateNewAccount: CreateNewAccountScreen

    },
    {
      initialRouteName: 'CreateNewAccount'
    }
  )

  export default AppNavigator;

CreateNewAccountScreen:

import React from 'react';
import { StyleSheet, View } from 'react-native'
import CreateAccountForm from '../components/CreateAccountForm';
import Advertisement from '../components/Advertisement';

const CreateNewAccountScreen = () => {
    return (
        <View style={styles.mainContainer}>
         <View style={styles.formContainer}>
           <CreateAccountForm/>
         </View>
         <View style={styles.adContainer}>
           <Advertisement/>
         </View> 
       </View>     
     );
}



const styles = StyleSheet.create({
    mainContainer:{
      flex: 1,
    },
    formContainer: {
      flex: 8,
    },
    adContainer: {
      flex: 1,
      justifyContent: 'center',
      backgroundColor: 'black'
    }
  })

CreateNewAccountScreen.navigationOptions = {
    headerTitle: 'Create Account'
}

export default CreateNewAccountScreen;

创建帐户表单：

import React, { useState } from 'react';
import { StyleSheet, View, Input, Button } from 'react-native';

const CreateAccountForm = () => {
    const [email, setEmail] = useState('');
    const [password, setPassword] = useState('');
    const [company, setCompany] = useState('');
    const [firstName, setFirstName] = useState('');
    const [lastName, setLastName] = useState('');
    const [address, setAddress] = useState('');
    const [city, setCity] = useState('');
    const [stateName, setStateName] = useState('');
    const [zip, setZip] = useState('');

    const onChangeEmailHandler = value => {
        setEmail(value);
    }

    const onChangePasswordHandler = value => {
        setPassword(value);
    }

    const onChangeCompanyHandler = value => {
        setCompany(value);
    }

    const onChangeFirstNameHandler = value => {
        setFirstName(value);
    }

    const onChangeLastNameHandler = value => {
        setLastName(value);
    }

    const onChangeAddressHandler = value => {
       setAddress(value);
    }

    const onChangeCityHandler = value => {
        setCity(value);
    }

    const onChangeStateNameHandler = value => {
        setStateName(value)
    }

    const onChangeZipHandler = value => {
        setZip(value);
    }

    const RegisterUserHandler = props => {
        let emailLength = email.length;
        let passwordLength = password.length;
        if (emailLength === 0 || passwordLength === 0)
        {
            console.log('Email & Password cannot be blank.');
        }
        else
        {
            registerUser()
        }
    }

    async function registerUser () {
        let headers = {
            'X-Authorization': "",
            'Accept': 'application/json',
            'Content-Type': 'application/json',
            };
        let body = JSON.stringify({
            Email: email,
            Password: password,
            Company: company,
            FirstName: firstName,
            LastName: lastName,
            Address: address,
            City: city,
            State: stateName,
            Zipcode: zip
        })
        let response = await fetch('', 
        {
            method: 'POST',
            headers: headers,
            body: body
        });
        let responseJson = await response.json()
    }

    return (
        <View style={styles.mainContainer}>
                <Input
                style={styles.input}
                type="text"
                value={email}
                placeholder="Email"
                onChangeText={onChangeEmailHandler}
                />
                <Input
                style={styles.input}
                type="text"
                value={password}
                placeholder="Password"
                onChangeText={onChangePasswordHandler}
                />
                <Input
                style={styles.input}
                type="text"
                value={company}
                placeholder="Company"
                onChangeText={onChangeCompanyHandler}
                />
                <Input
                style={styles.input}
                value={firstName}
                placeholder="First Name"
                onChangeText={onChangeFirstNameHandler}
                />
                <Input
                style={styles.input}
                value={lastName}
                placeholder="Last Name"
                onChangeText={onChangeLastNameHandler}
                />
                <Input
                style={styles.input}
                value={address}
                placeholder="Address"
                onChangeText={onChangeAddressHandler}
                />
                <View style={styles.rowInputsContainer}>
                    <Input 
                    style={styles.input}
                    value={city}
                    style={styles.rowInput}
                    placeholder="City"
                    onChangeText={onChangeCityHandler}
                    />
                    <Input
                    style={styles.input}
                    value={stateName}
                    style={{...styles.rowInput, ...styles.centerRowInput}}
                    placeholder="State"
                    onChangeText={onChangeStateNameHandler}
                    />
                    <Input
                    style={styles.input}
                    value={zip}
                    style={styles.rowInput}
                    placeholder="Zip"
                    onChangeText={onChangeZipHandler}
                    />
                </View>
                <Button 
                style={styles.btn}
                onPress={RegisterUserHandler}
                title='Register'
                />
        </View>
    )   
}

const styles = StyleSheet.create({
    mainContainer: {
      flex: 1,
      width: '75%',
      alignSelf: 'center',
      justifyContent: 'center',
    },
    rowInputsContainer: {
        display: 'flex',
        flexDirection: 'row',
        marginBottom: 16
    },
    rowInput: {
        flexGrow: 1,
    },
    centerRowInput: {
        marginHorizontal: 4
    },
    input: {
        marginVertical: 8
    }
})

export default CreateAccountForm;

在我的第一个应用程序中，这个完全相同的设置使一切都很好，没有问题。所以我不明白我哪里出错了。任何帮助，非常感谢，谢谢，和平！

Answer 1

React Native 有 TextInput 个组件而不是 Input 个组件。您可以在 CreateAccountForm.

中导入时检查一下吗

我收到 "Invariant Violation" 错误的渲染方法有什么问题？

What am I doing wrong with my render method that I'm receiving "Invariant Violation" error?

javascript

reactjs

react-native

react-native-navigation

expo