javascript - 元素类型无效 : expected a string/class/function got: object

Question

我正在开发 React-Native 项目，在尝试实现 React-navigation 时遇到了问题。我按照教程进行操作，当尝试运行该项目时，出现错误:

Element 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.

我搜索了网络，包括这个网站，但找不到任何解决方案。这是我的代码:索引.js:

import React, { Component } from 'react';
import { Stack } from './config/Router';

class Application extends Component{
  render(){
    <View>
      return <Stack />;
    </View>
  }
}

export default Application;

这是路由器:

import React from 'react';
import { StackNavigator } from 'react-navigation';

import Login from '../components/Login';
import Home from '../components/Home';

export const Stack = StackNavigator({
  Login:{
    screen: Login
  },
  Home:{
    screen: Home,
    navigationOptions: {
      title: 'Home'
    }
  }
});

这是index.ios.js:

import { AppRegistry } from 'react-native';
import Application from './index'

AppRegistry.registerComponent('Application', () => Application);

如何修复该错误？提前致谢!

Answer 1

看起来像

class Application extends Component{
  render(){
    <View>
      return <Stack />;
    </View>
  }
}

应该是

class Application extends Component{
  render(){
    return(
      <View>
        <Stack />
      </View>
    );
  }
}

您还需要在index.js中导入View组件

您可能忘记从定义它的文件中导出组件。

这几乎总是您收到无效元素错误的原因，因此请务必仔细检查您的导入。