Javascript 在React Native上接收消息MQTT时更新值?
我对使用React还相当陌生,我正在做一个项目来学习 当我在mqtt中收到带有this.setState的消息时,我试图更新一个值,但它抛出了一个错误(this.setState不是函数)Javascript 在React Native上接收消息MQTT时更新值?,javascript,reactjs,mqtt,Javascript,Reactjs,Mqtt,我对使用React还相当陌生,我正在做一个项目来学习 当我在mqtt中收到带有this.setState的消息时,我试图更新一个值,但它抛出了一个错误(this.setState不是函数) import'/App.css'; 从“./components/Chart”导入圆环图; var mqtt=require('mqtt') var host='ws://localhost:9003' var client=mqtt.connect(主机) 类应用程序扩展组件{ 构造函数(){ 超级();
import'/App.css';
从“./components/Chart”导入圆环图;
var mqtt=require('mqtt')
var host='ws://localhost:9003'
var client=mqtt.connect(主机)
类应用程序扩展组件{
构造函数(){
超级();
此.state={
答复:[5,7],
答复2:[5,7],
}
}
componentDidMount(){
client.on('connect',function(){
console.log('客户端已连接:')
subscribe('topic',{qos:0})
})
client.on('message',函数(主题、消息、数据包){
console.log('收到的消息:='+消息.toString()+'\n主题:='+主题)
this.setState({response2:[4,96]});
})
}
render(){
返回(
);
}
}
导出默认应用程序;
kkk
import './App.css';
import DoughnutChart from './components/Chart';
var mqtt = require('mqtt')
var host = 'ws://localhost:9003'
var client = mqtt.connect(host)
class App extends Component {
constructor(){
super();
this.state = {
response: [5,7],
response2: [5,7],
}
}
componentDidMount() {
client.on('connect', function () {
console.log('client connected:')
client.subscribe('topic', { qos: 0 })
})
client.on('message', function (topic, message, packet) {
console.log('Received Message:= ' + message.toString() + '\nOn topic:= ' + topic)
this.setState({ response2: [4,96]});
})
}
render() {
return (
<div className="App">
<DoughnutChart id="Tercer" temp={this.state.response}/>
<DoughnutChart id="cuarto" temp={this.state.response2}/>
</div>
);
}
}
export default App;