React-Native：將組件導入App.js時出錯

Question

使用expo從組件導入默認類時出現錯誤，我搜索此錯誤，但未解決問題，組件返回object。

type is invalid -- expected a string (for built-in components) or a class/function (for composite components) 但得到了：對象

錯誤：

12:19:03: Warning: React.createElement: type is invalid -- expected a string (for built-in components) or a class/function (for composite components) but got: object. 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 your code at registerRootComponent.js:35.
    in ExpoRootComponent (at renderApplication.js:33)
    in RCTView (at View.js:60)
    in View (at AppContainer.js:102)
    in RCTView (at View.js:60)
    in View (at AppContainer.js:122)
    in AppContainer (at renderApplication.js:32)

App.js

import Login from './app/components/login';

應用/組件/登錄/ index.js

import React, {Component} from 'react';
import {Text, View} from 'react-native';

export default class Login extends Component {
    constructor(props){
        super(props);
        this.state = {}
    }
    render(){
        return(
            <View>
             <Text>Login</Text>
            </View>
        )
    }
}

Answer 1

在App.js對Login組件使用默認導入。 另外，從App.js導出根組件

import React from "react";
import Login from './app/components/login';

export default class App extends React.Component {
  render() {
    return <Login/>;
  }
}