第一次写博客，不知道说些什么，给大家拜个早年吧。
谷歌开源串口类serialPort-api
源码下载：冲冲冲
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界面效果图

布局文件

<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical">

    <TextView
        android:id="@+id/txt_comrecv"
        android:layout_width="0dp"
        android:layout_height="600dp"
        android:background="@android:drawable/editbox_background_normal"
        android:scrollbars="vertical"
        android:singleLine="false"
        android:textSize="24sp"
        app:layout_constraintHorizontal_bias="1.0"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toLeftOf="@+id/Ra_sidebar"
        app:layout_constraintTop_toTopOf="parent" />

    <LinearLayout
        android:id="@+id/la_center"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:padding="10dp"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/txt_comrecv">

        <Spinner
            android:id="@+id/Spin_Serial_port"
            android:layout_width="100dp"
            android:layout_height="50dp"
            android:layout_marginStart="20dp"
            android:background="#B5BDBC"
            android:dropDownWidth="150dp"
            android:spinnerMode="dropdown"
            android:theme="@style/spinnerHead"
            android:visibility="visible" />

        <Spinner
            android:id="@+id/Spin_Baudrate"
            android:layout_width="100dp"
            android:layout_height="50dp"
            android:layout_marginStart="20dp"
            android:background="#B5BDBC"
            android:dropDownWidth="150dp"
            android:entries="@array/Baud_rate"
            android:spinnerMode="dropdown"
            android:theme="@style/spinnerHead"
            android:visibility="visible" />

        <Button
            android:id="@+id/btn_open"
            android:layout_width="wrap_content"
            android:layout_height="70dp"
            android:layout_marginStart="20dp"
            android:text="打开串口"
            android:textSize="20dp"
            app:layout_constraintRight_toRightOf="parent"
            app:layout_constraintTop_toTopOf="parent" />


        <Button
            android:id="@+id/btn_Send_out"
            android:layout_width="100sp"
            android:layout_height="70dp"
            android:layout_marginStart="20dp"
            android:layout_alignParentBottom="true"
            android:text="发送"
            android:textSize="20dp" />


        <Button
            android:id="@+id/btn_close"
            android:layout_width="wrap_content"
            android:layout_height="70dp"
            android:layout_marginStart="20dp"
            android:text="关闭串口"
            android:textSize="20dp"
            app:layout_constraintRight_toRightOf="parent"
            app:layout_constraintTop_toTopOf="parent" />

        <CheckBox
            android:id="@+id/Cbx_automatic_Send_out"
            android:layout_width="wrap_content"
            android:layout_height="70dp"
            android:layout_marginStart="20dp"
            android:checked="false"
            android:text="自动发送"
            android:textSize="20dp"

            />

        <RadioGroup
            android:id="@+id/ra_style"
            android:layout_width="wrap_content"
            android:layout_marginStart="20dp"
            android:layout_height="wrap_content">

            <RadioButton
                android:id="@+id/Rdi_btn_Txt"
                android:layout_width="100sp"
                android:layout_height="wrap_content"
                android:checked="true"
                android:text="Txt"
                android:textSize="20dp"
                />

            <RadioButton
                android:id="@+id/Rdi_btn_Hex"
                android:layout_width="100sp"
                android:layout_height="wrap_content"
                android:layout_below="@+id/Rdi_btn_Txt"
                android:text="Hex"
                android:textSize="20dp" />

        </RadioGroup>


        <Button
            android:id="@+id/btn_clean"
            android:layout_width="100sp"
            android:layout_height="70dp"
            android:layout_marginStart="20dp"
            android:layout_below="@+id/ra_style"
            android:text="清除"
            android:textSize="20dp" />

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/txt_log"
            />


    </LinearLayout>


    <EditText
        android:id="@+id/Et_txt_input"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:background="@android:drawable/editbox_background_normal"
        android:gravity="left"
        android:text="COMA"
        android:textSize="20sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toLeftOf="@+id/Ra_sidebar"
        app:layout_constraintTop_toBottomOf="@+id/la_center" />


    <RelativeLayout
        android:id="@+id/Ra_sidebar"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent">



