android - 使用 BLE Android 连接到设备

Question

我正在尝试在 Android 设备上使用 React-Native 中的 BLE 连接来连接到设备。我需要连接到具有特定名称的设备:例如“deviceName”。我正在使用 react-native-ble-plx。

import React, { Component } from 'react';
import {
  StyleSheet,
  Text,
  View,
  TouchableOpacity,
  ScrollView,
  FlatList,
  TextInput,
  Platform,
  Alert
} from 'react-native';
import { BleManager } from 'react-native-ble-plx';


export default class Main extends Component {
  constructor(props) {
          super(props);
          this.state={
              scaning:false,
              isConnected:false,
              text:'',
              writeData:'',
              receiveData:'',
              readData:'',
              bleManager: new BleManager(),
              data:[],
              isMonitoring:false,

          }
          this.bluetoothReceiveData = [];
          this.deviceMap = new Map();

  }



scan() {
  if(!this.state.scaning) {
    this.setState({scaning:true});
    this.deviceMap.clear();
    const { bleManager } = this.state;
    bleManager.startDeviceScan(null, null, async (error, device) => {
    console.log("scanning bluetooth...")

    if (device.name === "Proximity") {
        bleManager.connectToDevice(device.id, {
                autoconnect: true,
                timeout: BLUETOOTH_TIMEOUT,
                isConnected: true
            })
        // ............
    }
})
  }
}

disconnect(){
        bleManager.disconnect()
            .then(res=>{
                this.setState({data:[...this.deviceMap.values()],isConnected:false});
            })
            .catch(err=>{
                this.setState({data:[...this.deviceMap.values()],isConnected:false});
            })
}

render(){
  return(
    <View>
    <TouchableOpacity
                  activeOpacity={0.7}
                  style={[styles.buttonView,{marginHorizontal:10,height:40,alignItems:'center'}]}
                  onPress={this.state.isConnected?this.disconnect.bind(this):this.scan.bind(this)}>
                  <Text style={styles.buttonText}>{this.state.scaning?'Search':this.state.isConnected?'Disconnect Bluetooth':'Search Bluetooth'}</Text>
</TouchableOpacity>
    </View>
  );
}


}

const styles = StyleSheet.create({
    container: {
        flex: 1,
        backgroundColor:'white',
        marginTop:Platform.OS == 'ios'?20:0,
    },
    item:{
        flexDirection:'column',
        borderColor:'rgb(235,235,235)',
        borderStyle:'solid',
        borderBottomWidth:StyleSheet.hairlineWidth,
        paddingLeft:10,
        paddingVertical:8,
    },
    buttonView:{
        height:30,
        backgroundColor:'rgb(33, 150, 243)',
        paddingHorizontal:10,
        borderRadius:5,
        justifyContent:"center",
        alignItems:'center',
        alignItems:'flex-start',
        marginTop:10
    },
    buttonText:{
        color:"white",
        fontSize:12,
    },
    content:{
        marginTop:5,
        marginBottom:15,
    },
    textInput:{
        paddingLeft:5,
        paddingRight:5,
        backgroundColor:'white',
        height:50,
        fontSize:16,
        flex:1,
    },
})

此时我收到此错误:“undefined is not an object (evaluating 'b.default.startDeviceScan').

如何解决这个错误？你认为代码可以直接连接到设备吗？谢谢

Answer 1

您错误地导出了 BleManager。你必须像这样把它放在大括号之间:

import { BleManager } from 'react-native-ble-plx';

你也用错了 BleManager。你必须在某个地方实例化它，我习惯在状态下使用它，以确保我只有 1 个 BleManager 并像这样创建一个新的 BleManager 对象:

 constructor {
    ....
    this.state = {
      ....
      bleManager: new BleManager(),
      ....
    };

然后像这样使用 this.state.bleManager 而不是 BleManager:

const { bleManager } = this.state;
bleManager.startDeviceScan(...)