Android 串口通讯-------android -serialport-api

最近一段时间公司接了个饮水机串口通信的项目，于是去百度、github查找一些资料

http://code.google.com/p/android-serialport-api/这是谷歌提供的demo，但无法运行，这就尴尬了

串口的操作无非就是几步：

1.打开串口（及配置串口）

2.读串口；

3.写串口；

4.关闭串口。

提到串口就不得不说JNI了,它使java可以直接调用C生成的库，为可在android中使用串口，通过配置生成一个c语言的动态链接库serial_port.so(自动命名成libserial_port.so），并把它放在了libs/aemeabi 里，其c源文件在JNI中，大家在下载了android-serialport-api的源代码后，将这两个文件夹copy到自己新建的工程中即可。生成.so文件请看JNI配置

相关代码

1，加载动态库.so文件

public class SerialPort {

private static final String TAG = "SerialPort";

/*
* Do not remove or rename the field mFd: it is used by native method close();
*/
private FileDescriptor mFd;
private FileInputStream mFileInputStream;
private FileOutputStream mFileOutputStream;

public SerialPort(File device, int baudrate, int flags) throws SecurityException, IOException {

/* Check access permission */
if (!device.canRead() || !device.canWrite()) {
try {
/* Missing read/write permission, trying to chmod the file */
Process su;
su = Runtime.getRuntime().exec("/system/bin/su");
String cmd = "chmod 666 " + device.getAbsolutePath() + "\n"
+ "exit\n";
su.getOutputStream().write(cmd.getBytes());
if ((su.waitFor() != 0) || !device.canRead()
|| !device.canWrite()) {
throw new SecurityException();
}
} catch (Exception e) {
e.printStackTrace();
throw new SecurityException();
}
}

mFd = open(device.getAbsolutePath(), baudrate, flags);
if (mFd == null) {
Log.e(TAG, "native open returns null");
throw new IOException();
}
mFileInputStream = new FileInputStream(mFd);
mFileOutputStream = new FileOutputStream(mFd);
}

// Getters and setters
public InputStream getInputStream() {
return mFileInputStream;
}

public OutputStream getOutputStream() {
return mFileOutputStream;
}

// JNI
private native static FileDescriptor open(String path, int baudrate, int flags);
public native void close();
static {
System.loadLibrary("serial_port");
}
}

2.C文件

JNI有一定了解的人就会知道，在写c语言链接库时候，函数的命名是和调用它的类所在的包名相关的，一旦包名与链接库中函数的命名不相符，就不能调用链接库的函数。这里可以打开jni中的.c文件

/*
* Copyright 2009-2011 Cedric Priscal
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0 *
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/

#include <termios.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <string.h>
#include <jni.h>
#include "com_cosin_serialport_SerialPort.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)

static speed_t getBaudrate(jint
4000
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_cosin_serialport_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 */

return NULL;
}
}

/* Opening device */
{
jboolean iscopy;
const char *path_utf = (*env)->GetStringUTFChars(env, path, &iscopy);

fd = open(path_utf, O_RDWR | flags);

(*env)->ReleaseStringUTFChars(env, path, path_utf);
if (fd == -1)
{
/* Throw an exception */
/* TODO: throw an exception */
return NULL;
}
}

/* Configure device */
{
struct termios cfg;
if (tcgetattr(fd, &cfg))
{
close(fd);
/* TODO: throw an exception */
return NULL;
}

cfmakeraw(&cfg);
cfsetispeed(&cfg, speed);
cfsetospeed(&cfg, speed);

if (tcsetattr(fd, TCSANOW, &cfg))
{

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_cosin_serialport_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);

close(descriptor);
}

3.操作串口

/**
* 进行串口通讯
*/
public class SerialPortData {
private long nowTimes;
public DeviceCodeCallBack mDeviceCodeCallBack = null;
public CmdCallBack mCmdCallBack = null;
public Timer mTimer = null;
private static SerialPortData mSerial = null;
private FileOutputStream fileOutputStream;
private FileInputStream fileInputStream;
private SerialPort serialPort;
private int size;
private SerialPortFinder finder;
private byte[] buffer;
private ReadThread readThread;
private int i = 1;
private Context Cotext;

public static SerialPortData getIntence() {
if (mSerial == null) {
mSerial = new SerialPortData();
}
return mSerial;
}

/**
* 打开串口
*/
public void openSerialPort(Context mCotext) {

Cotext = mCotext;
try {
serialPort = new SerialPort(new File("/dev/ttyS1"), Constant.BAUD_RATE, 0);
fileOutputStream = (FileOutputStream) serialPort.getOutputStream();
fileInputStream = (FileInputStream) serialPort.getInputStream();

Toast.makeText(mCotext, "打开成功", Toast.LENGTH_SHORT).show();
} catch (IOException e) {
e.printStackTrace();
}
}

private InputStreamReader inputStream;

/**
* 启动线程接收数据
*/
public void readReceivedData() {
Log.i("zy", "线程进行中" + fileInputStream.toString());
if (fileInputStream == null) {
return;
}
if (readThread == null) {
readThread = new ReadThread();
readThread.start();
}
}

/**
* 把获取到的数据转成十六进制后设置到TextView显示
*
* @param buffer
* @param size
*/
private void onDataReceived(final byte[] buffer, final int size) {

byteArrayToHex(buffer, size).toUpperCase();
}

/**
* byte数组转成十六进制
*
* @param buffer
* @param size
* @return
*/
public String byteArrayToHex(byte[] buffer, int size) {
StringBuilder strBuilder = new StringBuilder();
if (fileInputStream != null) {

inputStream = new InputStreamReader(fileInputStream);
BufferedReader bufferedReader = new BufferedReader(inputStream);
try {
String buff = bufferedReader.readLine();
if (buff.contains("+")) {
/**
* 截取+后面的数据
*/
String indexString = buff.substring(buff.indexOf("+") + 1);
Log.i("zy", "截取数据-----" + indexString);
isData(indexString);
}

} catch (IOException e) {
e.printStackTrace();
}
}
return strBuilder.toString();
}

/**
* 获取所有的串口设备
*/
public void getAllSerialPortDevices() {
finder = new SerialPortFinder();
String[] devices = finder.getAllDevices();
String[] paths = finder.getAllDevicesPath();
}

/**
* 接收串口数据的线程；因为串口设备每秒发一次数据，这里一直接收。
*/
class ReadThread extends Thread {
@Override
public void run() {
while (true) {
try {
buffer = new byte[512];
size = fileInputStream.read(buffer);
if (size > 0) {
onDataReceived(buffer, size);
}

Thread.sleep(1000);
} catch (IOException e) {
e.printStackTrace();
} catch (InterruptedException e) {
e.printStackTrace();
}

}
}
}

/**
* 输出字符串转字节
*/

public void OutStreamDevices(final String sendOrder) {

try {
if (fileOutputStream == null) {
return;
}
byte[] text = (sendOrder).getBytes();
fileOutputStream.write(text);
fileOutputStream.flush();
} catch (Exception e) {
e.printStackTrace();
}
}

以上就是我所有的操作。如果有问题，请联系本人，因没有直接在项目中实现，无法上传Demo,请见谅