    </RelativeLayout>


</androidx.constraintlayout.widget.ConstraintLayout>

获取Android设备dev目录下的tty

    //获取串口
    static String[] getSerial_Ports_name() {
        List<String> Serial_Ports_number = new ArrayList<String>();
        String[] type = null;
        File file = new File("/dev/");
        File[] fs = file.listFiles();
        for (File f : fs) {
            if (f.getName().contains("tty")) {
                Serial_Ports_number.add(f.getName());
            }
        }
        type = Serial_Ports_number.toArray(new String[Serial_Ports_number.size()]);
        return type;
    }

Spinner选择串口与波特率

 //选择串口
        Spin_Serial_port = (Spinner) findViewById(R.id.Spin_Serial_port);
        ArrayAdapter<String> dataAdapter = new ArrayAdapter<String>(this,R.layout.my_spinner_item);
        String[] itemNames = getSerial_Ports_name();
        Arrays.sort(itemNames);//从大往小排序
        for (int i = 0; i < itemNames.length; i++) {
            dataAdapter.add(itemNames[i]);
        }
        Spin_Serial_port.setAdapter(dataAdapter);
        Spin_Serial_port.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
                String text = Spin_Serial_port.getItemAtPosition(position).toString();
                Serial_port_name = text;
            }

            @Override
            public void onNothingSelected(AdapterView<?> parent) {
            }
        });


        //选择波特率
        final Resources res = getResources();
        String[] city = res.getStringArray(R.array.Baud_rate);
        Spin_Baudrate = (Spinner) findViewById(R.id.Spin_Baudrate);
        final ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, R.layout.my_spinner_item, city);
        Spin_Baudrate.setAdapter(adapter);
        Spin_Baudrate.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
                String text = Spin_Baudrate.getItemAtPosition(position).toString();
                Spin_Baudrate_num = text;
            }

            @Override
            public void onNothingSelected(AdapterView<?> parent) {
            }
        });
        Spin_Baudrate.setSelection(1);  //从第一位开始算

RadioGroup切换Hex或Txt发送模式

  //选择发送模式(Txt/Hex)
        RadioGroup ra_style = (RadioGroup) findViewById(R.id.ra_style);
        ra_style.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
            @Override
            public void onCheckedChanged(RadioGroup group, int checkedId) {
                //isChecked 默认为true
                if (Rdi_btn_Txt.isChecked()) {
                    Et_txt_input.setText("COMA");
                    Log.e("发送Txt消息", "ischecked :" + Rdi_btn_Txt.isChecked());
                    sendtype = 0;
                } else {
                    sendtype = 1;
                    //限制Hex模式发送字符
                    Et_txt_input.setText("AA");
                    Log.e("发送Hex消息", "ischecked :" + Rdi_btn_Txt.isChecked());
                    Rdi_btn_Hex = (RadioButton) findViewById(R.id.Rdi_btn_Hex);
                    Rdi_btn_Hex.setOnClickListener(new OnClickListener() {
                        @Override
                        public void onClick(View v) {
                            Et_txt_input = (EditText) findViewById(R.id.Et_txt_input);
                            Et_txt_input.addTextChangedListener(new TextWatcher() {
                                @Override
                                public void beforeTextChanged(CharSequence s, int start, int count, int after) {
                                }

                                @Override
                                public void onTextChanged(CharSequence s, int start, int before, int count) {
                                    String limit = "";
                                    String regEx = "[^a-fA-F0-9]";
                                    Pattern p = Pattern.compile(regEx);
                                    Matcher m = p.matcher(limit);
                                    String str = m.replaceAll("").trim();
                                    if (!limit.equals(str)) {
                                        Et_txt_input.setText(str);
                                        Et_txt_input.setSelection(str.length());
                                    }
                                }

                                @Override
                                public void afterTextChanged(Editable s) {
                                }
                            });
                        }
                    });
                }
            }
        });

