Android 串口通信

Android串口通信可以實作設備與設備之間通過設備線連接進行資料（訊息）傳遞
（一）匯入so庫

（二）在moudle的build中添加jniLibs

buildTypes {
        sourceSets {
            main { jni.srcDirs = [] }
        }
    }

（三）添加Google的SerialPort
添加的是Google的所以必須創建android_serialport_api包
如需要更改SerialPort、SerialPortFinder位置需要重新生成so庫

（四）創建串口通信工具類SerialPortUtils

package com.demo.serialport;

import android.util.Log;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import android_serialport_api.SerialPort;

/**
 * @author renquan
 */

public class SerialPortUtils {

    private final String TAG = "SerialPortUtils";
//    private String path = "/dev/ttyS1";
//    private int baudrate = 9600;
    public boolean serialPortStatus = false; //是否打開串口標志
    public String data_;
    public boolean threadStatus; //執行緒狀態，為了安全終止執行緒

    public SerialPort serialPort = null;
    public InputStream inputStream = null;
    public OutputStream outputStream = null;
    public ChangeTool changeTool = new ChangeTool();


    /**
     * 打開串口
     * @return serialPort串口物件
     */
    public SerialPort openSerialPort(String path,int baudrate){
        try {
            serialPort = new SerialPort(new File(path),baudrate,0);
            this.serialPortStatus = true;
            threadStatus = false; //執行緒狀態

            //獲取打開的串口中的輸入輸出流，以便于串口資料的收發
            inputStream = serialPort.getInputStream();
            outputStream = serialPort.getOutputStream();

            new ReadThread().start(); //開始執行緒監控是否有資料要接收
        } catch (IOException e) {
            Log.e(TAG, "openSerialPort: 打開串口例外：" + e.toString());
            return serialPort;
        }
        Log.d(TAG, "openSerialPort: 打開串口");
        return serialPort;
    }

    /**
     * 關閉串口
     */
    public void closeSerialPort(){
        try {
            inputStream.close();
            outputStream.close();

            this.serialPortStatus = false;
            this.threadStatus = true; //執行緒狀態
            serialPort.close();
        } catch (IOException e) {
            Log.e(TAG, "closeSerialPort: 關閉串口例外："+e.toString());
            return;
        }
        Log.d(TAG, "closeSerialPort: 關閉串口成功");
    }

    /**
     * 發送串口指令（字串）
     * @param data String資料指令
     */
    public void sendSerialPort(String data){
        Log.d(TAG, "sendSerialPort: 發送資料");

        try {
            byte[] sendData = data.getBytes(); //string轉byte[]
            this.data_ = new String(sendData); //byte[]轉string
            if (sendData.length > 0) {
                outputStream.write(sendData);
                outputStream.write('\n');
                //outputStream.write('\r'+'\n');
                outputStream.flush();
                Log.d(TAG, "sendSerialPort: 串口資料發送成功");
            }
        } catch (IOException e) {
            Log.e(TAG, "sendSerialPort: 串口資料發送失敗："+e.toString());
        }

    }

    /**
     * 單開一執行緒，來讀資料
     */
    private class ReadThread extends Thread{
        @Override
        public void run() {
            super.run();
            //判斷行程是否在運行，更安全的結束行程
            while (!threadStatus){
                Log.d(TAG, "進入執行緒run");
                //64   1024
                byte[] buffer = new byte[64];
                int size; //讀取資料的大小
                try {
                    size = inputStream.read(buffer);
                    if (size > 0){
                        Log.d(TAG, "run: 接收到了資料：" + changeTool.ByteArrToHex(buffer));
                        Log.d(TAG, "run: 接收到了資料大小：" + String.valueOf(size));
                        onDataReceiveListener.onDataReceive(buffer,size);
                    }
                } catch (IOException e) {
                    Log.e(TAG, "run: 資料讀取例外：" +e.toString());
                }
            }

        }
    }

    //資料回呼
    public OnDataReceiveListener onDataReceiveListener = null;
    public static interface OnDataReceiveListener {
        public void onDataReceive(byte[] buffer, int size);
    }
    public void setOnDataReceiveListener(OnDataReceiveListener dataReceiveListener) {
        onDataReceiveListener = dataReceiveListener;
    }

}

package com.demo.serialport;

/**
 * @author renquan
 */

public class ChangeTool {

    /**
     * byte陣列轉16進制字串
     *
     * @param bytes byte陣列
     * @return 16進制字串
     */
    public String ByteArrToHex(byte[] bytes) {
        String strHex;
        StringBuilder sb = new StringBuilder();
        for (byte aByte : bytes) {
            strHex = Integer.toHexString(aByte & 0xFF);
            sb.append(" ").append((strHex.length() == 1) ? "0" : "").append(strHex); // 每個位元組由兩個字符表示，位數不夠，高位補0
        }
        return sb.toString().trim();
    }

    /**
     * byte位元組轉int
     *
     * @param b byte位元組
     * @return int
     */
    public static int byteToInt(byte b) {
        int x = b & 0xff;
        if (x == 127) {
            return 0;
        }
        return x;
    }
}

package com.demo.serialport;

import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;

import androidx.appcompat.app.AppCompatActivity;

/**
 * @author renquan
 */

public class MainActivity extends AppCompatActivity implements View.OnClickListener {
    private EditText mMessage;
    private Button mOpen;
    private Button mSend;
    private Button mClose;
    private SerialPortUtils serialPortUtils;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        init();


        //串口資料監聽事件
        serialPortUtils.setOnDataReceiveListener(new SerialPortUtils.OnDataReceiveListener() {
            @Override
            public void onDataReceive(byte[] buffer, int size) {
                Log.d("TAG", "進入資料監聽事件中，，，" + new String(buffer));

            }
        });

    }

    private void init() {
        initView();
        serialPortUtils = new SerialPortUtils();
    }

    private void initView() {
        mMessage = (EditText) findViewById(R.id.message);
        mOpen = (Button) findViewById(R.id.open);
        mOpen.setOnClickListener(this);
        mSend = (Button) findViewById(R.id.send);
        mSend.setOnClickListener(this);
        mClose = (Button) findViewById(R.id.close);
        mClose.setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {
        switch (v.getId()) {
            case R.id.open:
                // TODO 20/12/28
                serialPortUtils.openSerialPort("/dev/ttyS9",9600);
                break;
            case R.id.send:
                // TODO 20/12/28
                serialPortUtils.sendSerialPort(mSend.getText().toString());
                break;
            case R.id.close:
                serialPortUtils.closeSerialPort();
                // TODO 20/12/28
                break;
            default:
                break;
        }
    }
}

Demo——github地址