如何从onMessageArrive检索payloadString到构造函数

Question

请检查代码。我想从onMessageArrive检索payloadString数据到构造函数。怎么做？基本上，我想将所有 JSON 数据存储在 Asyncstorage 中，并且还想在构造函数中应用一些逻辑。这就是为什么我想从onMessageArrive检索数据到构造函数。提前谢谢。

import React, { Component } from 'react';
import init from 'react_native_mqtt';
import { AsyncStorage, StyleSheet, Text, View } from 'react-native';
init({
  size: 10000,
  storageBackend: AsyncStorage,
  defaultExpires: 1000 * 3600 * 24,
  enableCache: true,
  sync: {},
});

export default class MqttLog extends Component {
  constructor(props) {
    super(props);
    const client = new Paho.MQTT.Client('iot.eclipse.org', 443, 'uname');
    client.onConnectionLost = this.onConnectionLost;
    client.onMessageArrived = this.onMessageArrived;
    client.connect({ onSuccess: this.onConnect, useSSL: true });

    this.state = {
      text: ['ELOGIC'],
      client,
    };
    this.onMessageArrived.bind(this);
  }

  onConnect = () => {
    const { client } = this.state;
    client.subscribe('WORLD');
    console.log('connect');
  };
  onConnectionLost = responseObject => {
    if (responseObject.errorCode !== 0) {
      var connectionLostMessage = `connection lost: ${responseObject.errorMessage}`;
      console.log(connectionLostMessage);
    }
  };
  onMessageArrived = message => {
    var msg = message.payloadString;
    var messageResult = `${msg}`;
    console.log(messageResult);
  };
  render() {

    return (
      <View style={styles.container}>
        <Text>Hello</Text>
      </View>
    );
  }
}

const styles = StyleSheet.create({
  container: {
    width: '100%',
    height: '100%',
  },
});

Answer 1

能够通过使用异步存储来解决此问题。当数据来自 mqtt 时，我会立即在异步存储中推送数据，然后使用构造函数中的键值对从异步存储中检索。