CheckBox勾选自动发送

        //选择自动发送
        Cbx_automatic_Send_out.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
            @Override
            public void onCheckedChanged(CompoundButton buttonView, final boolean isChecked) {
                //未打开串口并勾选自动发送时
                if (mySerialOperator.isOpen() == false) {
                    Log.e("请打开串口", "xxxxxxxxx");
                    String str = "请打开串口";
                    Toast.makeText(MainActivity.this, str, Toast.LENGTH_SHORT).show();
                    return;
                }
                //勾选自动发送
                if (Cbx_automatic_Send_out.isChecked()) {
                    Log.e("isChecked", "======\r" + isChecked);
                    Cbx_automatic_Send_out.setOnClickListener(new OnClickListener() {
                        @Override
                        public void onClick(View v) {
                            new Thread(new Runnable() {
                                volatile boolean exit = false;

                                @Override
                                public void run() {
                                    while (!exit) {
                                        //exit = true;
                                        if (!exit && mySerialOperator != null && mySerialOperator.isOpen()) {
                                            Log.e("开启自动发送", "");
                                            SimpleDateFormat dateformat = new SimpleDateFormat("[HH:mm:ss]");
                                            final String str1 = dateformat.format(System.currentTimeMillis());
                                            String txtToSend = Et_txt_input.getText().toString();
                                            if( sendtype == 0){
                                                aa += txtToSend.getBytes().length;
                                                //txt_log.setText(String.format("发%d收%d",aa,ss));
                                                mySerialOperator.send( txtToSend.getBytes() );
                                            }
                                            else{
                                                txtToSend.replace("\r", "" );
                                                txtToSend.replace("\n", "" );
                                                txtToSend.replace(" ", "" );

                                                if( txtToSend.length()%2 != 0)
                                                    txtToSend += "0";

                                                mySerialOperator.send( hexStringToBytes( txtToSend ) );
                                            }
                                            Scroll_to_bottom();
                                            //开启自动发送 500ms 刷新一次
                                            try {
                                                Thread.sleep(500);
                                            } catch (InterruptedException e) {
                                                e.printStackTrace();
                                            }
                                            //关闭自动发送
                                            if (!Cbx_automatic_Send_out.isChecked()) {
                                                Log.e("关闭自动发送", "close automatic send");
                                                break;
                                            }
                                        }

                                    }
                                }
                            }).start();
                        }
                    });
                }
            }
        });

输出消息定位在底部

    //输出信息定位在底部
    void Scroll_to_bottom() {
        int offset = txt_comrecv.getLineCount() * txt_comrecv.getLineHeight();
        if (offset > txt_comrecv.getHeight()) {
            txt_comrecv.scrollTo(0, offset - txt_comrecv.getHeight());
        }
    }

全部代码

import java.io.File;


import java.io.IOException;

import java.lang.reflect.Array;
import java.text.SimpleDateFormat;
import java.util.ArrayList;

import java.util.Arrays;
import java.util.List;
import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;


import android.content.Context;
import android.content.res.Resources;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.text.Editable;

import android.text.TextWatcher;
import android.text.method.ScrollingMovementMethod;
import android.util.Log;
import android.view.WindowManager;
import android.widget.*;
import android.app.Activity;

import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;

public class MainActivity extends Activity implements OnClickListener {

    Button btn_open;
    Button btn_clean;
    Button btn_close;
    Button btn_Send_out;
    TextView txt_comrecv;
    TextView txt_log;
    EditText Et_txt_input;
    Spinner Spin_Serial_port;
    Spinner Spin_Baudrate;
    CheckBox Cbx_automatic_Send_out;
    RadioButton Rdi_btn_Txt;
    RadioButton Rdi_btn_Hex;

    private SerialOperator mySerialOperator;


    String Spin_Baudrate_num;
    String Serial_port_name;
    int sendtype = 0;//发送类型 0 = 文本 1 = hex


