引言：
最近项目用到了串口通信功能,刚好写一篇文章来记录一下.
为什么学习Android串口通信：
- 现在,对于很多公司而言，Android主板与各种传感器和智能设备之间通信是很常见的事情了,那么安卓开发中,串口通信就是必须学习的事情了!
- Google出品，必属精品。Android串口通信的源代码是Google公司在2011年开源的Google官方源代码
集成串口通信：
一 、新建库项目导入so库
二 、 配置Gradle文件：基本没啥可配置的
前置工作就这么完成了....
Google串口代码分析之SerialPort类
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package android_serialport_api;
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import android.util.Log;
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import java.io.File;
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import java.io.FileDescriptor;
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import java.io.FileInputStream;
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import java.io.FileOutputStream;
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import java.io.IOException;
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import java.io.InputStream;
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import java.io.OutputStream;
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/**
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* Google官方代码
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* 此类的作用为，JNI的调用，用来加载.so文件的
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* 获取串口输入输出流
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*/
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public
class SerialPort {
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private
static
final String TAG =
"SerialPort";
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/*
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* Do not remove or rename the field mFd: it is used by native method
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* close();
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*/
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private FileDescriptor mFd;
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private FileInputStream mFileInputStream;
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private FileOutputStream mFileOutputStream;
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public SerialPort(File device, int baudrate, int flags)
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throws SecurityException, IOException {
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/* Check access permission */
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if (!device.canRead() || !device.canWrite()) {
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try {
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/* Missing read/write permission, trying to chmod the file */
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Process su;
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su = Runtime.getRuntime().exec(
"/system/bin/su");
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String cmd =
"chmod 666 " + device.getAbsolutePath() +
"\n"
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+
"exit\n";
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su.getOutputStream().write(cmd.getBytes());
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if ((su.waitFor() !=
0) || !device.canRead()
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|| !device.canWrite()) {
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throw
new SecurityException();
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}
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}
catch (Exception e) {
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e.printStackTrace();
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throw
new SecurityException();
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}
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}
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Log.v(TAG,
".\n********************************\nfile:" + device.getAbsolutePath() +
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"\nbaudrate:" + baudrate +
"\nflags:" + flags +
"\n********************************");
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mFd = open(device.getAbsolutePath(), baudrate, flags);
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if (mFd ==
null) {
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Log.e(TAG,
"native open returns null");
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throw
new IOException();
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}
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Log.v(TAG,
"open:" + mFd);
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mFileInputStream =
new FileInputStream(mFd);
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mFileOutputStream =
new FileOutputStream(mFd);
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}
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// Getters and setters
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public InputStream getInputStream() {
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return mFileInputStream;
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}
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public OutputStream getOutputStream() {
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return mFileOutputStream;
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}
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-
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// JNI
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private native static FileDescriptor open(String path, int baudrate,
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int flags);
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public native void close();
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static {
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System.out.println(
"==============================");
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System.loadLibrary(
"serial_port");
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System.out.println(
"********************************");
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}
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}
一：类作用及介绍
通过打开JNI的调用，打开串口。获取串口通信中的输入输出流，通过操作IO流，达到能够利用串口接收数据和发送数据的目的
A : 开启串口的方法：private native static FileDescriptor open(String path, int baudrate,int flags)
- path：为串口的物理地址，一般硬件工程师都会告诉你的例如ttyS0、ttyS1等，或者通过SerialPortFinder类去寻找得到可用的串口地址。
- baudrate：波特率，与外接设备一致
- flags：设置为0，原因较复杂,有兴趣的可以自己去研究一下
B : IO流
获取了输入输出流以后就可以对流进行操作了。
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package com.seriallibrary.myserialport;
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import android.util.Log;
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-
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import android_serialport_api.SerialPort;
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import java.io.File;
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import java.io.IOException;
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import java.io.InputStream;
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import java.io.OutputStream;
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/**
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* @author by AllenJ on 2018/4/20.
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* <p>
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* 通过串口用于接收或发送数据
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*/
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public
class SerialPortUtil {
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private SerialPort serialPort =
null;
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private InputStream inputStream =
null;
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private OutputStream outputStream =
null;
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private ReceiveThread mReceiveThread =
null;
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private
boolean isStart =
false;
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private SerialListen mSerialListen;
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/**
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* 打开串口，接收数据
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* 通过串口，接收单片机发送来的数据
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*/
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public void openSerialPort(String path, int baudrate, int flags) {
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try {
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serialPort =
new SerialPort(
new File(path), baudrate, flags);
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//调用对象SerialPort方法，获取串口中"读和写"的数据流
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inputStream = serialPort.getInputStream();
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outputStream = serialPort.getOutputStream();
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isStart =
true;
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}
catch (IOException e) {
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e.printStackTrace();
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}
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getSerialPort();
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}
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public void setSerialListen(SerialListen vSerialListen) {
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mSerialListen = vSerialListen;
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}
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/**
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* 关闭串口
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* 关闭串口中的输入输出流
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*/
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public void closeSerialPort() {
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Log.i(
"test",
"关闭串口");
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try {
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if (inputStream !=
null) {
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inputStream.close();
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}
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if (outputStream !=
null) {
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outputStream.close();
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}
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isStart =
false;
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}
catch (IOException e) {
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e.printStackTrace();
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}
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}
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/**
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* 发送数据
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* 通过串口，发送数据到单片机
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*
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* @param data 要发送的数据
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*/
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public void sendSerialPort(String data) {
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try {
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byte[] sendData = DataUtils.HexToByteArr(data);
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outputStream.write(sendData);
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outputStream.flush();
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}
catch (IOException e) {
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e.printStackTrace();
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}
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}
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private void getSerialPort() {
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if (mReceiveThread ==
null) {
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mReceiveThread =
new ReceiveThread();
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}
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try {
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mReceiveThread.start();
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}
catch (Exception e) {
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e.printStackTrace();
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}
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}
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/**
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* 接收串口数据的线程
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*/
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private
class ReceiveThread extends Thread {
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@Override
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public void run() {
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super.run();
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//条件判断，只要条件为true，则一直执行这个线程
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while (isStart) {
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if (inputStream ==
null) {
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return;
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}
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byte[] readData =
new
byte[
1024];
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try {
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int size = inputStream.read(readData);
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if (size >
0) {
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String readString = DataUtils.ByteArrToHex(readData,
0, size);
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if (mSerialListen !=
null) {
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mSerialListen.getSerial(readData, readString);
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}
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}
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}
catch (IOException e) {
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e.printStackTrace();
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}
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}
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}
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}
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}
SerialListen
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package com.seriallibrary.myserialport;
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public
interface
SerialListen {
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void getSerial(byte[] bytes,String string);
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}
串口数据转换工具类 DataUtils
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package com.seriallibrary.myserialport;
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import java.util.ArrayList;
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import java.util.
