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将 SerialPort.c 放入 src/main/cpp
目录中。
#include <termios.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <string.h>
#include <jni.h>
#include "android/log.h"
static const char *TAG="serial_port";
#define LOGI(fmt, args...) __android_log_print(ANDROID_LOG_INFO, TAG, fmt, ##args)
#define LOGD(fmt, args...) __android_log_print(ANDROID_LOG_DEBUG, TAG, fmt, ##args)
#define LOGE(fmt, args...) __android_log_print(ANDROID_LOG_ERROR, TAG, fmt, ##args)
/*
* Class: android_serialport_SerialPort
* Method: open
* Signature: (Ljava/lang/String;II)Ljava/io/FileDescriptor;
*/
static speed_t getBaudrate(jint baudrate)
{
switch(baudrate) {
case 0: return B0;
case 50: return B50;
case 75: return B75;
case 110: return B110;
case 134: return B134;
case 150: return B150;
case 200: return B200;
case 300: return B300;
case 600: return B600;
case 1200: return B1200;
case 1800: return B1800;
case 2400: return B2400;
case 4800: return B4800;
case 9600: return B9600;
case 19200: return B19200;
case 38400: return B38400;
case 57600: return B57600;
case 115200: return B115200;
case 230400: return B230400;
case 460800: return B460800;
case 500000: return B500000;
case 576000: return B576000;
case 921600: return B921600;
case 1000000: return B1000000;
case 1152000: return B1152000;
case 1500000: return B1500000;
case 2000000: return B2000000;
case 2500000: return B2500000;
case 3000000: return B3000000;
case 3500000: return B3500000;
case 4000000: return B4000000;
default: return -1;
}
}
/*
* Class: android_serialport_SerialPort
* Method: open
* Signature: (Ljava/lang/String;II)Ljava/io/FileDescriptor;
*/
JNIEXPORT jobject JNICALL Java_com_test_serialtool_SerialPort_open
(JNIEnv *env, jclass thiz, jstring path, jint baudrate, jint flags)
{
int fd;
speed_t speed;
jobject mFileDescriptor;
/* Check arguments */
{
speed = getBaudrate(baudrate);
if (speed == -1) {
/* TODO: throw an exception */
LOGE("Invalid baudrate");
return NULL;
}
}
/* Opening device */
{
jboolean iscopy;
const char *path_utf = (*env)->GetStringUTFChars(env, path, &iscopy);
LOGD("Opening serial port %s with flags 0x%x", path_utf, O_RDWR | flags);
fd = open(path_utf, O_RDWR | flags);
LOGD("open() fd = %d", fd);
(*env)->ReleaseStringUTFChars(env, path, path_utf);
if (fd == -1)
{
/* Throw an exception */
LOGE("Cannot open port");
/* TODO: throw an exception */
return NULL;
}
}
/* Configure device */
{
struct termios cfg;
LOGD("Configuring serial port");
if (tcgetattr(fd, &cfg))
{
LOGE("tcgetattr() failed");
close(fd);
/* TODO: throw an exception */
return NULL;
}
cfmakeraw(&cfg);
cfsetispeed(&cfg, speed);
cfsetospeed(&cfg, speed);
if (tcsetattr(fd, TCSANOW, &cfg))
{
LOGE("tcsetattr() failed");
close(fd);
/* TODO: throw an exception */
return NULL;
}
}
/* Create a corresponding file descriptor */
{
jclass cFileDescriptor = (*env)->FindClass(env, "java/io/FileDescriptor");
jmethodID iFileDescriptor = (*env)->GetMethodID(env, cFileDescriptor, "<init>", "()V");
jfieldID descriptorID = (*env)->GetFieldID(env, cFileDescriptor, "descriptor", "I");
mFileDescriptor = (*env)->NewObject(env, cFileDescriptor, iFileDescriptor);
(*env)->SetIntField(env, mFileDescriptor, descriptorID, (jint)fd);
}
return mFileDescriptor;
}
/*
* Class: cedric_serial_SerialPort
* Method: close
* Signature: ()V
*/
JNIEXPORT void JNICALL Java_com_test_serialtool_SerialPort_close
(JNIEnv *env, jobject thiz)
{
jclass SerialPortClass = (*env)->GetObjectClass(env, thiz);
jclass FileDescriptorClass = (*env)->FindClass(env, "java/io/FileDescriptor");
jfieldID mFdID = (*env)->GetFieldID(env, SerialPortClass, "mFd", "Ljava/io/FileDescriptor;");
jfieldID descriptorID = (*env)->GetFieldID(env, FileDescriptorClass, "descriptor", "I");
jobject mFd = (*env)->GetObjectField(env, thiz, mFdID);
jint descriptor = (*env)->GetIntField(env, mFd, descriptorID);
LOGD("close(fd = %d)", descriptor);
close(descriptor);
}
CmakeLists.txt 与 SerialPort.c 在同一目录下。
cmake_minimum_required(VERSION 3.4.1)
add_library(
serial_port
SHARED
SerialPort.c
)
find_library( # Sets the name of the path variable.