    //获取串口
    static String[] getSerial_Ports_name() {
        List<String> Serial_Ports_number = new ArrayList<String>();
        String[] type = null;
        File file = new File("/dev/");
        File[] fs = file.listFiles();
        for (File f : fs) {
            if (f.getName().contains("tty")) {
                Serial_Ports_number.add(f.getName());
            }
        }
        type = Serial_Ports_number.toArray(new String[Serial_Ports_number.size()]);
        return type;
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {

        getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_ADJUST_PAN);
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        Cbx_automatic_Send_out = (CheckBox) findViewById(R.id.Cbx_automatic_Send_out);
        btn_Send_out = (Button) findViewById(R.id.btn_Send_out);
        btn_open = (Button) findViewById(R.id.btn_open);
        btn_clean = (Button) findViewById(R.id.btn_clean);
        btn_close = (Button) findViewById(R.id.btn_close);
        Et_txt_input = (EditText) findViewById(R.id.Et_txt_input);
        Rdi_btn_Txt = (RadioButton) findViewById(R.id.Rdi_btn_Txt);
        Rdi_btn_Hex = (RadioButton) findViewById(R.id.Rdi_btn_Hex);
        txt_log = (TextView) findViewById(R.id.txt_log);

        Cbx_automatic_Send_out.setOnClickListener(this);
        btn_Send_out.setOnClickListener(this);
        btn_open.setOnClickListener(this);
        btn_clean.setOnClickListener(this);
        btn_close.setOnClickListener(this);
        Rdi_btn_Txt.setOnClickListener(this);
        Rdi_btn_Hex.setOnClickListener(this);

        //侧边滑动条
        txt_comrecv = (TextView) this.findViewById(R.id.txt_comrecv);
        txt_comrecv.setMovementMethod(ScrollingMovementMethod.getInstance());


        //清除显示文本内容
        txt_comrecv = (TextView) findViewById(R.id.txt_comrecv);
        btn_clean.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                txt_comrecv.setText(null);

                ss = 0;
                aa = 0;
                txt_log.setText(String.format("发%d收%d",aa,ss));
            }
        });

        //选择串口
        Spin_Serial_port = (Spinner) findViewById(R.id.Spin_Serial_port);
        ArrayAdapter<String> dataAdapter = new ArrayAdapter<String>(this,R.layout.my_spinner_item);
        String[] itemNames = getSerial_Ports_name();
        Arrays.sort(itemNames);//从大往小排序
        for (int i = 0; i < itemNames.length; i++) {
            dataAdapter.add(itemNames[i]);
        }
        Spin_Serial_port.setAdapter(dataAdapter);
        Spin_Serial_port.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
                String text = Spin_Serial_port.getItemAtPosition(position).toString();
                Serial_port_name = text;
            }

            @Override
            public void onNothingSelected(AdapterView<?> parent) {
            }
        });


        //选择波特率
        final Resources res = getResources();
        String[] city = res.getStringArray(R.array.Baud_rate);
        Spin_Baudrate = (Spinner) findViewById(R.id.Spin_Baudrate);
        final ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, R.layout.my_spinner_item, city);
        Spin_Baudrate.setAdapter(adapter);
        Spin_Baudrate.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
                String text = Spin_Baudrate.getItemAtPosition(position).toString();
                Spin_Baudrate_num = text;
            }

            @Override
            public void onNothingSelected(AdapterView<?> parent) {
            }
        });
        Spin_Baudrate.setSelection(1);  //从第一位开始算

        mySerialOperator = new SerialOperator();

        //选择发送模式(Txt/Hex)
        RadioGroup ra_style = (RadioGroup) findViewById(R.id.ra_style);
        ra_style.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
            @Override
            public void onCheckedChanged(RadioGroup group, int checkedId) {
                //isChecked 默认为true
                if (Rdi_btn_Txt.isChecked()) {
                    Et_txt_input.setText("COMA");
                    Log.e("发送Txt消息", "ischecked :" + Rdi_btn_Txt.isChecked());
                    sendtype = 0;
                } else {
                    sendtype = 1;
                    //限制Hex模式发送字符
                    Et_txt_input.setText("AA");
                    Log.e("发送Hex消息", "ischecked :" + Rdi_btn_Txt.isChecked());
                    Rdi_btn_Hex = (RadioButton) findViewById(R.id.Rdi_btn_Hex);
                    Rdi_btn_Hex.setOnClickListener(new OnClickListener() {
                        @Override
                        public void onClick(View v) {
                            Et_txt_input = (EditText) findViewById(R.id.Et_txt_input);
                            Et_txt_input.addTextChangedListener(new TextWatcher() {
                                @Override
                                public void beforeTextChanged(CharSequence s, int start, int count, int after) {
                                }

