一、app目录下添加

implementation 'io.github.xmaihh:serialport:2.1.1'

1) 点击Sync Now更新依赖

2) AndroidManifest.xml文件添加读取设备信息权限

<uses-permission android:name="android.permission.READ_PHONE_STATE" />

二、 使用

1) 创建MySerialPort.java文件

package com.youlian.weight.serialport;

import android.content.Context;
import android.os.Handler;
import android.os.Looper;
import android.util.Log;

import java.io.IOException;
import java.util.Arrays;

import tp.xmaihh.serialport.SerialHelper;
import tp.xmaihh.serialport.bean.ComBean;
import tp.xmaihh.serialport.utils.ByteUtil;

public class MySerialPort {
    private SerialHelper serialHelper = null;
    private String Tag = "MySerialPort";
    private Handler handler;
    private boolean isHexType = true;
    private Context context;
    public MySerialPort(String port, Context context){
        this.context = context;
        serialHelper = new SerialHelper(port, 9600) {
            @Override
            protected void onDataReceived(ComBean paramComBean) {
//                String time = paramComBean.sRecTime;
                String rxText = new String(paramComBean.bRec);
                if (isHexType) {
                    //转成十六进制数据
                    rxText = ByteUtil.ByteArrToHex(paramComBean.bRec);
                }
//                Log.d(Tag,"收到消息："+rxText);
                handler = new Handler(Looper.getMainLooper());
                String finalRxText = rxText;
                handler.post(new Runnable() {
                    @Override
                    public void run() {
                        typeOperate(finalRxText);
                    }
                });
            }
        };
        serialHelper.setStopBits(1);  //设置停止位
        serialHelper.setDataBits(8);  //设置数据位
        serialHelper.setParity(0);      //设置校验位
        serialHelper.setFlowCon(0);    //设置流控
        try {
            serialHelper.open();
        }catch (IOException e){
            Log.e(Tag,"串口打开失败");
        }
    }

    /**
     * 返回指令判断
     * @param data
     */
    private void typeOperate(String data){
        Log.d(Tag,"返回数据：" + data);
    }

    /**
     * 发送byte[]
     * @param bOutArray
     */
    public void sendByte(byte[] bOutArray){
        Log.e(Tag,"发送byte[]："+ Arrays.toString(bOutArray));
        serialHelper.send(bOutArray);
    }

    /**
     * 发送Hex
     * @param sHex
     */
    public void sendHex(String sHex) {
        // Log.e(Tag, "发送Hex：" + sHex + ", 时间：" + getTime());
        serialHelper.sendHex(sHex);
    }

    /**
     * 发送ASCII
     * @param sTxt
     */
    public void sendTxt(String sTxt){
        Log.e(Tag,"发送ASCII："+sTxt);
        serialHelper.sendTxt(sTxt);
    }

    /**
     * 打开串口
     */
    public void open(){
        try {
            serialHelper.open();
        }catch (Exception e){
            Log.e(Tag,"串口打开失败");
        }
    }

    /**
     * 关闭串口
     */
    public void close(){
        serialHelper.close();
    }
}

2) 实例化

import com.you.weight.serialport.MySerialPort;

public static MySerialPort mySerialPort = null;

// /dev/ttyS3是你自己插的串口名称
mySerialPort = new MySerialPort("/dev/ttyS3", MainActivity.this);