javascript - 运行样板 react 导航应用程序时的 "undefined is not an object (evaluating ' Component.router ')"

Question

我是 react 原生的新手，想尝试 react 导航。但是，当我尝试运行基本应用程序时，它给出了“未定义不是对象(评估“Component.router”)”错误。请帮忙

这是错误的屏幕截图 https://i.gyazo.com/fa89defeff8bef894f509f1511f9b1ae.png

除了安装之外，这是我在默认项目中唯一更改的内容 react 导航和 react native 手势处理程序

import React, {Component} from 'react';
import {Platform, StyleSheet, Text, View} from 'react-native';
import {createAppContainer,
        createSwitchNavigator,
        createStackNavigator} from 'react-navigation';

type Props = {};
export default class App extends Component<Props> {
  render() {
    return <AppNavigator/>;
  }
}

class MainScreen extends Component{
  render(){
    return <Text>Hi</Text>
  }
}

const AppNavigator = createAppContainer(SwitchNavigator);

const SwitchNavigator = createSwitchNavigator({
  MainScreen : MainScreen,

});```

Answer 1

您的代码中有两个问题

(1) 您正尝试在声明之前访问 SwitchNavigator。(2) 您正在执行MainScreen : MainScreen，这会导致错误。

const SwitchNavigator = createSwitchNavigator({
  MainScreen,
});

或

// optionally pass an object to your route, with screen, navigation options
const SwitchNavigator = createSwitchNavigator({
  MainScreen: { screen: MainScreen },
});

const AppNavigator = createAppContainer(SwitchNavigator);