List;
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/**
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* 串口数据转换工具类
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* Created by Administrator on 2016/6/2.
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*/
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public
class DataUtils {
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//-------------------------------------------------------
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// 判断奇数或偶数，位运算，最后一位是1则为奇数，为0是偶数
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public
static
int isOdd(
int num) {
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return num &
1;
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}
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//-------------------------------------------------------
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//Hex字符串转int
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public
static
int HexToInt(
String inHex) {
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return
Integer.parseInt(inHex,
16);
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}
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public
static
String IntToHex(
int intHex){
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return
Integer.toHexString(intHex);
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}
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//-------------------------------------------------------
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//Hex字符串转byte
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public
static byte HexToByte(
String inHex) {
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return (byte)
Integer.parseInt(inHex,
16);
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}
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//-------------------------------------------------------
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//1字节转2个Hex字符
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public
static
String Byte2Hex(Byte inByte) {
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return
String.format(
"%02x",
new
Object[]{inByte}).toUpperCase();
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}
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//-------------------------------------------------------
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//字节数组转转hex字符串
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public
static
String ByteArrToHex(byte[] inBytArr) {
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StringBuilder strBuilder =
new StringBuilder();
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for (byte valueOf : inBytArr) {
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strBuilder.append(Byte2Hex(Byte.valueOf(valueOf)));
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strBuilder.append(
" ");
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}
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return strBuilder.toString();
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}
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//-------------------------------------------------------
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//字节数组转转hex字符串，可选长度
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public
static
String ByteArrToHex(byte[] inBytArr,
int offset,
int byteCount) {
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StringBuilder strBuilder =
new StringBuilder();
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int j = byteCount;
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for (
int i = offset; i < j; i++) {
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strBuilder.append(Byte2Hex(Byte.valueOf(inBytArr[i])));
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}
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return strBuilder.toString();
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}
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//-------------------------------------------------------
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//转hex字符串转字节数组
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public
static byte[] HexToByteArr(
String inHex) {
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byte[] result;
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int hexlen = inHex.length();
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if (isOdd(hexlen) ==
1) {
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hexlen++;
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result =
new byte[(hexlen /
2)];
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inHex =
"0" + inHex;
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}
else {
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result =
new byte[(hexlen /
2)];
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}
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int j =
0;
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for (
int i =
0; i < hexlen; i +=
2) {
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result[j] = HexToByte(inHex.substring(i, i +
2));
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j++;
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}
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return result;
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}
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/**
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* 按照指定长度切割字符串
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*
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* @param inputString 需要切割的源字符串
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* @param length 指定的长度
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* @return
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*/
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public
static
List<
String> getDivLines(
String inputString,
int length) {
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List<
String> divList =
new ArrayList<>();
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int remainder = (inputString.length()) % length;
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// 一共要分割成几段
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int number = (
int) Math.floor((inputString.length()) / length);
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for (
int index =
0; index < number; index++) {
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String childStr = inputString.substring(index * length, (index +
1) * length);
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divList.add(childStr);
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}
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if (remainder >
0) {
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String cStr = inputString.substring(number * length, inputString.length());
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divList.add(cStr);
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}
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return divList;
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}
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/**
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* 计算长度，两个字节长度
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*
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* @param val value
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* @return 结果
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*/
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public
static
String twoByte(
String val) {
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if (val.length() >
4) {
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val = val.substring(
0,
4);
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}
else {
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int l =
4 - val.length();
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for (
int i =
0; i < l; i++) {
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val =
"0" + val;
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}
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}
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return val;
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}
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/**
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* 校验和
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*
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* @param cmd 指令
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* @return 结果
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*/
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public
static
String sum(
String cmd) {
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List<
String> cmdList = DataUtils.getDivLines(cmd,
2);
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int sumInt =
0;
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for (
String c : cmdList) {
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sumInt += DataUtils.HexToInt(c);
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}
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String sum = DataUtils.IntToHex(sumInt);
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sum = DataUtils.twoByte(sum);
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cmd += sum;
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return cmd.toUpperCase();
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}
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}
主要的类就是这么几个,一个so加载类,一个串口操作工具类,一个数据解析工具类,一个回调接口,主要是用来封装串口的!
调用方式: 主要分为实例化工具类,打开串口,设置接口回调方法,在需要使用串口的时候发送数据,数据是String格式的,在SerialPortUtil里面会自动转化,只需要使用即可
整个代码我已经封装了一个aar包,可以导入直接使用,如果需要免费下载!
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源代码Here：
- Github下载地址：！------> SerialPortの源代码
- CSDN下载地址：！------> SerialPortの源代码
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转载：https://blog.csdn.net/qq_36333309/article/details/111310038
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