React Native Redux：错误找不到变量mapStateToProps

Question

我一直在尝试将 Redux 实施到我正在创建的多页表单设置的 React-Native 注册应用程序中。

我不断收到此错误：

请查看应用程序根容器下方的相关代码：

import React, { Component } from 'react';
import ReactNative from 'react-native';
import { AppRegistry,Text,View,} from 'react-native';
import { Button } from 'react-native-elements'
import { StackNavigator } from 'react-navigation'
import store from '../store/store';
import { Provider,connect } from  'react-redux';
import Register1 from './emailandpass'
import Register2   from './namefields'
//import login      from './login'
//import confirmation from './confirmation'
//import success      from './success'

class Loginscreen extends React.Component{
	static navigationOptions= {
		title: 'Welcome to LearnD',
							 }
  render() {
  	const { navigate  } = this.props.navigation;
    return(
      <Provider store={store}> 
      <View>
      <Text>Have you got an account ?</Text>
      <Button
        onPress={()=> navigate('Register1')}
        title="Register here !"
        />
      </View>
      </Provider> 

    );
  }
};

const App = StackNavigator({
 	Home: { screen: Loginscreen},
 	Register1: {screen: Register1  },
 	Register2: {screen: Register2}
});

export default connect(mapStateToProps)(Landingscreen);

任何帮助，将不胜感激

Answer 1

这个错误是不言自明的。

您试图将一个名为的变量传递mapStateToProps到connect函数中，但您从未定义它。

export default connect(mapStateToProps)(Landingscreen);
//                     ^ this isn't defined anywhere

您实际上需要创建一个将状态映射到 props 的函数：

function mapStateToProps(state) {
  // ...
}
export default connect(mapStateToProps)(Landingscreen);