undefined 不是对象(评估 '_this3.props.navigation.navigate')

Question

屏幕之间的堆栈导航问题。我正在"SveKategorije"屏幕上显示数据。它基本上是类别按钮，当我单击按钮时，我现在只想显示另一个屏幕，但由于某种原因它不起作用。当我把 onPress={(( => this.props.navigation.navigate('screenname'(}它给了我这个错误我正在使用(反应原生 - 0.57.7(

这是路由器.js代码(我声明我的路由(

import React from 'react';
import { View, Text, Button } from "react-native";
import { createBottomTabNavigator, createStackNavigator } from "react-navigation";
import { Icon } from 'react-native-elements';
//TABS
import Categories from '../tabs/categories';
import Home from '../tabs/home';
import Me from '../tabs/me';
//screens for CATEGORIES 
import ViceviPoKategoriji from '../components/Ispis/ViceviPoKategoriji';
//CATEGORIES STACK 
export const categoriesFeedStack = createStackNavigator({
    SveKategorije: {
        screen: Categories,
        navigationOptions: {
            title: 'KATEGORIJE',
        },
    },
    ViceviPoKategoriji: {
        screen: ViceviPoKategoriji,
    }
});
//TABS
export const Tabs = createBottomTabNavigator({
    Categories: {
        screen: categoriesFeedStack,
        navigationOptions: {
            title: 'Kategorije',
            label: 'Kategorije',
            tabBarIcon: ({ tintColor }) => <Icon name="list" size={35} color={tintColor} />,
        }
    },
    Home: {
        screen: Home,
        navigationOptions: {
            title: 'Pocetna',
            label: 'Kategorije',
            tabBarIcon: ({ tintColor }) => <Icon name="home" size={35} color={tintColor} />,
        }
    },
    Me: {
        screen: Me,
        navigationOptions: {
            title: 'Profil',
            label: 'Kategorije',
            tabBarIcon: ({ tintColor }) => <Icon name="account-circle" size={35} color={tintColor} />,
        }
    },
},
    {
        initialRouteName: "Home",
        showIcon: true
    },
);

这是"SveKategorije"屏幕

import React from 'react';
import { StyleSheet, Text, View, ActivityIndicator, ScrollView, Button } from 'react-native';
import { createStackNavigator, createAppContainer, StackNavigator, navigate } from 'react-navigation';
export default class SveKategorije extends React.Component {
    constructor(props) {
        super(props);
        this.state = {
            isLoading: true,
            dataSource: null
        }
    }

    componentDidMount() {
        return fetch('http://centarsmijeha.com/api/allCategories')
            .then((response) => response.json())
            .then((responseJson) => {
                this.setState({
                    isLoading: false,
                    dataSource: responseJson.data,
                })
            })
            .catch((error) => {
                console.log(error)
            });
    }
    render() {
        if (this.state.isLoading) {
            return (
                <View style={styles.container}>
                    <ActivityIndicator />
                </View>
            )
        } else {
            let data = this.state.dataSource.map((val, key) => {
                return (
                    <View key={key} style={styles.item}>
                        <Button
                            onPress={() => this.props.navigation.navigate('ViceviPoKategoriji')}
                            title={val.categoryName}
                        />
                    </View>
                );
            });
            return (
                <ScrollView>
                    {data}
                </ScrollView >
            );
        }
    }
}

//CSS
const styles = StyleSheet.create({
    container: {
        flex: 1,
        backgroundColor: '#fff',
        alignItems: 'center',
        justifyContent: 'center',
        width: '100%'
    },
    item: {
        flex: 1,
        alignSelf: 'stretch',
        width: '100%',
        textAlign: 'center',
        alignItems: 'center',
        justifyContent: 'center'
    }
});

这是"ViceviPoKategoriji"屏幕(单击"SveKategorije"屏幕中的任何按钮时应显示的屏幕(

import React from 'react';
import { StyleSheet, Text, View, ActivityIndicator, ScrollView } from 'react-native';
export default class ViceviPoKategoriji extends React.Component {
    constructor(props) {
        super(props);
        this.state = {
            isLoading: true,
            dataSource: null,
        }
    }
    componentDidMount() {
        return fetch('http://centarsmijeha.com/api/jokesByCategory/16')
            .then((response) => response.json())
            .then((responseJson) => {
                this.setState({
                    isLoading: false,
                    dataSource: responseJson.data,
                })
            })
            .catch((error) => {
                console.log(error)
            });
    }
    render() {
        if (this.state.isLoading) {
            return (
                <View style={styles.container}>
                    <ActivityIndicator />
                </View>
            )
        } else {
            let data = this.state.dataSource.map((val, key) => {
                return <View key={key} style={styles.item}><Text>{val.jokeText}</Text></View>
            });
            return (
                <ScrollView>
                    {data}
                </ScrollView >
            );
        }
    }
}
const styles = StyleSheet.create({
    container: {
        flex: 1,
        backgroundColor: '#fff',
        alignItems: 'center',
        justifyContent: 'center',
    },
    item: {
        flex: 1,
        alignSelf: 'stretch',
        marginTop: 50,
        marginRight: '15%',
        marginLeft: '15%',
        width: '70%',
        textAlign: 'center',
        alignItems: 'center',
        justifyContent: 'center',
        borderBottomWidth: 1,
        borderBottomColor: '#eee'
    }
});

Answer 1

React-navigation是基于道具的导航。我认为您的组件没有导航道具。请检查您的组件是否有导航道具。

做

render() {
  console.log(this.props.navigation)
  // or debugger
  return (

如果未定义控制台的结果.log，则将"导入 SveKategorije"添加到路由文件中。

Answer 2

您必须再进行一些设置才能从组件导航。您可以通过 ref 访问导航器，并将其传递给导航服务，我们稍后将用于导航。

https://reactnavigation.org/docs/en/navigating-without-navigation-prop.html

Answer 3

就我而言，我不小心在功能组件中使用了this.props.navigation。如果有人犯了这样的错误，将再次检查您的代码。