                                @Override
                                public void onTextChanged(CharSequence s, int start, int before, int count) {
                                    String limit = "";
                                    String regEx = "[^a-fA-F0-9]";
                                    Pattern p = Pattern.compile(regEx);
                                    Matcher m = p.matcher(limit);
                                    String str = m.replaceAll("").trim();
                                    if (!limit.equals(str)) {
                                        Et_txt_input.setText(str);
                                        Et_txt_input.setSelection(str.length());
                                    }
                                }

                                @Override
                                public void afterTextChanged(Editable s) {
                                }
                            });
                        }
                    });
                }
            }
        });

        //选择自动发送
        Cbx_automatic_Send_out.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
            @Override
            public void onCheckedChanged(CompoundButton buttonView, final boolean isChecked) {
                //未打开串口并勾选自动发送时
                if (mySerialOperator.isOpen() == false) {
                    Log.e("请打开串口", "xxxxxxxxx");
                    String str = "请打开串口";
                    Toast.makeText(MainActivity.this, str, Toast.LENGTH_SHORT).show();
                    return;
                }
                //勾选自动发送
                if (Cbx_automatic_Send_out.isChecked()) {
                    Log.e("isChecked", "======\r" + isChecked);
                    Cbx_automatic_Send_out.setOnClickListener(new OnClickListener() {
                        @Override
                        public void onClick(View v) {
                            new Thread(new Runnable() {
                                volatile boolean exit = false;

                                @Override
                                public void run() {
                                    while (!exit) {
                                        //exit = true;
                                        if (!exit && mySerialOperator != null && mySerialOperator.isOpen()) {
                                            Log.e("开启自动发送", "");
                                            SimpleDateFormat dateformat = new SimpleDateFormat("[HH:mm:ss]");
                                            final String str1 = dateformat.format(System.currentTimeMillis());
                                            String txtToSend = Et_txt_input.getText().toString();
                                            if( sendtype == 0){
                                                aa += txtToSend.getBytes().length;
                                                //txt_log.setText(String.format("发%d收%d",aa,ss));
                                                mySerialOperator.send( txtToSend.getBytes() );
                                            }
                                            else{
                                                txtToSend.replace("\r", "" );
                                                txtToSend.replace("\n", "" );
                                                txtToSend.replace(" ", "" );

                                                if( txtToSend.length()%2 != 0)
                                                    txtToSend += "0";

                                                mySerialOperator.send( hexStringToBytes( txtToSend ) );
                                            }
                                            Scroll_to_bottom();
                                            //开启自动发送 500ms 刷新一次
                                            try {
                                                Thread.sleep(500);
                                            } catch (InterruptedException e) {
                                                e.printStackTrace();
                                            }
                                            //关闭自动发送
                                            if (!Cbx_automatic_Send_out.isChecked()) {
                                                Log.e("关闭自动发送", "close automatic send");
                                                break;
                                            }
                                        }

                                    }
                                }
                            }).start();
                        }
                    });
                }
            }
        });
    }

    @Override
    protected void onStop() {
        super.onStop();
        if (mySerialOperator != null) {
            mySerialOperator.stopSend();
            mySerialOperator.close();
            mySerialOperator = null;
        }
    }

    public static byte[] hexStringToBytes(String hexString) {
        if (hexString == null || hexString.equals("")) {
            return null;
        }
        hexString = hexString.toUpperCase();
        int length = hexString.length() / 2;
        char[] hexChars = hexString.toCharArray();
        byte[] d = new byte[length];
        for (int i = 0; i < length; i++) {
            int pos = i * 2;
            d[i] = (byte) (charToByte(hexChars[pos]) << 4 | charToByte(hexChars[pos + 1]));

        }
        return d;
    }
    private static byte charToByte(char c) {
        return (byte) "0123456789ABCDEF".indexOf(c);
    }


    //输出信息定位在底部
    void Scroll_to_bottom() {
        int offset = txt_comrecv.getLineCount() * txt_comrecv.getLineHeight();
        if (offset > txt_comrecv.getHeight()) {
            txt_comrecv.scrollTo(0, offset - txt_comrecv.getHeight());
        }
    }

    long ss;
    long aa;

