javascript 希望使用redux而不是useState来更新stae

vjhs03f7  于 2023-02-21  发布在  Java
关注(0)|答案(1)|浏览(96)

我目前正在尝试学习Redux,但我在使用Redux管理状态时遇到了麻烦。现在我可以使用useState来管理状态,它可以工作,但使用Redux无法计算出它。现在我的应用程序只是试图在输入字段中输入文本,当按下按钮时,它会将其添加到平面列表状态。

import { connect } from 'react-redux';
import {View,Text,Button,TextInput,FlatList,ScrollView,} from 'react-native';
import { useState } from 'react';
import { Add_Item } from '../redux/actions/index';

const mapStateToProps = (state) => {
  return { tasks: state.reducer.tasks };
};
const mapDispatchToProps = { Add_Item };
function App({ tasks, Add_Item }) {
const [add, setAdd] = useState('');
return (
<ScrollView>
  <View style={{paddingTop: 20}}>
    <View style={{ border: '2px solid green', margin: 10 }}>
      <TextInput
        placeholder="Enter Value Here"
        onChangeText={(add) => setAdd(add)}
      />
    </View>
    <View
      style={{
        padding: 3,
        border: '2px solid green',
        backgroundColor: 'green',
        'border-radius': 15,
        margin: 10,
      }}>
      <Button
        title="Add Values to Flatlist"
        onPress={() => Add_Item(add)}
        color="green"
      />
    </View>

    <FlatList
      data={tasks}
      renderItem={({ item }) => (
        <View>
          <Text
            style={{
              borderBottomColor: 'grey',
              borderBottomWidth: 1,
              padding: 5,
            }}>
            {item.title}
          </Text>
        </View>
      )}
    />
  </View>
</ScrollView>
);
}

export default connect(mapStateToProps, mapDispatchToProps)(App);

我的文本转换器文件:

import { ADD_ITEM } from '../actionType/index';

var initialState = {
tasks: [],
};
export default function (state = initialState, action) {
 if (action.type == ADD_ITEM) {
  return {...state, 
  tasks: [...state.tasks,{title:action.payload.title}]}
 }

 return state;
}

我的存储文件:

import { configureStore } from "@reduxjs/toolkit";
import reducer from "../reducers/index";
export default configureStore({reducer});

我的app. js:

import React, { useState } from 'react';
import { View } from 'react-native';
import {Provider} from 'react-redux';
import store from './redux/store/index';
import AddApp from './FlatListApp/index'
export default function App() {
  return (
   <Provider store={store}>
    <AddApp/>
   </Provider>
  );
}
lymnna71

lymnna711#

问题是您正在mapDispatchToProps和App中使用Add_Item本身,您必须在mapDispatchToProps中重命名Add_Item,然后在App中使用它:

import { connect } from 'react-redux';
import {View,Text,Button,TextInput,FlatList,ScrollView,} from 'react-native';
import { useState } from 'react';
import { Add_Item } from '../redux/actions/index';

const mapStateToProps = (state) => {
  return { tasks: state.reducer.tasks };
};
const mapDispatchToProps = {addItemAction: Add_Item };
function App({ tasks, addItemAction }) {
const [add, setAdd] = useState('');
return (
<ScrollView>
  <View style={{paddingTop: 20}}>
    <View style={{ border: '2px solid green', margin: 10 }}>
      <TextInput
        placeholder="Enter Value Here"
        onChangeText={(add) => setAdd(add)}
      />
    </View>
    <View
      style={{
        padding: 3,
        border: '2px solid green',
        backgroundColor: 'green',
        'border-radius': 15,
        margin: 10,
      }}>
      <Button
        title="Add Values to Flatlist"
        onPress={() => addItemAction(add)}
        color="green"
      />
    </View>

    <FlatList
      data={tasks}
      renderItem={({ item }) => (
        <View>
          <Text
            style={{
              borderBottomColor: 'grey',
              borderBottomWidth: 1,
              padding: 5,
            }}>
            {item.title}
          </Text>
        </View>
      )}
    />
  </View>
</ScrollView>
);
}

export default connect(mapStateToProps, mapDispatchToProps)(App);

但是我建议您使用钩子而不是connect,redux团队也建议您使用redux工具包。

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