堆栈导航器给我未定义的错误

Question

顺便说一句，我正在使用https://facebook.github.io/react-native/docs/navigation.html。

我正在尝试使用StackNavigator 从Login.js 转到AboutDendro.js。我的<Button/> 组件有什么问题在我的iOS 模拟器中抛出该错误？

这里是Login.js：

import React, { Component } from 'react';
import { connect } from 'react-redux';
import { ScrollView, Text, TextInput, View, Button, StyleSheet } from 'react-native';
import { login } from '../redux/actions/auth';
import {AuthenticationDetails, CognitoUser, CognitoUserAttribute, CognitoUserPool} from '../lib/aws-cognito-identity';
import StackNavigator from 'react-navigation';
import AboutDendro from './AboutDendro';

const awsCognitoSettings = {
    UserPoolId: 'something',
    ClientId: 'something'
};

class Login extends Component {
    constructor (props) {
        super(props);
        this.state = {
            page: 'Login',
            username: '',
            password: ''
        };
    }

    get alt () { return (this.state.page === 'Login') ? 'SignUp' : 'Login'; }

    handleClick (e) {
        e.preventDefault();
        const userPool = new CognitoUserPool(awsCognitoSettings);

        // Sign up
        if (this.state.page === 'SignUp') {
            const attributeList = [
                new CognitoUserAttribute({ Name: 'email', Value: this.state.username })
            ];
            userPool.signUp(
                this.state.username,
                this.state.password,
                attributeList,
                null,
                (err, result) => {
                    if (err) {
                        alert(err);
                        this.setState({ username: '', password: '' });
                        return;
                    }
                    console.log(`result = ${JSON.stringify(result)}`);
                    this.props.onLogin(this.state.username, this.state.password);
                }
            );
        } else {
            const authDetails = new AuthenticationDetails({
                Username: this.state.username,
                Password: this.state.password
            });
            const cognitoUser = new CognitoUser({
                Username: this.state.username,
                Pool: userPool
            });
            cognitoUser.authenticateUser(authDetails, {
                onSuccess: (result) => {
                    console.log(`access token = ${result.getAccessToken().getJwtToken()}`);
                    this.props.onLogin(this.state.username, this.state.password);
                },
                onFailure: (err) => {
                    alert(err);
                    this.setState({ username: '', password: '' });
                    return;
                }
            });
        }
    }

    togglePage (e) {
        this.setState({ page: this.alt });
        e.preventDefault();
    }

    static navigationOptions = {
        title: 'AboutDendro',
    };

    render() {
        const { navigate } = this.props.navigation;
        const App = StackNavigator({
            Home: { screen: Login },
            Profile: { screen: AboutDendro },
        });

        return (
            <ScrollView style={{padding: 20}}>
                <Button
                    title="Go to Jane's profile"
                    onPress={() =>
                        navigate('AboutDendro', { name: 'AboutDendro' })
                    }
                />
                <Text style={{fontSize: 27}}>{this.state.page}</Text>
                <TextInput
                    placeholder='Email Address'
                    autoCapitalize='none'
                    autoCorrect={false}
                    autoFocus={true}
                    keyboardType='email-address'
                    value={this.state.username}
                    onChangeText={(text) => this.setState({ username: text })} />
                <TextInput
                    placeholder='Password'
                    autoCapitalize='none'
                    autoCorrect={false}
                    secureTextEntry={true}
                    value={this.state.password}
                    onChangeText={(text) => this.setState({ password: text })} />
                <View style={{margin: 7}}/>
                <Button onPress={(e) => this.handleClick(e)} title={this.state.page}/>
                <View style={styles.firstView}>
                    <Text onPress={(e) => this.togglePage(e)} style={styles.buttons}>
                        {this.alt}
                    </Text>
                </View>
            </ScrollView>
        );
    }
}

const styles = StyleSheet.create({
    buttons: {
        fontSize: 12,
        color: 'blue',
        flex: 1
    },

    firstView: {
        margin: 7,
        flexDirection: 'row',
        justifyContent: 'center'
    }
});

const mapStateToProps = (state, ownProps) => {
    return {
        isLoggedIn: state.auth.isLoggedIn
    };
}

const mapDispatchToProps = (dispatch) => {
    return {
        onLogin: (username, password) => { dispatch(login(username, password)); }
    }
}

export default connect(mapStateToProps, mapDispatchToProps)(Login);

Answer 1

这是因为navigation 不在您的道具中。它是您创建的App 组件的一部分。但是你对这个组件什么都不做。

您应该有一个App.js 文件，在您的 stackNavigator 中，将您的 Login 组件设置为您的 stackNavigator 参数中的默认组件。

看看this documentation

Answer 2

我尝试重构您的代码。 在组件render 也许你可以写：

render() {
    const { navigate } = this.props.navigation;
    return (
        <ScrollView style={{padding: 20}}>
            <Button
                title="Go to Jane's profile"
                onPress={() =>
                    navigate('Profile', { name: 'AboutDendro' })
                }
            />
            <Text style={{fontSize: 27}}>{this.state.page}</Text>
            <TextInput
                placeholder='Email Address'
                autoCapitalize='none'
                autoCorrect={false}
                autoFocus={true}
                keyboardType='email-address'
                value={this.state.username}
                onChangeText={(text) => this.setState({ username: text })} />
            <TextInput
                placeholder='Password'
                autoCapitalize='none'
                autoCorrect={false}
                secureTextEntry={true}
                value={this.state.password}
                onChangeText={(text) => this.setState({ password: text })} />
            <View style={{margin: 7}}/>
            <Button onPress={(e) => this.handleClick(e)} title={this.state.page}/>
            <View style={styles.firstView}>
                <Text onPress={(e) => this.togglePage(e)} style={styles.buttons}>
                    {this.alt}
                </Text>
            </View>
        </ScrollView>
    );
  }
}

然后你将组件 StackNavigation 分隔在组件 render() 下方，例如：

 const App = StackNavigator({
        Home: { screen: Login },
        Profile: { screen: AboutDendro },
    });

然后在您的index.ios.js 中导入组件应用程序，例如：

import './Login';

就是这样。或许我的回答对你有帮助。