    Handler mHandler = new Handler() {
        @Override
        public void handleMessage(Message msg) {
            super.handleMessage(msg);
            switch (msg.what) {
                case 0:
                    //拿到数据,完成主界面更新
//              String data = (String)msg.obj;
                    byte[] bytes = (byte[]) msg.obj;
                    int arg1 = msg.arg1;
                    String strRecv ;
                    if(sendtype == 0){
                        strRecv = new String(bytes,0,arg1);
                    }else{
                        strRecv = bytes2HexString(bytes,arg1);
                        StringBuilder stringBuilder2=new StringBuilder(strRecv);

                        for(int i = strRecv.length(); i>0; i--){
                            if(i%2 ==0 )
                                stringBuilder2.insert(i," ");
                        }

                        strRecv = stringBuilder2.toString();
                    }

                    SimpleDateFormat dateformat = new SimpleDateFormat("[HH:mm:ss]");
                    final String Send = dateformat.format(System.currentTimeMillis());


//              txt_recv.setText(data);

                    StringBuilder sMsg = new StringBuilder();
                    sMsg.append("\r\n");
                    sMsg.append(Send+ strRecv);

                    txt_comrecv.append(sMsg);
                    ss += arg1;
                    txt_log.setText(String.format("发%d收%d",aa,ss));
                    //txt_log.setText(Long.toString(ss));
                    Scroll_to_bottom();//滚动到底部

                    break;
                default:
                    break;
            }
        }

    };

    public static String bytes2HexString(byte[] b, int len) {
        String ret = "";
        for (int i = 0; i < len; i++) {
            String hex = Integer.toHexString(b[ i ] & 0xFF);
            if (hex.length() == 1) {
                hex = '0' + hex;
            }
            ret += hex.toUpperCase();
        }
        return ret;
    }
    @Override
    public void onClick(View v) {

        //打开串口 发送消息 关闭串口
        switch (v.getId()) {

            //打开串口
            case R.id.btn_open:

                if (mySerialOperator != null) {
                    mySerialOperator.close();
                    mySerialOperator = null;
                }
                mySerialOperator = new SerialOperator();
                mySerialOperator.setBaudRate(Spin_Baudrate_num);
                mySerialOperator.setPort("/dev/" + Serial_port_name);
                mySerialOperator.setHandler(mHandler);
                Log.e("打开串口", "open\r");

                Toast.makeText(MainActivity.this, "打开串口成功", Toast.LENGTH_SHORT).show();
                try {
                    mySerialOperator.open();
                } catch (SecurityException | IOException e) {
                    e.printStackTrace();
                }
                break;

            //发送数据
            case R.id.btn_Send_out:

                if (mySerialOperator == null || mySerialOperator.isOpen() == false) {
                    String str = "请先打开串口";
                    Toast.makeText(MainActivity.this, str, Toast.LENGTH_SHORT).show();
                    return;
                }

                String txtToSend = Et_txt_input.getText().toString();
                if( txtToSend == null || txtToSend.isEmpty() )
                {
                    Toast.makeText(MainActivity.this, "输入内容再点发送", Toast.LENGTH_SHORT).show();
                    return;
                }

                if( sendtype == 0){
                    aa += txtToSend.getBytes().length;
                    txt_log.setText(String.format("发%d收%d",aa,ss));
                    mySerialOperator.send( txtToSend.getBytes() );
                }
                else{
                    txtToSend.replace("\r", "" );
                    txtToSend.replace("\n", "" );
                    txtToSend.replace(" ", "" );

                    if( txtToSend.length()%2 != 0)
                        txtToSend += "0";
                    aa += hexStringToBytes(txtToSend).length;
                    txt_log.setText(String.format("发%d收%d",aa,ss));
                    mySerialOperator.send( hexStringToBytes( txtToSend ) );

                }
                break;

            //关闭串口
            case R.id.btn_close:
                String close = "关闭串口";
                if (mySerialOperator != null) {
                    mySerialOperator.stopSend();
                    mySerialOperator.close();
                    mySerialOperator = null;
                    Log.e("关闭串口", "close coms");
                    Toast.makeText(MainActivity.this, close, Toast.LENGTH_SHORT).show();
                }
                break;
            default:
                break;
        }
    }
}