log-lib
# Specifies the name of the NDK library that
# you want CMake to locate.
log )
target_link_libraries(
serial_port
${log-lib}
)
在 android {} 中添加:
// 支持ndk,加载cmake文件
externalNativeBuild {
cmake {
path file('src/main/cpp/CMakeLists.txt')
}
}
SerialPort.java 的包名需与 SerialPort.c 中声明的一致。
package com.test.serialtool;
import android.util.Log;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileDescriptor;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
/**
* 该类的包名需与生成so时设置的包名相同
*/
public class SerialPort {
static {
System.loadLibrary("serial_port");
}
public native void close();
public native FileDescriptor open(String var1, int var2, int var3);
private File mDevice = null;
private int mBaudrate;
private FileDescriptor mFd = null;
private boolean isConnected = false;
private FileInputStream mFileInputStream = null;
private FileOutputStream mFileOutputStream = null;
public FileInputStream getInputStream() {
return this.mFileInputStream;
}
public FileOutputStream getOutputStream() {
return this.mFileOutputStream;
}
public SerialPort(File device, int baudrate) throws SecurityException, IOException {
if (device == null) {
Log.e("SerialPort", "device not null");
throw new IOException();
} else {
if (!device.canRead() || !device.canWrite()) {
try {
Process su = Runtime.getRuntime().exec("/system/bin/su");
String cmd = "chmod 666 " + device.getAbsolutePath() + "n" + "exitn";
su.getOutputStream().write(cmd.getBytes());
if (su.waitFor() != 0 || !device.canRead() || !device.canWrite()) {
throw new SecurityException();
}
this.mDevice = device;
this.mBaudrate = baudrate;
} catch (Exception var5) {
var5.printStackTrace();
throw new SecurityException();
}
}
}
}
public boolean openPort(int flags) throws IOException {
if (this.isConnected) {
return this.isConnected;
} else if (this.mDevice != null) {
this.mFd = this.open(this.mDevice.getAbsolutePath(), this.mBaudrate, flags);
if (this.mFd == null) {
Log.e("SerialPort", "native open returns null");
throw new IOException();
} else {
this.isConnected = true;
this.mFileInputStream = new FileInputStream(this.mFd);
this.mFileOutputStream = new FileOutputStream(this.mFd);
return true;
}
} else {
return false;
}
}
public SerialPort(File device, int baudrate, int flags) throws SecurityException, IOException {
if (device == null) {
Log.e("SerialPort", "device not null");
throw new IOException();
} else {
this.mDevice = device;
this.mBaudrate = baudrate;
if (!device.canRead() || !device.canWrite()) {
try {
Process su = Runtime.getRuntime().exec("/system/bin/su");
String cmd = "chmod 666 " + device.getAbsolutePath() + "n" + "exitn";
su.getOutputStream().write(cmd.getBytes());
if (su.waitFor() != 0 || !device.canRead() || !device.canWrite()) {
throw new SecurityException();
}
} catch (Exception var6) {
var6.printStackTrace();
throw new SecurityException();
}
}
this.mFd = this.open(device.getAbsolutePath(), baudrate, flags);
if (this.mFd == null) {
Log.e("SerialPort", "native open returns null");
throw new IOException();
} else {
this.isConnected = true;
this.mFileInputStream = new FileInputStream(this.mFd);
this.mFileOutputStream = new FileOutputStream(this.mFd);
}
}
}
public void write(byte[] buffer, int offset, int count) throws IOException {
if (this.isConnected && this.mFileOutputStream != null) {
this.mFileOutputStream.write(buffer, offset, count);
}
}
public boolean isConnected() {
return this.isConnected;
}
public int read(byte[] buffer, int offset, int count) throws IOException {
return this.isConnected && this.mFileInputStream != null ? this.mFileInputStream.read(buffer, offset, count) : 0;
}
public void writeLine(String text) throws IOException, IllegalAccessException {
this.write(text + "rn");
}
public void write(String text) throws IOException, IllegalAccessException {
if (this.isConnected && this.mFileOutputStream != null) {
this.mFileOutputStream.write(text.getBytes());
}
}
public int getAvailableByte() throws IOException {
return this.isConnected && this.mFileInputStream != null ? this.mFileInputStream.available() : 0;
}
public String readExisting() throws IOException, IllegalAccessException {
if (this.isConnected && this.mFileInputStream != null) {
int count = this.mFileInputStream.available();
char[] buffer = new char[count];
this.read((char[])buffer, 0, count);
return new String(buffer, 0, count);
} else {
return null;
}
}
public int read(char[] buffer, int offset, int count) throws IOException
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原文链接:https://blog.csdn.net/doris_d/article/details/109763641
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