两个工具类

package com.idean.tools;

/**
 * @author Tim
 * @����D�Q����
 */
public class ConvertedType {
	//-------------------------------------------------------
	// �ж�������ż����λ���㣬���һλ��1��Ϊ������Ϊ0��ż��
    /**
     * @param num
     * @return
     */
    static public int isOdd(int num)
	{
		return num & 0x1;
	}
    //-------------------------------------------------------
    static public int HexToInt(String inHex)//Hex�ַ���תint
    {
    	return Integer.parseInt(inHex, 16);
    }
    //-------------------------------------------------------
    static public byte HexToByte(String inHex)//Hex�ַ���תbyte
    {

    	return (byte)Integer.parseInt(inHex,16);
    }
    //-------------------------------------------------------
    static public String Byte2Hex(Byte inByte)//1�ֽ�ת2��Hex�ַ�
    {
    	return String.format("%02x", inByte).toUpperCase();
    }
    //-------------------------------------------------------
	static public String ByteArrToHex(byte[] inBytArr)//�ֽ�����תתhex�ַ���
	{
		StringBuilder strBuilder=new StringBuilder();
		int j=inBytArr.length;
		for (int i = 0; i < j; i++)
		{
			strBuilder.append(Byte2Hex(inBytArr[i]));
			strBuilder.append(" ");
		}
		return strBuilder.toString(); 
	}
  //-------------------------------------------------------
    static public String ByteArrToHex(byte[] inBytArr,int offset,int byteCount)//�ֽ�����תתhex�ַ�������ѡ����
	{
    	StringBuilder strBuilder=new StringBuilder();
		int j=byteCount;
		for (int i = offset; i < j; i++)
		{
			strBuilder.append(Byte2Hex(inBytArr[i]));
		}
		return strBuilder.toString();
	}
	//-------------------------------------------------------
	//תhex�ַ���ת�ֽ�����
    static public byte[] HexToByteArr(String inHex)//hex�ַ���ת�ֽ�����
	{
		int hexlen = inHex.length();
		byte[] result;
		if (isOdd(hexlen)==1)
		{//����
			hexlen++;
			result = new byte[(hexlen/2)];
			inHex="0"+inHex;
		}else {//ż��
			result = new byte[(hexlen/2)];
		}
	    int j=0;
		for (int i = 0; i < hexlen; i+=2)
		{
			result[j]=HexToByte(inHex.substring(i,i+2).trim());
			j++;
		}
	    return result; 
	}
}

package com.idean.tools;
import android.util.Log;

public class Debug {

	public boolean isShow = false;
	public String showLog;
	public static final boolean DEBUG_VESION = true;
	public static final boolean RELEASE_VESION = false;
	public static final int ERROR = 0;
	public static final int WARN = 1;
	public static final int INFO = 2;
	public static final int DEBUG = 3; 
	public static final int VERBOSE = 4;
	public Debug() {
	}
	
	/**
	 * @param isShow
	 * @param showLog
	 */
	public Debug(boolean isShow, String showLog) {
		this.isShow = isShow;
		this.showLog = showLog;
	}

	public boolean isShow() {
		return isShow;
	}
	public void setShow(boolean isShow) {
		this.isShow = isShow;
	}
	public String getShowLog() {
		return showLog;
	}
	public void setShowLog(String showLog) {
		this.showLog = showLog;
	}

	
	public static void showLog(boolean isRelaseVersion,String tag,String log,int level){
		
		if (isRelaseVersion) {
			switch (level) {
			case ERROR:
				Log.e(tag, log);
				break;
			case WARN:
				Log.w(tag, log);
				break;
			case INFO:
				Log.i(tag, log);
				break;
			case DEBUG:
				Log.d(tag, log);
				break;
			default:
				Log.v(tag, log);
				break;
			}
		}
	}
	
	
}

注意

未做打开串口失败的处理，每次点击打开串口都会弹出一个Toast，实际上串口并未打开。

本文地址：https://blog.csdn.net/weixin_45401264/article/details/107876116